Hey guys
Built the DS1 today and not getting any output when engaged. Got sound from the bypass but just nothing from when engaged.
When it is engaged, gain on full whack I can definitely hear louder hiss, and the tone and volume seem to be doing things but there is just no sound...
IC voltages look like this:
battery: 9.03v
8.45 9.03
8.49 8.10
8.57 8.48
8.92 8.47
Q1
E
8.88 6.10 9.03
Q2
E
8.98 8.23 8.95
Q3
E
8.84 4.42 9.03
Im using a DPDT 'wiring 1' from tonepad just for testing purposes as its easy to wire. will put in the led later.
Diodes are 1n4148 (original 1n914)
Transistors are TL072
Tonepad project: http://tonepad.com/getFile.asp?id=78
Tonepad wiring http://tonepad.com/getFile.asp?id=76
Please help, really want this one to work!
(http://havsingh.com/Guitar/DS1%20Tonepad.JPG)
Thanks :-)
WHOA your voltages are far too high! Something is wrong - could you have made a 'solder bridge' between adjacent pins, or components?? Look at where the power goes into the board - everything ok there? Check pin 4 of the IC - ground (battery "-") and that pin should have continuity, as anywhere else that is grounded - you should NOT have ~9V there, so that's indicating a short somewhere....
Ai ai ai ai aeeeee! Go back thru the solder joints with (literally) a magnifying glass. If you can, post a pic of the BACK of the board, too. Your transistor voltages are way off, too, so the problem seems "systemic" and not limited to just the IC.
BTW, did you mean the IC is a TL072? What are your transistors?
The 4148's are direct subs for 914's, no worry there.
Typically, if you can find the short(s) and correct them, you're probably ok. Might have toasted the IC, Q's or what have you, but we'll deal with that at the proper time ;) These mistakes are the most common, so don't sweat it.
Quote from: GibsonGM on August 15, 2014, 06:25:14 PM
. . . post a pic of the BACK of the board, too.
And please get it the right way round! ;) The picture you posted of the topside is a reflection! :icon_eek:
Ah thanks for the replies guys will update pics, on my phone ATM can't get onto tonepad to check Transistors but it's the ones that they asked - 2n5088 or something like that. Sorry - IC is TL072. I did find one solder bridge and have removed it but I believe I've already blown IC. It's odd I do remember having the values almost at half those and 0 at pin 4 but then I tested again and those above are what showed. Will do a proper search again for bridges and report back. Will the transistors have gone too? Can I use a 4558 as I'm now out of TL072?
look what you've done to gibson .....
flip the image, remove the IC, measure the voltages again. and please tell the Vbias (or what it might be called this instance) volts.
this reminds me of the time the circuit had no earth connection or something, and the dmm was just floating all the measures to ~9V. who else remembers that one?
Quote from: duck_arse on August 16, 2014, 11:05:30 AM
look what you've done to gibson .....
flip the image, remove the IC, measure the voltages again. and please tell the Vbias (or what it might be called this instance) volts.
this reminds me of the time the circuit had no earth connection or something, and the dmm was just floating all the measures to ~9V. who else remembers that one?
I'm ok now, Duck! :)
You may have ruined the transistors, hard to say. Remove them too, please, and measure all voltages on all pins for them and the IC. And like Duck suggests, find the Vbias and read that too, ok? Black probe on "-" of battery, use the red to measure - sorry if you already know that.
A 4558 can sub in for the 72, yup, but wasn't in the original so eventually you'll stick a new 072 there. You should try to get a bunch of stuff for your parts bin, like 10-20 2N5088's, and such. If you have a decent DMM, we can tell you if the transistors are ok - does yours have a 'diode function'?
Hey guys, sorry for delayed reply!
So as per requests:
Image flipped correctly above.
Found only 1 short, now cleared.
Removed all Transistors and IC, put negative to ''-'' on battery and ''+'' on relevant points:
Battery: 9v
IC
0 9
0 0 (starts at 4ish then rapidly reduces)
8.6 0
8.9 0
Q1
E
8.8 6 9
Q2
E
8.9 8.1 8.9
Q3
E
8.8 4.4 9
Vbs
almost all 8.9v, think 1 was 8.8
I have a DMM, it has a 'diode' image on it, but not too sure how to use this to test transistors... it doesn't have any audio beep feature however.
Oh, tried another TL072 with the same transistors, and am getting the same voltages. probably just blew another one :-(
Spent last hour triple checking solders etc and cant see any other bridges :-(
Quote from: Hav on August 17, 2014, 04:27:20 PM
IC
0 9
0 0 (starts at 4ish then rapidly reduces)
8.6 0
8.9 0
You have (almost) 9V on pin 4. This should be zero. You still got a short somewhere? Is the battery warm? Can you do us a photo of the underside of the board?
The battery is ok, tested in other circuits and its good. I have taken the best pics i could here, might need to use a better camera (using phone atm) and some propert lighting, but hopefully this will help...
Just to confirm, where it says 'empty' on tonepad's site, it means just literally leave them empty, not place jumpers or anything in place?
also you will see from the soldering, im still learning!
http://havsingh.com/Guitar/DS1/DS1%20Back%202.jpg
http://havsingh.com/Guitar/DS1/DS1%20Back.jpg
Thanks!!!
Way to know if you have a nice-size short is to plug the battery in, then measure voltage across it...if it starts dropping more than a tad, you know you're shorted. Remove batt. or it will die ;)
Ya, empty means empty, no jumper. That voltage on pin4 really says power supply short...your solder may be ok, but you have to be sure all your wiring goes to the right places!! If it's wired correctly, it WILL work!
Battery doesn't dip when plugged in :-( quite solid at 9v...
I will go over the entire layout for the second time, hopefully i'm just missing something, just can't see it! i'm quite certain there are no more shorts, but again, could also be missing something so obvious, maybe someone here will pick it up..
Thanks for the help so far!
making me think ive used the wrong dpdt wiring diagram. is there a 'standard' diagram people use?
I habitually use #3 or #5 from the Tonepad wiring doc (in your post), depending on whether I'm using a Millennium-2 or a 3PDT. Works like a dream.
Have you tried checking continuity at various points on the board? Set your meter accordingly, put one probe on the battery clip "-" (without the battery connected) and check all points on the board (and on your jacks) that are supposed to be "ground" (green on the tonepad diagram). Now do something similar with battery clip "+" and all the 9V points (red on the tonepad diagram). Now (or first!) check that there's NO continuity from the battery clip - to +. Also: with the battery connected, the pink VREF trace should be 4.5V.
there is 2 x 6k8 resistors at the top o' the board. what values do you have fitted there? and that 68nF at C2, not 470nF?
Quote from: duck_arse on August 18, 2014, 10:54:30 AM
there is 2 x 6k8 resistors at the top o' the board. what values do you have fitted there? and that 68nF at C2, not 470nF?
I've used 6.5k resistors as didn't have any 6.8k left... and yep I followed the 'TL072' parts guide so used the 0.068uf / 68nf cap there...
Quote from: bluebunny on August 18, 2014, 10:37:48 AM
I habitually use #3 or #5 from the Tonepad wiring doc (in your post), depending on whether I'm using a Millennium-2 or a 3PDT. Works like a dream.
Where do I get this 'millennium board' from? I'm using Diagram 1, I assume that should work just fine for now?
Quote from: bluebunny on August 18, 2014, 10:48:33 AM
Have you tried checking continuity at various points on the board? Set your meter accordingly, put one probe on the battery clip "-" (without the battery connected) and check all points on the board (and on your jacks) that are supposed to be "ground" (green on the tonepad diagram). Now do something similar with battery clip "+" and all the 9V points (red on the tonepad diagram). Now (or first!) check that there's NO continuity from the battery clip - to +. Also: with the battery connected, the pink VREF trace should be 4.5V.
I did do a few tests last night, and it all looked good. I will follow your steps in a few hours and report back the results. I feel I may have wired it up wrong, i've never used a DPDT switch before, but followed instructions. Again, will double check it all and get more pics up if I can't find any more problems..
If diodes are blown will that cause any of these problems? how can i test this?
right!
im getting '1' on my DMM when I try and find continuity on the negative side of things... I assume that means there is nothing happening! Positive rail is all good! Where to look?!
If you are reading 8.9V on Pin 4 of the IC when it is removed.... YOU HAVE A SHORT BETWEEN V+ (9VDC) and GND SOMEWHERE!
Remove power from the circuit and remove the IC. Put the DMM black lead on the Pin 4 spot. Put the red lead on the Pin 8 spot. Tell me how many ohms you are reading.
I am willing to bet it is less than 50 :o
Somewhere you have a short and need to locate it ;)
EDIT: Quick tip.... check to make sure you wired your Input jack correctly for battery shut off..... if you are using a battery ;)
Quote from: Govmnt_Lacky on August 18, 2014, 03:33:56 PM
If you are reading 8.9V on Pin 4 of the IC when it is removed.... YOU HAVE A SHORT BETWEEN V+ (9VDC) and GND SOMEWHERE!
Remove power from the circuit and remove the IC. Put the DMM black lead on the Pin 4 spot. Put the red lead on the Pin 8 spot. Tell me how many ohms you are reading.
I am willing to bet it is less than 50 :o
Somewhere you have a short and need to locate it ;)
EDIT: Quick tip.... check to make sure you wired your Input jack correctly for battery shut off..... if you are using a battery ;)
yep your right! I definitely have less than 50! its at 0!!! if i set it too '200m' on DMM i get 0.02!!
Where else can this short be? can it be a dodgy switch / wrong way round transistors?
Quote from: Hav on August 18, 2014, 03:38:37 PM
Quote from: Govmnt_Lacky on August 18, 2014, 03:33:56 PM
If you are reading 8.9V on Pin 4 of the IC when it is removed.... YOU HAVE A SHORT BETWEEN V+ (9VDC) and GND SOMEWHERE!
Remove power from the circuit and remove the IC. Put the DMM black lead on the Pin 4 spot. Put the red lead on the Pin 8 spot. Tell me how many ohms you are reading.
I am willing to bet it is less than 50 :o
Somewhere you have a short and need to locate it ;)
EDIT: Quick tip.... check to make sure you wired your Input jack correctly for battery shut off..... if you are using a battery ;)
yep your right! I definitely have less than 50! its at 0!!! if i set it too '200m' on DMM i get 0.02!!
Where else can this short be? can it be a dodgy switch / wrong way round transistors?
oops, ohms being resistance lol - yep is 19.2 :icon_confused:
Pics of the ENTIRE board (component side, trace side, and offboard wiring) will help a lot.
Also... is this circuit OUTSIDE of the enclosure?
yes circuit is outside enclosure... ok will get some pics up...
Ok here are some more pics:
http://havsingh.com/Guitar/DS1/Ref%20Files/
Hope they are good enough, if you need others please let me know!
Warning: There's at least 3 problems.
1) pin 4 is not (well) connected to ground, or it wouldn't be able to lift up to (almost)9V. It should be dead shorted to ground.
2) pin 4 is, as found, somehow shorted to 9V.
3) Vref is wrong somehow. it should be at half supply voltage, but it is also at full voltage - pin 3 is connected to Vref, but showing (almost) 9V.
After that is sorted, it may well be the transistors bias up nicely. If not, time to dig deeper.
yep I just can't find how its shorting... i literally cannot see any shorts whatsoever. although its clearly there somewhere lol. can it just be a dud IC socket? can you even get dud IC sockets ?
Also, DPDT says 1, 2, 3 on one side. I totally didnt see that before.. related? I just thought these things can go either way (as long as its like this:
| |
| |
| |
Your DPDT looks good.
I recommend taking an xacto knife and using it to isolate the entire +9V trace from the rest of the circuit. What I mean is that you "scratch" between the entire 9V trace and any other nearby traces for the entire length. This way... even if there is a micro short... you will break it.
If that doesn't work, I would check(On the COMPONENT side) that every point that is supposed to connect to Ground is connected. Make sure they are shorted. This will check for cold solder joints.
Report back if none of this works and..........
Good Luck ;D
Ah thanks I will give this a try! By '..connect to ground is connected ..shorted' how do I do this exactly?
OH MY! I don't feel silly...
Plugged Jack in to input and voltages completely changed. Note to self.. DAMN IT :-s
Anyhow, so now voltages look better, but still no sound. The only thing that looks off its Q2.
Here are some figures:
Battery 8.8
IC
4.4 8.8
4.4 4.3
3.8 4.4
0 4.4
Q1
E
3.3 2.7 8.8
Q2
E
0 0.6 0.9
Q3
E
2.9 1.9 8.8
now to battle this No Sound problem? Q2 doesnt look right, swapped Q3 with Q2 and got the same figures so I assume they are functioning correctly... ?
again, I can hear volume tone and gain increase and decrease. Bypass works. just no engaged sound...
From the looks of it, Q2 is not getting power, which should be near 9V.
Q1 and Q3 are screwy in that your emitters are more positive than base, which is 'not possible' (at least in order to function, ha ha). E should be about .5 to .7v lower than the base - see how it's .6 lower on Q2?
Take this a step at a time...you need to find out why your emitter at Q1 is more positive than base, and then trace back from collector of Q2 and see why no power...take it a step at a time. Hopefully there will be one problem that, when corrected, will take you up to the IC. Maybe.
I suspect a bad component VALUE somewhere in that area....too high of a resistor or something that was accidentally installed rather than the right value....your Vref looks good at the IC, anyway, so let's find out why it's not near 4.5V at Q1's base....you should get Vref at the base of Q1, GND after the emitter resistor, and ~9V on the collector. Once that's set, we'll move to Q2! Short or part value....track it down! ;)
Thanks Mike!
I will get on this tonight, but before I do,
just want to confirm that I have these Transistors in the right way:
Datasheet: https://www.fairchildsemi.com/ds/MM/MMBT5089.pdf vs my layout on the first post...
I think I have it right, but last time I thought I had it right and was totally wrong (apparently these pinouts don't mean much).
Right, so yep, found a 22R instead if 2M2 (bottom left of the image in first post). !!!!
Thats given me a distorted sound.
The Qs still gave the same readings, so I thought lets just flip em round (i'm finding different pinouts for the same transistor!!)
Now, I assume its correct:
Q1
E
0.68 1.15 8.88
Q2
E
0 0.6 5.29
Q3
E
0.35 0.88 8.88
do these look about right?
Quote from: Hav on August 19, 2014, 03:58:57 PM
do these look about right?
Is the pedal working? ;)
well yep suppose it is lol! that '0' is just making me think. but
THANKS EVERYONE! :-) now to box! :-)
Great! The voltages look very nice from here :) Glad you were able to get it going!!