DIY disaster : No sound

[Yata]

It is never something obviously visible, otherwise we'd fix it right away. If you can post large clear sharp pictures of the solder side of the board we might be able to spot something. Also make sure those exposed components leads aren't touching something they shouldn't. But the measurements don't lie - pins 1 and 2 as you call them - emitter and base - are shorted to ground - thus the lack of signal beyond C12. I would carefully remove R22 and R23 and see if they are still shorted, and check that those resistors are okay.

Also - the negative side of C13 should not connect to ground - so something around the volume pot is wrong. This may be shorting the output to ground as well.

Weird thing, I am still getting sound through the middle pin of Q4 which is attatched to C12 but no sound from C12 itself, the top of r22 goes to the middle pin of Q4  as well so I assume thats where the sound is coming from?. I'll try to remove those two resistors and take some photos when I get a chance, same with the volume pot.

I'm still sort of confused about these circuits but is it the understanding that these bottom resistors on the schematic stop the guitar signal from being grounded and so there is a chance something around these resistors is causing the grounding?

[GGBB]

Weird thing, I am still getting sound through the middle pin of Q4 which is attatched to C12 but no sound from C12 itself, the top of r22 goes to the middle pin of Q4  as well so I assume thats where the sound is coming from?.

That makes no logical sense. The point where C12 and Q4 base (middle) join is electrically a single point, so it cannot have sound and no sound at the same time. Unless the two are not actually joined. Bad solder? Hairline crack it the trace?

I'm still sort of confused about these circuits but is it the understanding that these bottom resistors on the schematic stop the guitar signal from being grounded and so there is a chance something around these resistors is causing the grounding?

I suppose you could say they do that, although that is not the intended function. That statement sort of implies that somehow the signal will ground itself unless preventative measures are taken, which isn't the case. A signal will only be grounded if it is deliberately (or accidentally) connected to ground. (Of course that's a very simplified way to look at it because the signal only exists relative to a reference point which is usually ground.) The intended function of R21 and R22 is to set the DC voltage at the base of Q4. The intended function of R23 and R24 is the set the DC voltage bias of the transistor as well as the gain. All four ensure that the transistor works properly.

[Yata]

It seems I'm getting nowhere fast lol. after leaving it a few says then unsoldering R22 and R23, I am not longer getting ground on both sides (Im guessing this is obvious) but it seems im getting ground continuity in a whole load of places I didnt realise before.  I'm now getting ground on all of my Pot lugs and also lug 1 of my mini board mounted switch.

Its def something on the board itself as when the 3PDT is pressed true bypass it working fine and nothing is grounded. Also the no1 wire from my board that connects to no2 and bypasses hte octave effect is showing no ground but no2 is showing ground.

I'm just confused as hell here.  I basically have no idea what I'm doing here to try and find out why Im getting no sound, I wonder if its best to just give up on this and try a new kit next month for a different pedal. My local guitar shop has a cheap chinese clone of this in stock, it might not be as high a quality but it will do I'd imagine. My reverb kit seemed to go without a single hitch (worked perfect first time) and I'm not sure the vast amount of time I'm spending trying to diagnose this is actually getting anywhere.

Pictures: http://imgur.com/a/2D2Zu

[EBK]

That's not a solder bridge at the top of the "U", is it?

Lots of dull-looking ball-shaped solder joints....

Are you heating the pads on the board, and applying solder to the joint itself and not the iron?  It's looking like you may be burning off your flux before the joint is made or not heating the pad along with the wire/component leads.  Just guesses since im not standing over your shoulder while you solder.

[Yata]

So I decided to come back to this a month later once I had a new PCB in my hand, pulled a few caps and bought some fresh components and soldered them all in. I deliberatly left out hte daughterboard and jacks and just wired the DC in and the mainboard. Problem is, before I even plug it all in, I'm getting continuity with ground, EVERYWHERE. I think there are maybe a handfull of points on the board that aren't getting some sort of continuity with ground. I've tried my best with the solder joints, no obvious bridges I can see (I slid peices of card in between every solder joint to make sure) and I just can't figure out what is wrong.  Could I have damaged a capacitor removing them from my old board? can a damaged capacitor cause the entire board to go to ground?

I've also tried removing the diodes/trannies and middle pot, it makes zero difference

It seems like terrible luck this has happened twice but the reverb pedal I built worked first time. So my question is, what have I done wrong and what could cause this level up buggery on the pcb.

https://imgur.com/a/cz4mz

[EBK]

Let's get a few things out of the way:
What kind of meter are you using and what setting do you have it on?
You are measuring without power being connected, right?

As far as damaging components by soldering/desoldering, I think it is definitely a possibility.  What kind of soldering iron are you using?  Are you by chance using a lead-free solder?  If not, then dullness of those joints suggests a soldering problem that we need to address.

By the way, don't use the rivets on the pots as an electrical connection point.

[Yata]

Let's get a few things out of the way:
What kind of meter are you using and what setting do you have it on?
You are measuring without power being connected, right?

As far as damaging components by soldering/desoldering, I think it is definitely a possibility.  What kind of soldering iron are you using?  Are you by chance using a lead-free solder?  If not, then dullness of those joints suggests a soldering problem that we need to address.

By the way, don't use the rivets on the pots as an electrical connection point.

Just a normal cheapo multimetre on the continuity setting. I'll attatch a photo.

https://imgur.com/a/Lcf8G

I've already cut the wires to that middle pot and I still have problems.

You are also correct in that I havent wired up any power or jacks yet because I wanted to check for contuinity as you can see earlier in the thread the problems I've had with the last one I built.
It is also lead-free solder, I can't get ahold of other stuff and I'm not too comfortable having lead around in a household with pets and small children. Would a cold solder joint result in my entire pedal grounding and no sound though? like afaik surely a cold joint would just stop current from passing a certain point right?

[EBK]

It is also lead-free solder, I can't get ahold of other stuff and I'm not too comfortable having lead around in a household with pets and small children. Would a cold solder joint result in my entire pedal grounding and no sound though? like afaik surely a cold joint would just stop current from passing a certain point right?

I mostly asked about this because I was worried you may have been overheating things by taking too long to make connections with an underpowered iron (so, a cold joint problem indirectly, if that makes sense).  Now that we have a reasonable excuse for dull-looking joints (the normal appearance of a lead-free joint), I can stop being distracted by that. 

[EBK]

You are using a diode check mode on your meter, not a continuity mode.  The displaying is showing what the meter estimates is the forward voltage drop across the diode it assumes it is measuring.
(Actually, looking at the numbers on the display, I have no idea what it is showing....)
If it beeps, it is just to tell you that your "diode" is conducting.
Try your lowest resistance measuring setting instead.

[Yata]

You are using a diode check mode on your meter, not a continuity mode.  The displaying is showing what the meter estimates is the forward voltage drop across the diode it assumes it is measuring.
(Actually, looking at the numbers on the display, I have no idea what it is showing....)
Depending on how it does this, it could be the equivalent a continuity test or not....
Try your lowest resistance measuring setting instead.

I apologise for my assumption but it was only after posting several times on the DIY pedal section on reddit for help, people kept telling me to use a continuity setting and I didn't know what it was (they kept talking about a beeping noise). Eventually after posting pictures everybody assured me that it was the setting in the previous pictures. If this is a wrong assumption it could throw everything out.

One thing that does happen though, is that when I use what I thought was the continuity mode it normally starts with a really low number (002/004 ect.) then climbs higher.
There is also no speaker on the multimeter 100%, no sounds, nothing like that.

I geniunely feel lost here, I never had a single problem like this with my reverb pedal. I know my soldering skills are not great but can they really be that bad that the entire pedal is unusable. I've done a few mods to pedals I own in the past and also never had problems like this.

The lowest section on my ohm's is 200, what would I go about testing here and what information would be usefull to you? Am I looking for a certain number range ? I feel like I'm back at square one but I'm willing to test every component if it helps.

[GGBB]

Continuity is an on-off thing - you either have it or you don't. It is zero resistance (in practice very close to zero). Not all meters have a continuity setting, and some that do have it as part of the diode setting or the resistance setting. On one of my meters, all three are the same setting with a momentary button to cycle through each function.

If you don't have a continuity setting, just measure resistance on the lowest range and watch for zero.

[EBK]

I geniunely feel lost here, I never had a single problem like this with my reverb pedal. I know my soldering skills are not great but can they really be that bad that the entire pedal is unusable. I've done a few mods to pedals I own in the past and also never had problems like this.

If it helps, I no longer think it is a soldering problem.  The lead-free question cleared that up for me.

[Yata]

Continuity is an on-off thing - you either have it or you don't. It is zero resistance (in practice very close to zero). Not all meters have a continuity setting, and some that do have it as part of the diode setting or the resistance setting. On one of my meters, all three are the same setting with a momentary button to cycle through each function.

If you don't have a continuity setting, just measure resistance on the lowest range and watch for zero.

I don't have more time today unfortunately because I'm going to my first rehersal in a decade (was hoping to have this pedal ready lol)

But tommoro I am going to take the value on my MM at EVERY point in the circuit and write them all down. Hopefully that can give me a better picture on what is going wrong..

[duck_arse]

set yr meter on the 200R range, and hold the two meter probe tips together. what does it read, 000, or some very low number? that is zero ohms, a dead short, on your meter. anything you probe that shows a number greater than your zero reading is not a short.

I think all the readings you've done on the diode setting look reasonable. again, you can short together the meter leads while in "diode test" range, see what that reading is - that would be the number indicating a dead short diode, or transistor. other numbers as you've presented are "some number of millivolts", indicating "some component more resisting than a short circuit is between my probes".

[PRR]

> telling me to use a continuity setting

Continuity is for trailer-light mechanics, for quick beep-tests.

On many meters, anything over 50 Ohms is silent, anything under 50 Ohms is BEEP. The 50 ohms is arbitrary. In trailer-lights, it kinda rough-sorts the bad connections from the good connections.

Is also maybe handy for quick-checking electronics, BUT in electronics we DO have important readings both below and above 50 Ohms.

> starts with a really low number (002/004 ect.) then climbs higher.

That's why we electronics techs (including you) want the numbers, not the beep. Big capacitors DO act like low-Ohm short at first, then charge-up to a near-infinite Open. If you have the capacitors soldered, at many points on the board you expect the Ohms number to start low and then go high. If you have resistors onboard, it won't go any higher than some resistor. Some insight, or allowance for not-knowing, still helps you sort the good, bad, and maybe readings.

[Yata]

Thanks again for hte replies guys, Ive not had time all week to work on this due to work apart from today. I took some various readings but the numbers I got in return just seem to confuse me more. I think my multi-metre might actually be junk now as nothing seems to make sense. When I test it shorted, as in both tips touching it starts at 00.0 then climbs slowly 0.1 at a time. Given the readings and buggery with my MM I assume its totally not safe to wire everything up to the Dc jacks and test it again. Can anybody think of any more measurements I can take to get me further? The readings I tested were all on components I thought from the circuit obviously looked connected to ground.

All values read from the OHM 200 setting on multimetre

9v Dc to ground on PCB = starts at 0 then climbs up (when measures on the 200k setting shows different values from 1 to 2.5, seems to keep climbing)

D7 to ground + side 11  - side 40 // Across: starts at 30 then climbs up past 200 before going blank

C11 to ground : side closest to pcb starts at 0 then climbs higher -side furthest away: starts at 40 then climbs higher  resistance across: starts at 0 then climbs

C2 to ground : side closest to pcb starts at 0 then climbs higher- side furthest away: starts at 40 then climbs higher  resistance across: starts at 0 then climbs

R5 to ground : side on pcb edge, starts at 0 climbs higher slowly- side furthest away: starts at 100 then climbs past a detectable setting


C8 to ground : side closest to pcb starts at 0 then climbs higher - side furthest away: starts at 0 then climbs higher  resistance across: starts at 0 then climbs but cant seem to find hte point it stops

[Yata]

Yesterday was payday so my plan is to buy a new multimeter from Maplins with proper continuity testing mode and go to town on this baby. Hopefully it reveals something.

[EBK]

Yesterday was payday so my plan is to buy a new multimeter from Maplins with proper continuity testing mode and go to town on this baby. Hopefully it reveals something.

I'd recommend learning to do more with the meter you presently have.  You can measure continuity just fine in resistance mode with yours.  Besides, if you are certain your power supply isn't shorting out, you might be better served measuring some voltages....

[Yata]

That's the problem, im not sure if it's going to short or not because I can't interperate the readings from my multimeter

[EBK]

That's the problem, im not sure if it's going to short or not because I can't interperate the readings from my multimeter

This is a problem that a new meter won't fix, so let's slow down and address this.

First, let's slowly walk through the steps of determining whether your power supply would short out.  (Some basic resistance measuring)

I'll post this first, and re-edit it step by step, in case you're reading along... 

First, you need to know thar you have a manual range meter.  What that means is for measuring things like resistance, you will have to look at the reading on the display to determine whether the setting is correct or whether you need to turn the dial to a different range to get a proper reading.

1. Start on your lowest resistance setting, which is one click clockwise from that diode setting.  In your case, that is the 200-ohm setting, which is for measuring resistance values from 0 to 200 ohms.

2.  Without the probes touching anything, your display should show something that isn't a number.  Probably something like "E" or "OL".  This is your out-of-range indication, which means that the resistance between the probe tips is something greater than 200 ohms. 

3.  Now touch the probe tips together.  The display will read "0", or at least something darn close.  Because you are in the lowest range setting, you can interpret this as 0 ohms, the equivalent of measuring the resistance of two points directly connected by a wire.  If, however, you were in a higher range setting (like 200k, for example), this "0" would be another out-of-range indicator, meaning it is too low to measure in the present setting, and you would need to select a lower range to take the measurement properly.

4.  Now, if all is well with your power connection to your board, we would expect a resistance value between the positive voltage supply and ground connection points to be pretty high, something definitely above your 200-ohm lowest meter range.  Always measure resistance without power connected to your circuit under test.   If you go ahead and measure those two power supply points on your board, your meter display should hopefully stay the same, indicating out-of-range.  Don't worry if it temporarily changes at the moment you first touch the probes yo the board.  We are looking for the settled, steady-state reading.

5.  At this point, set your circuit board aside and grab several different resistors from your parts bin, if you have some available, and practice measuring.  This practice will help tune your meter interpretation skills. 

(I taught Sophomore- and Junior-level circuits lab classes in grad school, by the way, so I've walked dozens (hundreds?) of people through this before.   )


By the way, let's follow Paul's advice and completely forget about the concept "continuity" for the moment.  All you really need to know about that is "checking for continuity" is a rather imprecise way of saying that you are measuring resistance and seeing if it is relatively low.

Ok, I'm done editing this post.