Hi- It's my first post, and this is my 4th or 5th build. I've purchased a few boards from AION and love the product. Just wish I could get them to work!
I put together an Aion Refractor. The mods I made (based on what I had were-
-I initially socketed the diodes, but thought they were faulty so I soldered them in
-I believe I changed C14 to a 6n8
https://aionelectronics.com/project/refractor-centaur-overdrive/ (https://aionelectronics.com/project/refractor-centaur-overdrive/)
IC1 (LF353P)
1- 6.73
2- 6.73
3- 5.79
4- 0
5- 6.7
6- 6.69
7- 5.94
8- 9.36
IC2 (LF353P)
1- 8.24
2- 6.88
3- 6.73
4- 7.27
5- 6.74
6- 6.98
7- 8.25
8- 8.86
IC3- TC1044SPCA
1- 9.36
2- 9.36
3- 8.4 (fluxuates 8.4-8.1 up and down)
4- 7.28
5- 7.28
6- 7.93
7- 7.93
8- 9.36
I tried measuring D1, D2, D3 and D4, but not sure if I'm testing correctly. Sometimes they read 0 and other times they read -3 or -2.93
Regarding the sound- when the pedal is not turned on, there is clear working signal. When the pedal is engaged, the light turns on and there is clear guitar sound, but its noticeably quieter than the bypassed volume and there is no gain whatsoever. The volume pot works as it should but neither the tone nor dual gain pots work at all.
(https://s9.postimg.org/5m0ylc8ez/IMG_6131.jpg) (https://postimg.org/image/5m0ylc8ez/)
Did you insulate the bottom of that dual pot?
I haven't built the Refractor, but I've built the Nimbus which also uses a dual pot, and it sits right on the circuit board.
If I didn't isolate it with two layers of electrical tape, it certainly would have shorted out the board.
Not an expert by any means, but it looks to me as if the place to look first is around IC3. That and the surrounding circuitry should be generating all your power supply voltages. Those voltages don't look right, and the power supply pins to your op amps do not measure what the schematic says they should. IC1 power pins look about the same as the schematic, but IC2 should have -9V on pin 4 and +18V on pin 8. That -9V looks like it should be coming from IC3 pin 5, and the +18V comes from D4 and the circuitry around pins 1, 2 and 4 of IC3, so I would be looking for problems around there. Maybe shorted solder connections or similar.
Thanks for the replies- Here's the update. I actually removed the dual gain pot thinking it might be part of the problem. I replaced with two 250KB pots. Same problem- volume works, gain and tone do not.
I also took a look around IC3 as DIY Bass suggested and didn't see any solder issues, but maybe I'll try with a better magnifying glass.
I just looked back at the schematic. If I used a 500K pot instead of the 100k pot suggested, could that be the issue??
No.
If you have a voltage on pin 3 of the TC1044, you do not have a good ground. Pin 3 should be going directly to ground.
Make sure your IC socket for IC3 has good solder connections and that the IC is seated in the socket firmly.
Thanks Aph. I checked IC3 and it seems to be seated correctly. I'll remove the socket later and maybe try a different socket and IC.
I tried a different socket, seated it well, and a new IC and checked for solder bridges. As stated above, I assume there's a grounding issue somewhere. Would an audio probe be the next step? I'm pretty new to this and not sure how to continue. Thanks!
If you are decent at reading schematics, you could make continuity checks between the chassis and the ground points on the PCB (with power not connected). It looks like you have all the grounds going to the ground lug of your input jack, so connect one lead (with an alligator clip) to the stomp chassis and use the other lead to touch the ground points on the PCB, which can be done from the top. The first thing I'd do is touch the actual pin 3 of IC3. If you don't get zero ohms, there is a break somewhere. You could then try soldering an insulated thin wire under the PCB from pin 3 to a known good ground.
Yep, you aren't up to an audio probe yet. Get the power supply voltages correct first. A lot of what is currently wrong will then come good.
Ok- All that should go to ground goes to ground according to the continuity test. I had to run a wire from IC3 pin3 to ground as APH suggested and got the following numbers so far. I think it's an improvement.
IC1
1-1.4
2-1.4
3-1.38
4 -1.8
5 -5
6 -.47
7 8.73
8 9.36
IC2
1 16.03
2 -5
3 1.37
4 -8.7
5 1.37
6 .62
7 16.04
8 16.72
IC3
1 9.36
2 4.82
3 .3
4 -4.25
5 -8.68
6 4.3
7 5.8
8 9.35
Still no gain, but one of the two gain pots at least adjusts sound now. Nothing on tone pot. Volume pot still works
VB (pins 3 and 5 of IC2) should be half of the +9V value, which comes from pin 8 of IC3. So you are looking for about 4.6V on those pins, not 1.3 as you have now. Check R29 and R30 and make sure they are the correct values and that there are no solder problems around them. If they are both the same and soldered correctly you should be getting 4.5 to 4.6 V for VB easily.
Yeah, like DIY says ^^^.
You may also have other grounding problems. Go back to the schematic and check all the ground points on the PCB.
Ok- as mentioned, I substituted the dual gain pot for two single 250k pots. When the "top row" pot is at the halfway point and the "bottom row" pot is fully turned the voltages are at the following points.
iC 1
1 3.27
2 3.27
3 2.47
4 0
5 -.53
6 -.48
7 8.72
8 9.36
IC2
1 16
2 -5.5
3 3.27
4 -8.78
5 3.27
6 2.36
7 16
8 16.72
IC3
1 9.36
2 4.82
3 0
4 -4.25
5 -8.72
6 4.32
7 5.8
8 9.36
The gain significantly affect the voltages- I can adjust IC2 pin 3 from 3 volts to .8v by turning the bottom gain pot.
Am I getting closer?
If you look at the schematic, IC2 pin 3 is supposed to be a fixed voltage. It should not adjust. I would be looking for a solder bridge somewhere. Sounds as if that gain pot may be connected somewhere it shouldn't. Also - recheck the network around R29 and R30 and all the points where that network is connected to the circuit. You need a steady 4.5-ish volts on that pin.
I took all of the suggestions above into account- checking for solder bridges and rechecking to ensure proper grounding. The puzzler to me is that the gain pots affect IC2 pin 3, but the gain pot also affects IC1 pins 1,2. &3. I know that pin 3 of IC2 should have fixed voltage, but I'm at a loss as to what to do next. I checked the R29 area and actually replaced the resistors just in case.
Maybe post some photos of the top and bottom of your board and see if somebody else can spot any issues?
Here are some pics. I tried to scrape between the solder joints to ensure no bridges. I'm not sure how to test for solder bridges other than visually. Would a multimeter help with that?
The only addition is a black wire that runs from IC3 pin 3 to ground (connected to ground lug of the output jack)
(https://s9.postimg.org/reviapjij/IMG_0720.jpg) (https://postimg.org/image/reviapjij/)
(https://s9.postimg.org/enhc484ln/IMG_0721.jpg) (https://postimg.org/image/enhc484ln/)
(https://s9.postimg.org/h4t3bh92j/IMG_0722.jpg) (https://postimg.org/image/h4t3bh92j/)
(https://s9.postimg.org/a1l7vvbcr/IMG_0723.jpg) (https://postimg.org/image/a1l7vvbcr/)
(https://s9.postimg.org/jm4uirvjv/IMG_0724.jpg) (https://postimg.org/image/jm4uirvjv/)
(https://s9.postimg.org/pab59nkgr/IMG_0725.jpg) (https://postimg.org/image/pab59nkgr/)
(https://s9.postimg.org/3nw4smtm3/IMG_0726.jpg) (https://postimg.org/image/3nw4smtm3/)
Thanks for pix, mike... but unfortunately, it's really hard to see anything clearly. For me, I'd need much higher resolution pix.
I have to ask just because I'm curious and I have noted that other builders have had this problem with this exact unit.
Is C16 (1uF Tantalum) installed with the correct polarity?
I'll take better pix with a scanner tomorrow Aph. Hopefully that will help. And I'll also check the polarity of C16, Slowpoke. Appreciate the assistance!
Hey Slowpoke- I think you're onto something here! I do believe that C16 is reversed! That could be part (or all of the issue) I'll try to reverse or find another if I can't get it out cleanly.
(https://s9.postimg.org/vij5h5pmj/IMG_6152.png) (https://postimg.org/image/vij5h5pmj/)
(https://s9.postimg.org/iedl4m2rf/centaur_pcb.jpg) (https://postimg.org/image/iedl4m2rf/)
Yes, it is reversed. It probably isn't the primary cause of your troubles but everything helps.
It is not recommended to re-use a reversed capacitor. If you have a new one, use it and throw the old one out.
I wasn't able to take good pics of the board with a scanner but will try later with a better camera. In the meantime, it's possible that the PCB might have either residue or scratch marks that could be bridging. Is there a way to remove the "in-between" stuff as that might also cause the problems? Alcohol? etc?
Alcohol will remove flux but not solder. You would have to reheat the solder to remove. Flux usually does not cause a problem in audio frequency devices.
Thanks APH- It's possible that when I scraped the PCB that I exposed a bit of the copper underneath. Maybe that could be one of the bridges? Can I use something (like a Sharpie concept or something non conductive) to cover up the copper, thereby eliminating the possible bridge?
That's highly unlikely. If you scraped hard, you may have produced a sliver of copper that's touching something, but once again, pretty unlikely. Use a stiff toothbrush and brush the bottom of the board. Take a magnifying glass and inspect every connection on the bottom. If something is shorting, it's almost always a solder bridge. Having bare copper exposed on a PCB is not a problem. Years ago, a lot of PCB's were not coated at all.
The fact that you had to run a wire from pin 3 of IC3 to ground means that either that solder connection was bad or a copper trace to that pin broke on the board (kind of hard to do)... Perhaps other connections are bad or other traces have lifted off.
Is there an easier way of desoldering the small bypass board on the 3pdt switch? I think there might be a solder bridge issue as there don't seem to be any on the main PCs board. And using the continuity meter, a few of the lugs test as if they are grounded.
Although it doesn't directly show it on the bypass PCB documentation, it looks as if it could be reasonable to see three of the switch lugs connected to ground. If you look, the three lugs that don't show any connection to anything else on the PCB I think could all be safely connected to ground (and I think at least one of them needs to be in order for the LED to function). One thing to check is to make sure that the switch is rotated the correct way. I have a vague memory that somewhere you said that the LED was working correctly though. It wouldn't if the switch was the wrong way around.
I think that DIY Bass is correct regarding the bypass switch. Ground should be found on some of the switch lugs.
I do not recommend attempting to de-solder the 3PDT switch. You would most likely destroy the switch and the board. Without professional tools you are limited to using de-solder braid or a solder sucker (both are good tools to have anyway). The amount of heat that would be applied and the length of time involved would almost certainly damage the switch and the board.
On to a different problem, I've been looking at the latest voltages that you posted. The one that stands out the most is IC2 pin 7. You may have a short between pin 7 and 8. With no power applied do a continuity test between those pins. If you have a short try to resolder and test again. If it still shows a short remove IC2 and test those pins again. If the short has disappeared IC2 is most likely toast and needs replacement.
If there was a short or IC2 was faulty re-measure the voltages and post them here. You will get the problems sorted out, it will just take time and effort.
Quote from: Big mike 1100 on February 02, 2018, 12:40:25 AM
Is there an easier way of desoldering the small bypass board on the 3pdt switch?
If I recall correctly, Paul (PRR) has suggested a brief kiss from a blow-torch and a sharp tap on your bench-top. But that came with a pile of caveats and warnings involving fire and death and other non-optimum results... ::) TBH, I'd sling it out and wire a new switch yourself without the mini-board.
So I swapped IC chips 1 and 2 for TL072s and replaced the gain and tone pots in addition to touching up the solder joints. I think the voltages are more in line, yes?
IC1
1 4.69
2 4.69
3 3.55
4 0
5 4.7
6 4.7
7 4.7
8 9.36
IC2
1 4.81
2 4.7
3 4.6
4 -6.9
5 4.7
6 4.6
7 4.6
8 14.85 (seems a little low??)
IC3
1 9.36
2 4.8
3 0
4 -3.35
5 -6.84
6 4.3
7 5.8
8 9.35
Still no gain or tone control
If the voltages are right would an audio probe be the next step?
The voltages are fairly close. I would recommend taking out IC2 and then seeing if the +18V and -9V lines get closer to those actual voltages. If they do come up to those voltages, try a different chip for IC2.
An audio probe is the next step to try.
But before that have another look at C16. Usually a tantalum capacitor will have its positive leg marked on the capacitor's label area. Also the positive leg is longer than the negative (this is only valid when the capacitor is new and hasn't been installed and trimmed). On the Aion board the polarised capacitor positions have a square solder pad which identifies with the positive leg of the polarised capacitor. So with C16 its positive leg will be positioned next to R17 and its negative leg will be next to R6.
I believe C16 is correct- negative leg is closer to R6 and IC1. The writing was on one side of the cap, so the picture/PCB is orientated so it can be read. If I'm incorrect, please tell me.
Also, you are correct, Slowpoke. When I remove the TC072 from IC2, the pins read -9 and -18v. I tried 3 other TC072s, but all had lower readings. Are there a few "hotter" IC chips that I should try?
***
Edit- i tried JRC4558,LF353,NE5532,RC4558- all with same or worse results- nothing hit 18v. Would also swapping IC1 to make some other combination possibly increase the volts?
(https://s9.postimg.org/w3xlno8vv/626015_FB-_A087-4698-_A748-1723_EE1_E83_DF.jpg) (https://postimg.org/image/w3xlno8vv/)
(https://s9.postimg.org/x67s67c9n/D7203_E1_B-_C6_C4-48_DA-_A881-_A312_CFA4406_D.jpg) (https://postimg.org/image/x67s67c9n/)
As shown in your pictures C16 is installed correctly. Sorry to be so annoying about it but incorrect installation is a very common error with this particular effect.
It is interesting that the other chips that you have tried have similar to worse results with the +18V and -9V rails. I don't see these chips being able to pull enough current to pull those rails down unless they are faulty - which is not likely. IC3 may be a low spec' chip - works but isn't working well. If you have another one try it and see. I have had problems before with these chips working but falling over when slightly loaded or just plain failing. But your voltages should be high enough to see if the effect will work.
An audio probe is next. Start off IC1 pin 3 and then pin 1. If there is audio there move on to pin 5 and then 7. Then IC2 pin2 and then pin 1. Next is pin 6 then 7. Audio should be present at all stages. Remember that the gain and tone controls will have some effect on the levels and tone. Where the audio stops go over that area carefully and the one before it.
The board connection SW2-1, make sure that it is not permanently grounded by the footswitch. It should be grounded only in bypass mode. If you do have audio passing in bypass mode IC1a (pins1, 2 & 3) is fine.
I'll try testing the pedal tomorrow, but swapping out IC3 for another chip definitely helped.
I now have a JRD558 in IC1 and a TC072 in IC2
The new IC3 readings
1 9.36
2 4.82
3 0
4 -4.36
5 -9
6 4.3
7 5.8
8 9.36
New IC 2
All 4.7s except Pin 4= -9 and Pin 8= 17v
Thanks, Slowpoke. Really appreciate your help. Here are the results so far.
IC1-
Pins 1&3 are fine
Pins 5 and 7 are quieter than 1&3 but clear
IC2
Pin 1 is fine
Pin 2 - NO sound
Pin 6 NO sound
Pin 7- good sound and good volume
I tested SW 2-1 and it's only grounded in bypass mode. You also wrote "If you do have audio passing in bypass mode IC1a (pins1, 2 & 3) is fine." Was I supposed to do something with that?
My comment regarding passing audio in bypass mode was referring to IC1a. If audio does pass then that section of the circuit should be OK. But from your tests it is OK anyway.
I would expect IC1 pin 7 to have a very high volume level on it. Check your gain pot and make sure that it is working. Double check all components around IC1b and IC2a. I do have a question regarding C8 (390pF) and C13 (820pF), are you sure that they are the correct values? They seem to be overly large for those small values.
Any progress on a better camera? Clearer pictures would really help.
Are these better pics? I might have made them too big. The markings on the caps for C8 and C13 are 821J 100v and 391J 100v. I thought they were right, but am not 100% certain as other builds seem to use the smaller ceramic caps
(https://s9.postimg.org/vefqdxo6j/320_D20_B4-_B198-4_AF7-82_EF-59962_DF26_A71.jpg) (https://postimg.org/image/vefqdxo6j/)
(https://s9.postimg.org/7ngcvsdor/91_D95300-_D7_A3-4_AF4-99_E5-_FD376_A08371_D.jpg) (https://postimg.org/image/7ngcvsdor/)
(https://s9.postimg.org/43uf5zqej/C8_F55_E3_E-76_CE-4_AC2-_B089-7_DE1_D66_A0432.jpg) (https://postimg.org/image/43uf5zqej/)
Nope, those ones are correct. A lot of people just use MLCC ceramics because it's harder to find those odd values in film caps. But the original Centaur used films like you're using.
Thanks Aion! Appreciate the reply.
I'll check the other components. What's the best procedure to check the gain and tone pots to make sure they are working? Is it an ohm test or more of a continuity test?
So I did some testing. Not sure what this means, but here are some outcomes:
Each lug of the Tone Pot is much louder than the lugs of the two gain pots (all lugs have audio)
Several components only have sound on one of the legs- Tracing the path via the schematic:
IC2a pin 2 no sound
R22 Right leg has tone, not left (Per PCB board orientation, not schematic)
R20- Bottom leg has tone, not top
C 13 Bottom leg has tone not top
R21 both legs have tone
IC2B pin 6 no sound
C14 Top leg has tone, not bottom
R24 Top leg has tone, not bottom
R23 both legs have tone
IC2 pin 7- good tone
Does this tell us anything?
So I tested the board tonight with an audio probe-
It appears that per the schematic, there is no audio coming from everything that stems from IC3, namely:
D3
D4
LEDR
Z1
R29
R30
C17
C20
C21
C22
C19
C18
There is also no audio from the path starting with C16. Namely:
C16
R19
R16
C12
R15
R17
R18
And IC2 has no audio from pin 2 or 6, but it's loud and clear in pin7
And what should I be hearing from IC3? I ask because I'm hearing nothing on any pin, except a high pitch squeal on one of the pins (Just forgot which one).
Could it just be another bad TC1044 IC in IC3 that's working but not working well enough, and maybe a bad C16? There were several resistors that had audio, but were noticeably quieter than the others
The only noise that you would get from IC3 is a high pitched squeal. It is a DC/DC converter using charge pumps to generate the +18V and -9V rails. However you are getting audio in places that is a bit odd and no audio where it should be expected.
Does your audio probe have a capacitor in series with the probe?
It does have a capacitor- a .1uf I believe. I set it up like as recommended like this video.
https://youtu.be/jWvIfDSxbIk
I was going to just start at C16 and either replace parts and test as I go or examine each more carefully. Is there a better plan?
Where is the audio that shouldn't be there and vice versa? I assumed that you should hear the audio at each point along the schematic.
A very quick way to set up an audio probe. Should work fine.
From your previous posts you are get a low level of audio on IC1 pin 5 and 7. It should be a far higher volume on pin 7. But your voltages are correct so your gain level must be somewhat low. Check all the components around IC1B and make certain that the gain pot does work as a pot. Test it with resistance test on your multimeter. I also note that you are using two separate pot for the gain...For your tests set both pots to mid-range and make sure that the connections are correct. Things get a bit funny when using two pots in place of a single dual pot - one of the pots has to be wired in reverse if you want to maintain the correct rotation control direction - eg, fully CW (clockwise) is maximum.
Have a look here; http://www.coda-effects.com/p/klon-centaur-circuit-analysis.html (http://www.coda-effects.com/p/klon-centaur-circuit-analysis.html) for a simple breakdown of the circuit's operation. It may help you to narrow in on the problem.
Thanks Slowpoke-that's a really helpful page- it looks like much of the problem could stem from the 100K gainB, as I can trace a line of bad components from that pot to all of the non-audible components:
R15-R17-R18-C12 and maybe R19 and C16, but I'm still learning how to read a schematic and the flow.
I'll start by disconnecting the two separate gain pots and putting the dual pot in place.
Am I correct that there should be no audio in all of the components coming off if IC3, at the bottom right part of the schematic?
Quote from: Big mike 1100 on February 07, 2018, 01:56:13 PM
Am I correct that there should be no audio in all of the components coming off if IC3, at the bottom right part of the schematic?
Correct, no audio on IC3 - its only function is to convert the 9V input voltage to +18V and -9V.
Well I replaced the two gain pots with the correct dual gain pot, mounted to the PCB board. I also replaced C16, just for good measure (mounted the correct way). I touched up the solder joints and looked for bridges. Same results.
I think at this point, I'll take a break from it and look at other projects, unless there is another suggestion to try.
Thanks!
I can't see any way that you could have audio on pin 7 IC2 without audio on Pin 2 and 6 of IC2. I thhink that there must be a short somewhere there to earlier in the circuit. What you want to do is follow through the circuit from one end to the other and see where the signal disappears. Try these points first and let us know what you find. You can do this.
IC1 pin 3
IC1 pin 1
IC1 pin 5
We know it doesn't get to IC 2 pin 2, so I would check somewhere around R13 and R16 as well and just what audio you have there.
The IC2 pin7 audio (which is LOUD and Clearer than other parts of the board) confuses me as well. I'll give it a shot and report back.
It looks like there is more than one path in the circuit based on the link that Slowpoke provided me a few posts back- A bypass path and clean path and maybe two gain paths. I'll try them all again.
Question 1-when I probe the path, there are some components that have audio on one leg but not the other- like R8 and R9, whose legs seem to go to VB. Is this normal or are those components suspect? There are others with that issue as well. Are they even part of the audio path or their leg is just in the way??
Question2- could it still be a bad IC3 at this point, or one of the other ICs for that matter?
Thanks for the advice!
I haven't found anywhere the actual track layout for the board, so not much help here, but I would be suspicious of a short from the track connected to pin 7 IC2 to somewhere earlier in the signal chain. I would be looking at anywhere you have 2 pads close together that should not actually be touching according to the schematic, and measure them with a multimeter to see whether there is any connection that shouldn't be there.
I do recommend that you try to clean the solder flux away on the solder side of the board. Methylated spirits, denatured alcohol or similar products can usually clear flux. An old toothbrush is very useful.
A picture that you posted a while ago showing the solder side of the board is of fairly low resolution and is a bit hard to see things. Additional magnification just makes the image worse but it has shown a few areas to check. In the following picture I have outlined the areas that may require attention. Some joints do not appear to be fully soldered or there is excess solder that may cause a short - IC1 pins 5 to 7 may have a problem.
(https://s13.postimg.org/jo7visx3n/Aion_Refr_Solder1.jpg) (https://postimg.org/image/jo7visx3n/)
See what you find.
Now, Vb is the 4.5V reference rail. It should not have any audio on it. So if a leg of a component is connected to Vb that leg will not have audio on it but the component's other leg may have audio on it (depending on where in the circuit it connects to).
IC3 is generating the correct voltages (from your measurements), so it is working and not to be worried about.
A high level of audio on pin 7 of IC2 is odd considering there is no audio on pin 6. I can't explain that yet but make sure that pins 5 and 6 of IC2 are not shorted together.
Thanks for the additional help! I'll purchase some denatured alcohol and have at it tonight, in addition to your and DIY Bass's other suggestions.
IC2 is a pair of inverting stages. It's perfectly normal not to have audio at either input of an inverting stage... in fact, if there *were* signal there, it *would* be a problem.
The opamp's job is to drive the feedback such that both inputs have the same voltage... in the case of an inverting stage, the non-inverting input is held to a constant DC voltage, and the feedback connects to the inverting input.
Looking at the schematic there should be audio on pins 2, 1, 6 and 7 of that IC. If there is not then there is definitely a problem of the "It's busted and I can't hear anything at the output at all" kind.
Thanks again for all of the help. I took all of the suggestions and here are the results.
I cleaned the board with Methylated spirits and here are the new pics of the back of the board. The Yellow circles represent the pins/joints that are testing positive for continuity. Not sure if they should or not.
****Edit*** I uploaded one picture with colored markings that show which pins are connected to each other by matching colored circles- The pics below all have separate circles- Just thought of it as soon as I hit "post" sorry.*****
Regarding what DIY Bass said- I traced IC1 Pins 3-1-5 and While Pin 3 and 5 showed normal clear volume, Pin 5's volume was clearly quieter and more trebly. He also mentioned testing R13 which had the same quieter, trebly sound as pin 5 of IC1.
Regarding R16- the pin on the right (facing the front of the PCB) had the same quiet/trebly sound, but the left pin had no audio.
Slowpoke said "A high level of audio on pin 7 of IC2 is odd considering there is no audio on pin 6. I can't explain that yet but make sure that pins 5 and 6 of IC2 are not shorted together." I checked and they are not, but the pics with the yellow circles show which pins test positive for continuity.
I'm not sure if I should be testing anything additional based on the last comments from DIY Bass and Highwater. I haven't desoldered anything at this stage, as I've touched the joints up several times and don't want to create the possibility of additional bridges unless you guys say so.
(https://s18.postimg.org/rqpz5yi2t/IMG_6223_1.jpg) (https://postimg.org/image/rqpz5yi2t/)
(https://s18.postimg.org/5di8j2wjp/IMG_6223.jpg) (https://postimg.org/image/5di8j2wjp/)
(https://s18.postimg.org/xdmc35pnp/IMG_6212.jpg) (https://postimg.org/image/xdmc35pnp/)
(https://s18.postimg.org/lbqy900zp/IMG_6213.jpg) (https://postimg.org/image/lbqy900zp/)
(https://s18.postimg.org/6fsf1exat/IMG_6214.jpg) (https://postimg.org/image/6fsf1exat/)
(https://s18.postimg.org/j76l7yhdh/IMG_6218.jpg) (https://postimg.org/image/j76l7yhdh/)
(https://s18.postimg.org/75b7dsd9x/IMG_6220.jpg) (https://postimg.org/image/75b7dsd9x/)
(https://s18.postimg.org/7i2ljz39h/IMG_6221.png) (https://postimg.org/image/7i2ljz39h/)
(https://s18.postimg.org/ovcvysvzp/IMG_6230.jpg) (https://postimg.org/image/ovcvysvzp/)
Once again, kind of fuzzy and hard to really see... but on your first photo, just below the two yellow circles, it looks like a possible solder bridge. Looking at the top of the board, this would be a short between R13 and C3 (I think).
And another possible bridge about three pads to the left of the left yellow circle...
Thanks APH- I resoldered and didn't see a bridge between either set, but there is continuity between the three joints marked in yellow in this pic. Is that normal?
(https://s18.postimg.org/58j2nbu3p/4_C327_D27-4026-4_E21-_BD90-7_DE230_D904_F9.jpg) (https://postimg.org/image/58j2nbu3p/)
Yes, that is normal for those points in this circuit. If you look at the circuit you will see that several other components also connect to those points; R5, C4 and C2. Pins 1 & 2 of IC1 & C3 make up those three points that you have tested as having continuity together.
If you now test the other leg of C3 you should find that R6, C5 & R7 are connected together. Refer to the circuit as you do this. If all those parts test as being connected, move on to the next test. If they appear to have a problem, double check your testing and if that is OK start to look for a broken track connecting these components. Repair the fault.
The next test is to go to the other leg of R6 and make sure that it is connected to C5, IC1 pin 5 and one terminal of the GAINA pot (this is shown on the circuit as 1). Repair any problems.
Now you should have gotten the hang of stepping through the circuit and seeing how the components are connected together so proceed to test the connections between the GAINA pot terminal 3 (test terminal 2 by seeing if there is continuity with one leg of R30 - the other leg of R30 connects to ground) and R10. Fix any problems found.
Continue test all the component connections around IC1B....I think that you will find your problem with this part of the circuit. The problem is that it has very little gain. See how you go.
Just remember that the circuit must not be powered when doing a resistance or continuity test.
Quote from: Big mike 1100 on February 11, 2018, 07:17:01 PM
Thanks APH- I resoldered and didn’t see a bridge between either set,
Yes, the picture you just posted shows no bridging now.
I"m doing a continuity test as suggested but I'm puzzled. Slowpoke, you mentioned connecting one terminal of the GainA pot to R30. I'm not following that on the schematic. I see where it connects to R10.
When I do the test, terminal 1 of the GAINA pot does, in fact, connect to both C5 and R6, but neither R30 nor R10 (which I thought was the logical connection based on the schematic- still learning to read them) show connectivity. I sense the issue is with or around the gain pot.
There's also no connectivity with GAINA terminal 2 and either leg of R30
Quote from: Big mike 1100 on February 11, 2018, 09:49:34 PM
I"m doing a continuity test as suggested but I'm puzzled. Slowpoke, you mentioned connecting one terminal of the GainA pot to R30. I'm not following that on the schematic. I see where it connects to R10.
When I do the test, terminal 1 of the GAINA pot does, in fact, connect to both C5 and R6, but neither R30 nor R10 (which I thought was the logical connection based on the schematic- still learning to read them) show connectivity. I sense the issue is with or around the gain pot.
There's also no connectivity with GAINA terminal 2 and either leg of R30
The points labeled VB on the schematic all connect together. Terminal 2 of the GAINA pot is the middle terminal (the wiper). If you look at all points labeled VB, you will see, that indeed, terminal 2 of GAINA is connected to R30. C18 may be messing up your reading (it shouldn't, but...). Make sure your power connector is completely unplugged and let the pedal sit for a bit while C18 completely discharges. If you still get an open circuit reading or high ohms reading, you have a problem.
Thanks Aph- neither of the pin 2s of the dual gain pot show connectivity to R30.
Also, Since it's a dual gain pot, there are 6 lugs. Facing the pcb, with the pot on the "solder side", the pins are marked like this, for my explanation:
6-5-4 (top pins of the dual gain)
3-2-1 (bottom pins of the gain pot)
Here's other info- when I rotate the gain pot to the left there's connectivity on pins 5&4 and also for 2&1 for both GainA and GainB. There is also, however, connnectivity between pin 6 and pin 1
When the pot is rotated to the right, there's connectivity between 6&5 and 3&2 for both gain pots and no cross connectivity like when the pot is rotated left. *actually- all 4pins (6,5,3&2 are all connected to each other when rotated right
(https://s18.postimg.org/h1q2j2flx/C8187786-_AFDD-46_B3-_BCC1-7_FAA5_E7_C27_D5.jpg) (https://postimg.org/image/h1q2j2flx/)
Things can get confusing at times.
I've put labels on the GAINA and GAINB pots to match up with your description.
(https://s13.postimg.org/wp2yukx37/Refract_SCH1.jpg) (https://postimg.org/image/wp2yukx37/)
If you look closely you will see that VB connects to terminals 2 and 6. So those two terminals are permanently connected together. You may wish to confirm this. From your description of the way the terminals connect when fully CW and fully CCW it would appear that the two pots are connected correctly. But may not be connected to VB.
(https://s13.postimg.org/6i1rydmgj/Refract_SCH2.jpg) (https://postimg.org/image/6i1rydmgj/)
You may want to see if any other circuit points marked VB do actually connect to R30.
****I'm reposting my original*****
This gets a bit confusing!!
In terms of connecting to VB and to each other-
R8-R9-R30 and IC2A pin3 all connect to each other but not the ones below
GainB- 3, GainA-2 and R2 connect to each other but not the ones above
OK, from your latest results I think that you may have PCB track damage with the GAINA, GAINB pot connections.
The following picture shows the VB connections in that area. Terminal 3 of GAINB is the common connection point. R2 probably connects to terminal 2 of GAINA. A connecting track is clearly visible between terminal 3 of GAINB and terminal 2 of GAINA.
(https://s13.postimg.org/5by8j1mub/Cent_PCB1.jpg) (https://postimg.org/image/5by8j1mub/)
Find the damage and repair it or simply connect the damaged tracks with jumper wires. You may have damaged the PCB when removing the gain pot earlier. The PCB is double sided and "Plated Through". The through plating is in every hole (usually) and connects the upper and lower pads for a hole together. It forms a tiny metal cylinder. This cylinder can be damaged or even completely removed when de-soldering. Needless to say that it would also be damaged/removed if you ran a drill through the hole.
Repairing tracks connected to the gain pots will not be easy as the pot itself is in the way.
Slowpoke, I just reposted my findings- sorry to be confusing, but I want to give the best info possible!
Now it's easier.
Check the tracks that connect to GAINB terminal 3 and GAINA terminal 2.
I think that GAINB terminal 3 is the common connecting point considering how close R8, R9 and R30 are to it.
R29 should also be connected here.
Run a short jumper wire from GAINB terminal 3 to the leg of R9 that is closest to GAINB terminal 3.
See if things get connected correctly.
Thanks Slowpoke! Just to confirm- these two points, right?
Close enough to create a deliberate solder bridge on the top of the board but probably not the best idea, right?
(https://s18.postimg.org/97pxgt43p/5_F21_F5_AE-_F562-4133-_AAF1-5_C307_F02_F19_E.jpg) (https://postimg.org/image/97pxgt43p/)
Make sure that particular leg of R9 does connect to R8 and R30. If it does then connect that leg to GAINB terminal 3 via a short length of wire or just bridge it with some solder to quickly see what happens. If VB connections are then restored, replace the bridge with wire for a more permanent solution.
Bridging the connection restored all of the VB connections, so they are all together, but there is still no effect when the pedal is on and the gain or tone pots are turned. Just the volume pot.
Any thought on next step?
Well at least that is one problem solved. There is probably some more damaged/broken tracks connecting to the gains pots' terminals. So you are now back to testing continuity of all the component connects associated with the gain pots and all the components connections around IC1B.
Tedious but still necessary to do. But first change IC1 to a TL072 (or similar) and see if there is any difference. Some voltage measurements would be a good idea too.
Will do. Thanks!
First puzzler- GainA lug3 does not have connectivity with R10, but does with R8. Is this normal?
Possibly a bit of confusion as to which pot is which.
(https://s13.postimg.org/bxk5aek2b/Refract_PCB2.jpg) (https://postimg.org/image/bxk5aek2b/)
R8 and R10 are next to lug 3 of GAINA but only R10 will connect to it. R8 should connect to lug 3 of GAINB.
Thanks Slowpoke-No confusion I don't think. For some reason GainA lug 3 ( the lower hole next to R8&R10) has connectivity with left leg of R8( green circles in pic))and does not connect to either leg of R10 (red circles in pic) hence the puzzle!
(https://s18.postimg.org/8jvbml0sl/99_BAFDB6-681_F-46_B8-87_E8-541_CAFFD7_ED8.jpg) (https://postimg.org/image/8jvbml0sl/)
This is confusing. Something appears to be wrong.
Could you determine which components are connected to each terminal of both pots please.
This will help to determine what is going on here.
Just a thought....
Set the gain pot(s) to mid-range (12 O' Clock) and do the same conductivity test. You may find that the funny connection has gone but R10 is still not connected to terminal 3 of GAINA. If that is the case, install a small link (as you did before with the other pot terminal and R9) between the end of R10 that is closest to terminal 3 of GAINA. Then make sure that the other leg of R10 connects to one leg of R11 and one leg of C7. If this is good proceed to test if terminal (lug) 1 of GAINB connects to R8. One leg of R8 goes to VB and therefore terminal 3 of GAINB. If it doesn't connect to R8 find out why and repair the problem.
Just in case you are wondering, R8 is connected in parallel with the resistance track (terminals 1 and 3) of GAINB.
*** Corrected a major error. I got R8 confused with R10. Oops....All fixed.
I'm working on it now- for some reason R8 is connected to both GainA lug3 and GainB lug 3.
I'll figure out the rest
I just updated my last message. Check it out.
With the pot at the midpoint the connection between R8 and gainA-3 disappears, but remains with gainB-3. That's what you mean in order to proceed, right? I want to make sure we're not saying different things referring to A vs B
For what it's worth, before I turned the pot to midpoint- R8, R9 and R30 were connected to both gainA lug3 and gainB lug3. When it's at midpoint, they're no longer connected to GainA-3 but still connected to GainB-3.
That all makes sense and appears correct..
Proceed with the other checks and then try the link to R10.
Let us know how you go.
Really appreciate your help! Ok- did everything you suggested and i think we got the results you/I were hoping for.
One leg of R8 is connected to R11 and C7
The other leg of R8 is connected to GainB 1&2 at midpoint&CCW and GainB 1,2&3 when fully CW,
The gain pot is making a slight ticking noise when a string is strummed but isn't doing anything in the way of Gain - same with the tone pot.
Make sense so far?
Always happy to help, these little puzzles can be fun. OK, let's see.
One leg of R8 is connected to R11 and C7
This should be one leg of R10 and not R8. ****** I made an error on an earlier post. I confused R10 with R8.
The other leg of R8 is connected to GainB 1&2 at midpoint&CCW and GainB 1,2&3 when fully CW,
Seems to be OK..
The gain pot is making a slight ticking noise when a string is strummed but isn't doing anything in the way of Gain - same with the tone pot.
Still have a problem, obviously.
Have you linked the R10 leg closest to GAINA terminal 3 to GAINA terminal 3 yet? **** See above comment regarding my confusion with R8 and R10. Connect the R10 (not R8) leg closest to GAINA terminal 3 to GAINA terminal 3.
**** Little errors like this don't help. Sorry.
No worries! I did everything that you mentioned to R8 and nothing to R10- Gain pot and all. Should all of that been to R10 and not R8? Can you repost, just so I'm clear? Thanks!!
Quote from: Slowpoke101 on February 12, 2018, 07:16:23 PM
Just a thought....
Set the gain pot(s) to mid-range (12 O' Clock) and do the same conductivity test. You may find that the funny connection has gone but R10 is still not connected to terminal 3 of GAINA. If that is the case, install a small link (as you did before with the other pot terminal and R9) between the end of R10 that is closest to terminal 3 of GAINA. Then make sure that the other leg of R10 connects to one leg of R11 and one leg of C7. If this is good proceed to test if terminal (lug) 1 of GAINB connects to R8. One leg of R8 goes to VB and therefore terminal 3 of GAINB. If it doesn't connect to R8 find out why and repair the problem.
Just in case you are wondering, R8 is connected in parallel with the resistance track (terminals 1 and 3) of GAINB.
I changed the above paragraph to now read correctly. I meant to say R10 and not R8.
I have triple checked it and it should be correct.
The sentence "Just in case you are wondering, R8 is connected in parallel with the resistance track (terminals 1 and 3) of GAINB." is correct but not to be worried about.
Thanks! Made the changes- still no gain or tone, but no ticking sound in the gain pot and I believe things are now linked to the gain pot correctly.
Progress...Every step gets us closer to getting the effect to work.
Make sure that R10 does now connect to GAINA terminal 3.
Next, check GAINA terminal 1 for continuity with IC1 pin 5, R6 and C5. Repair any problems.
Then check GAINB terminal 1 for continuity with R8 (just to make sure), R5, C4 and C6. Repair any problems.
Let us know how you go.
"Make sure that R10 does now connect to GAINA terminal 3." YES
"Next, check GAINA terminal 1 for continuity with IC1 pin 5, R6 and C5". YES
Then check GAINB terminal 1 for continuity with R8 (just to make sure), R5, C4 and C6." YES
Let us know how you go. All connected as they should be! Whew!
So far so good. It has been a bit of an ordeal to get to this point. Now what?
Apply a signal to the input and do some audio probing of IC1. Is there now audio on pin 5?
Is there any audio on pin 7. Does it change with varying the gain pot(s).
Some voltage readings on IC1 would be good.
Looks like the wife is asleep. In order to remain married, I'll start the audio probe tomorrow and post results. Thanks again for everything!
Quote from: Big mike 1100 on February 12, 2018, 10:35:54 PM
Looks like the wife is asleep. In order to remain married, I'll start the audio probe tomorrow and post results. Thanks again for everything!
I think that not waking the wife is a very good idea. We will just have to wait for your results tomorrow. Cheers.
Ok- did an audio probe!
IC1
Pin 1- clear tone- pots have no effect
Pin 2 same as pin 1
Pin 5 clear, but quieter tone when Gain is CW when Gain is CCW there's no audio
Pin 7 when fully CCW no audio, when slightly less than full CCW until about halfway- the volume/gain seems to increase until just short of full CW, then the audio gets choppy and breaks up.
Will get IC1 voltages shortly
IC1 voltages
1 4.67
2 4.67
3 3.5
4 0
5 4.6
6 4.6
7 4.7
8 9.18
Pin 3 seems a little low in voltage. May be worth chaging IC1 to see if the voltage gets a bit closer to 4.5V or so. Not really a problem at the moment.
The audio on pins 5 and 7 behave the way they should when the gain pot(s) are varied. So far so good. Now what happens to the audio signal after pin 7?
But first, confirm that C16 positive leg connects to R7 and R19 (continuity test) and that the negative lead of C16 connects to ground. Repair any problem if any found.
Next, audio probe time again. Make sure that the pedal is not is bypass mode and then follow the audio path (gain pot - midway).
Start at pin 7 then check for audio on both pins of C9, R13, C10 and R16. Check for audio on pin 2 of IC2. Also with the gain pot at the midway point check for audio on terminal 2 of GAINB pot.
See what you find and let us know.
I copied your post and added comments:
"But first, confirm that C16 positive leg connects to R7 and R19 (continuity test) and that the negative lead of C16 connects to ground." YES
"Next, audio probe time again. Make sure that the pedal is not is bypass mode and then follow the audio path (gain pot - midway". OK
"Start at pin 7 then check for audio on both pins of C9, R13, C10 and R16". —YES BUT ONLY ONE LEG ON R16- OTHERS HAVE AUDIO ON BOTH LEGS
"Check for audio on pin 2 of IC2." NO AUDIO- almost sounds like it's grounding.
"Also with the gain pot at the midway point check for audio on terminal 2 of GAINB pot." very, very low volume
Remove IC2 and see if the level of audio on pin 7 (the IC socket) comes up at all. If it does come up, try another IC for IC2. See what happens. If it doesn't come up in level remove IC2 again and measure the voltages on the socket - only pins 8, 5, 4 & 3 will have voltages on them. Pin 2 will also have a voltage on it which should be about 4.5V. Make sure that pins 2 and 3 are not shorted together.
Let us know what happens.
This is odd
I removed IC2- it took the sound away from the whole board
There is also voltage on all 8 socket pins not just the few mentioned
1 4.4
2 4.6
3 4.6
4 -9.17
5 4.6
6 4.4
7 4.4
8 17.6
Even when I put the IC chip back the audio is gone from the board-I don't have extra IC chips where I am, but have access tomorrow.
****crazier still is that now the only sound is Pin 7 of IC7 with the chip in- quiet trebly sound that gets affected by the gain and tone pot******
Scratch my last chaotic post- things have changed. I'll see what's going on and repost in a few.
Slowpoke- just to confirm, did you mean remove IC1 or IC2 to test pin7?
Idiot here forgot that there are resistors connecting some of the pins of IC2 together so that there exists a current path from the pin 2 connection. So the values that you are reading are OK. Notice that the voltages on pins 8 and 4 are now closer to +18V and -9V. IC2 may be unwell.
Remove power and whatever your are using for IC2. Check that there are no shorts between any of the pins on the socket. The only pins that should be shorted together are pins 3 and 5. If you find any other shorts make sure to repair them.
Now, no audio at all anywhere on the board with IC2 removed. And still no audio when IC2 is reinstalled. OK. That's different. Very odd. I will have to think about that. In the meantime check the connections between the components attached to IC2 pin 7. This will include the volume pot. Also is there any chance of uploading a photo of the board and its wiring to the stomp-switch, the input and output jacks?
Getting some spare ICs would be a great idea.
Here is a schematic that also shows the connections to the stomp-switch and the input / output jacks. It may help with following how the components are supposed to be connected.
(https://s13.postimg.org/vh815g7nn/klon-centaur-schematic.png) (https://postimg.org/image/vh815g7nn/)
I have been referring to IC2. Removing IC1 will stop all audio on the board.
So the audio came back on the board- no clue what happened. With IC2 out there is actually audio on pins 2,5&7 (socket only). With the IC in the socket there is no audio in 2 or 5 and very "good distorted" audio on pin 7
There are no shorts other than 3&5 together.
I actually bought the IC kit from small bear that has a bunch of spare ICs. Just don't have them with me. I'll be able to swap.
Any other steps before I can swap IC2?
****actually- I just swapped the IC1 chip with the IC2 chip- same results so it's prob not the chips.
The audio has come back? There may be an intermittent connection somewhere. As long as you have audio at the moment don't be too concerned yet.
Now, IC2 (yes, IC2). With IC2 removed I would expect audio on pin 2. Audio of a lower level may be heard on pins 1, 6 and 7. This audio would be passing through the components in the tone control circuit. The audio level at pin 7 would be far lower than what can be heard at pin 2. Remember that IC2 is not installed. You last posted that audio was found on pin 5...Was that a typo and you meant pin 6.
No shorts where they shouldn't be is good. Reinstall IC2.
You said that with IC2 (?) installed you have no audio on pin 2 but good distorted audio on pin 7. Does the audio on pin 7 vary with the gain pot and the tone pot?
Swapping IC1 and IC2 makes no difference. OK. The chips are most likely OK.
YES typo- Pin6- sorry!
"You said that with IC2 (?) installed you have no audio on pin 2 but good distorted audio on pin 7. Does the audio on pin 7 vary with the gain pot and the tone pot? "
YES- IC2 pin7 varies with the gain and tone pot.
So far so good. Audio probe time.
Starting at IC2 pin 7 check for audio then check for audio on both pins of C15 and R25 then terminal 3 of the volume pot. Repair any broken connections. If all good then set the volume pot to mid-range. Check for audio on terminal 2 and if present vary the volume and confirm that the level changes. If it does - good. If it doesn't the the volume pot may be faulty or you have a short to ground on terminal 2.
If all is good so far, see if audio is present on the board connection point SW1-3. If it is there follow the connecting wire to the stomp-switch board. Chase the audio there. Let us know what happens.
I followed it to SW1-3 and onto the stomp-switch at point SW1-3. So far so good!
Now you need to follow it through the stomp-switch and the PCB.
Find out why it is not connecting to the output jack.
the signal goes right to the output switch, but the gain and tone pots don't have any effect on the signal. Only the volume pot.
Could something in the switch have an effect on gain and tone and not just the signal controlled by the volume pot?
Or maybe put another way, IC2 pin 7 is loud and the volume pot has no effect on it, but the gain and tone pots do. Is there a way to see where the gain and tone pots fall off during the trace? The plain audio seems to make it through, but Gain/tone don't have any effect at the end of the signal.
Gain/Tone have no effect at SW1-3, but Volume does
on R25 Volume has no effect but tone and gain do. I guess volume is not in the path yet?
Would working backwards make sense somehow?
I think that there is something wrong with your stomp-switch and/or its PCB.
Disconnect SW1-3 at the stomp-switch PCB. Now audio probe that lead. You may find that the audio signal is varied by the gain/tone/volume pots. If you now probe the SW1-3 connection point on the stomp-switch board you may find that there is audio present but it is at the same level and quality as what is on pin 1 of IC1 (yes - IC1).
If this is the case and you cannot easily see any problems with the stomp-switch and PCB, replace them.
I disconnected/cut the wire SW 1-3. When I probe the half of the wire connected to the stompswtich SW1-3 I get the same audio as pin 1 on IC1, but there is no audio on SW1-3 on the full PCB board half of the wire. I think it actually grounds out.
Or you may have a short between the connection points 1.1 and 1.3 (SW1-1 and SW1-3) on either the main board or the stomp-switch board.
Quote from: Big mike 1100 on February 13, 2018, 10:34:11 PM
I disconnected/cut the wire SW 1-3. When I probe the half of the wire connected to the stompswtich SW1-3 I get the same audio as pin 1 on IC1, but there is no audio on SW1-3 on the full PCB board half of the wire. I think it actually grounds out.
SW1-3 is the output (terminal 2 - wiper) of the volume pot. Check the continuity and also check for ground shorts.
But you should not have audio from IC1 showing on SW1-3. Unless there is a short between SW1-1 and SW1-3 it can't be there.
Remember that when you cut the SW1-3 wire any audio that may be coming from IC2 (yes - IC2) pin7 will now be varied by the volume control. Turn the volume to maximum to ensure high level.
There is continuity between Volume terminal 2 and SW1-3 on the board
Questions:
1-There doesn't appear to be continuity between 1.1 and 1.3 which I would assume show that there's no short, correct?
2-are you saying there should be no audio on SW1-3 on the stompswitch? It's definitely there, just not affected by any of the pots.
3-Does this mean I should disconnect everything from the PCB stomp switch and start the switch connection over?
On the main board you should have "dry" audio (pin 1 of IC1) appearing on the 1.1 (SW1-1) connection point. This audio is not altered by the gain/tone/volume pots. It is used for bypass audio in bypass mode.
The 1.3 (SW1-3) connection point is the "wet" audio connection. This is audio that has been altered by the effect circuitry. Audio will only appear at this connection when the effect is engaged. When it not engaged (bypass mode) there is almost no audio at this point due to D1 and D2 being shorted to ground by the 2.1 (SW2-1) connection.
Quote from: Big mike 1100 on February 13, 2018, 11:02:08 PM
There is continuity between Volume terminal 2 and SW1-3 on the board
Questions:
1-There doesn't appear to be continuity between 1.1 and 1.3 which I would assume show that there's no short, correct?
2-are you saying there should be no audio on SW1-3 on the stompswitch? It's definitely there, just not affected by any of the pots.
3-Does this mean I should disconnect everything from the PCB stomp switch and start the switch connection over?
I suspect that there may be a short between 1.1 and 1.3 at the stomp-switch board.
Dry audio should always be present at 1.1 on both the main board and the stomp-switch board. However dry audio should not be present at 1.3 on either board in either bypass or engaged modes.
Thanks Slowpoke- I'll get another 3PDT switch as it's tough to successfully desolder the pcb board from the stompswitch and first try wiring without the small PCB bypass board and see how it goes. I'll report back in a few days.
My 3pdt switches finally came in and I was able to rewire it, but still having issues. I think I might actually be wiring it wrong. I first was using the Refractor bypass board, but I'll bet there are solder bridges under it and I didn't want it to happen again, so I followed the offboard wiring schematic found on page 7:
https://aionelectronics.com/project/refractor-centaur-overdrive/
Firstly, there is a 100K resistor (R28). The instructions say that if it's not put in the spot on the picture (between lugs 4 and 6 on the switch), that its easier to run it from the output jacks lug to the star ground.
Just to confirm:
this means running the 100k resistor from the Tip of the output jack to the star ground lug on the input jack. and if this is the case, does that brown wire still go from lug 4 on the switch to the output jack tip, which will also have one leg of the resistor on the same output jack tip?
And does the green wire on lug 6 of the switch still go to ground?
Using the audio probe- I get great volume up to R25, and then it's very quiet on Lug 2 of the volume pot.
Right now, when the guitar is plugged in, there's no sound in either bypass or when the pedal is on.
Please refer to the following picture to help avoid confusion. Note the position of the switch - the lugs (terminals) are horizontal.
(https://s18.postimg.org/bag8h2ait/Stomps_SW1.jpg) (https://postimg.org/image/bag8h2ait/)
R26 (68K) is connected to terminals 1 and 2.
R27 (68K) is connected to terminals 2 and 3.
The brown wire connects to terminal 2 and to the tip terminal of the output connector.
Terminal 1 connects to the 1.1 board connection point.
Terminal 3 connects to the 1.3 board connection point.
Terminals 4, 5 and 6 are left vacant.
Terminal 7 connects to the 2.1 board connection point.
Terminal 8 connects to the star ground point on the input connector's sleeve terminal.
Terminal 9 connects to the 2.3 board connection point.
Resistor R28 can be connected to terminals 2 and 8 but due to terminal 2 getting very crowded, R28 can be connected to the output connector's tip terminal and the star ground point on the input connector's sleeve terminal. Terminal 8 must still be connected to the star ground point.
A continuity test will help to establish that things are connected correctly. Test for continuity between terminals 1 and 2 then between terminals 2 and 3. Only 1 set will have continuity. Then click the stomp switch and test for continuity between the set that was open circuit, it should now have continuity and the set that did should now be open.
Thanks Slowpoke! All wired up as you explained. The continuity is still a bit of an issue
in one position of the switch
2&3 connect
1&2 do not
8&9 connect
7&8 do not
in the other position of the switch
1&2 connect
2&3 connect****strike that! found a stray wire. should be ok!
7&8 connect
8&9 do not
Just plugged it in and there's good news and bad...
The Good news is I'm back to where I was before with there being sound in bypass mode and also when the pedal is engaged. The only thing that works is the volume pot- no tone and no gain. I actually replaced the gain pot and the volume pot, as well as most of the wires, which were bending and breaking after so much movement. I have to figure out the best wire to buy, as what I have isn't very sturdy.
As long as: "2&3 connect****strike that! found a stray wire. should be ok!" in now OK, then the switch tests OK. Now for the wiring.
Apply power and make sure that the LED lights up in when the effect is engaged and goes out when in bypass mode. If it does then go to the next step. If the LED doesn't behave have expected then you have to find out why.
If all is good then remove power will in bypass mode (LED not lit). Test for continuity between board connection point 1.1 and the tip terminal of the output connector. If there is continuity click the stomp switch to engaged and test for continuity between board connection point 1.3 and the tip terminal of the output connector. If there is continuity then the major switch wiring is correct.
I just noted your last edit.
Damn. I was hoping that you were close to getting the effect to work properly. Oh well...
I will have another look to see if there is anything else that could be causing this problem.
would it make sense to
Make sure that the resistors and caps etc are the right sizes again? I've done it a few times, but will do it again if that could be the reason for the issue?
Or with the audio probe, is there a point on the board where gain and tone might work and then just stop working?
So the good news is that I got the pedal working. There was no connectivity between R25 and Lug 3 of the volume pot. I made the connection and all pots are working. There is a lot of static (like from an AM radio) and hiss though when the pedal is engaged but each pot works as it should, I believe. I'm not sure if it's a grounding issue or some other issue. All thoughts welcomed as to how to diagnose.
Thanks!
I sent you a PM (personal message) a few days ago that has a step by step procedure with expected results that may help you. Did you receive it?
Thanks Slowpoke- Being new to the forum, I didn't realize there was a message box. I'll print out your instructions and work on it tonight and tomorrow and report back with results.
Much appreciated!
Slowpoke- I finished your steps with a few issues and sent you a pm. I think the issues are stemming from IC2- perhaps pin 1 and 2?
So I pretty much have everything working with this pedal. It's really a fantastic distortion pedal and I highly recommend putting one together. It took me quite a while to debug, but I think that one big lesson had to do with the PCB board mounted Pots. When I thought they weren't working and replaced them, I think I might have broken internal connections in the board. I think it's pretty easy to do, since you can't just unsolder one wire at a time- I kinda heated a lug, pulled it out, heated another lug and pulled it out, etc.. I didn't remove all of the solder in each hole and had to take pliers and pull each one at a time which probably ripped some connections- In my case it was R25 to lug 3 of the volume pot, as well as the resistor that connects directly to lug 1 of the gain pot (can't remember which at this time, but you get the idea)- After using the audio probe and checking for connectivity, it was easy to spot, but took a while to get there!
My last issue is that when I strum a hard chord and Gain pot is turned fully, it yields a distorted clicking/choppy/helicopter noise and then settles to normal distortion as the chord rings. When its turned at 97%gain or less there is no issue.
Slowpoke, I know you mentioned that it could be a feedback or grounding issue. The pedal works perfectly except when the guitar is struck hard at 100% gain- Volume can be high or low and it happens. If I just lightly pluck a string at 100% gain, it also doesn't happen.
Any thoughts?
Quote from: Big mike 1100 on March 01, 2018, 10:29:18 PM
I think that one big lesson had to do with the PCB board mounted Pots. When I thought they weren't working and replaced them, I think I might have broken internal connections in the board. I think it's pretty easy to do, since you can't just unsolder one wire at a time- I kinda heated a lug, pulled it out, heated another lug and pulled it out, etc.. I didn't remove all of the solder in each hole and had to take pliers and pull each one at a time which probably ripped some connections- In my case it was R25 to lug 3 of the volume pot, as well as the resistor that connects directly to lug 1 of the gain pot (can't remember which at this time, but you get the idea)-
When you need to remove a part from a board that would be difficult to desolder, you may find it useful to think of it as choosing between destroying the board or destroying the part. In this case, snipping the pot off of its leads (choosing to destroy the part) would have made it easier to remove one pin at a time.
I know it's been a little while and I've built a few other pedals with the help of this forum, but something is bothering me with this pedal. When the gain is at about 3/4 (2:30 or 3:00) of the way and I strum a chord or pick a note with a slight attack, the pedal "stutters" until it quiets down again, almost like a delay pedal with too many repeats. It's not even a hard strum pick. Plus the distortion is not nearly as crunchy as other overdrive pedals. Could it just be a wrong/bad part somewhere?
Any thoughts? I can't imagine it's the way the pedal was designed.
still stuck on this one. Figured I'd try again. Thanks!
I think stability issues can creep in on that design when the gain is cranked too high (sometimes they can oscillate). As far as I know, none of them (stable or not) sound good as you pass that 3/4 mark.
Also, don't expect crunchy sounds from it. It's a mostly clean overdrive.