DIY disaster : No sound

[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

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.

The problem is, when I was touching the two leads together I wasn't getting 0, I was getting a really low to zero number that climbed up eventually to a way higher number as if it was a capacitor, I just couldnt figure out what i was seeing as almost every test I did the numbers changed wildy.

I've went out and bought a replacement MM with a contiunity tester and immediately I've noticed it doesn't have this problem,I know you suggested not to do that but it was driving me up the wall. The new MM beeps when there is contiunity and shows a proper value for resistance, so I've taken some measuremeants to see what was right and wrong from the last MM. (remember hte last Mm was showing the same number as the two probes touched together on several components with ground.)

After retesting I have the following:

Vin and Ground = No contiunity (great, I can think about wiring it up now I reckon)
Input and ground = No continuity (the last Mm was showing continuity)
Output and ground = Continuity (damn)]
2nd and 3rd leg on the volume pot and ground = Continuity
Other pots inc 1st leg of volume =No Continuity with ground
Output 1 and 2 (for hte octave footswitch) and ground = no Continuity
C14 and ground = anode //NC  cathode//Continuity
D7 and ground = anode//Continuity cathode //NC
Q 4 transistor = Bottom two pins = Continuity top pin = nc
Q1 and Q2 = NC
Q3 = left pin -Continuity, other two pins - NC


IDK if any of this information is usefull to you, but on my last board it was around Q4 that I lost my sound right before the volume pot.
Also these are all measurements without the diodes anmd trannies socketed, but I have also tried different transistors and diodes on the last PCB incase it was a transistor failure (it wasn't)

[EBK]

I can see by your new meter purchase and your use of the word "continuity" 13 additional times that you're somewhat resistant to suggestion.     That's ok.  We'll go with it.


By the way, this...

Output and ground = Continuity (damn)]
2nd and 3rd leg on the volume pot and ground = Continuity
Other pots inc 1st leg of volume =No Continuity with ground

just tells me that your volume pot is probably turned all the way down.

[Yata]

I can see by your new meter purchase and your use of the word "continuity" 13 additional times that you're somewhat resistant to suggestion.     That's ok.  We'll go with it.


By the way, this...

Output and ground = Continuity (damn)]
2nd and 3rd leg on the volume pot and ground = Continuity
Other pots inc 1st leg of volume =No Continuity with ground

just tells me that your volume pot is probably turned all the way down.

yes, it's starting to dawn on thick old me that this might be the case, as I speak I'm trying to wire it all up then connect a battery to check, im still getting grounding at Q4 but lets just see how this goes. I think all the crazy read outs from my last MM had me confused because my last circuit I wasn't getting sound no matter how i turned the pots

And again, thanks for staying with my crazy head through this, I feel like some of this is finally starting to stick. If I used the word beep instead of contiunity would it help lol I understand what  you are saying about low resistance and continuity with ground but at this stage I'm just using the term incorrectly as a throwaway to mean 'the damn MM is beeping'

[EBK]

If I used the word beep instead of contiunity would it help lol I understand what  you are saying about low resistance and continuity with ground but at this stage I'm just using the term incorrectly as a throwaway to mean 'the damn MM is beeping'

As long as we understand what each other is talking about, any terminology is fine.  You can keep using the word "continuity", and I promise to stop counting.   
I'll have to take another look at the schematic before I can say anything about Q4, but I need to get some coffee and do some other work in the meantime.  What kind of meter did you get, by the way?

[Yata]

If I used the word beep instead of contiunity would it help lol I understand what  you are saying about low resistance and continuity with ground but at this stage I'm just using the term incorrectly as a throwaway to mean 'the damn MM is beeping'

As long as we understand what each other is talking about, any terminology is fine.  You can keep using the word "continuity", and I promise to stop counting.   
I'll have to take another look at the schematic before I can say anything about Q4, but I need to get some coffee and do some other work in the meantime.  What kind of meter did you get, by the way?

N19BW digital multimeter from maplins, it has their own branding on the box and it was the one they were using in store to test stuff.

[ElectricDruid]

What kind of meter did you get, by the way?

N19BW digital multimeter from maplins, it has their own branding on the box and it was the one they were using in store to test stuff.

You can do a lot with a decent basic multimeter. I had a digital multimeter from Maplins that I bought when I was a teenager in the 1980's. It finally gave up the ghost this summer!

T.

[Yata]

So I wired everything up and connected my 9v power supply. I took a few readings and it seems im getting no audio past Q2/D1. Good news is at least it powers on and no shorts to my 9v.

Q1-7.66
-2.21
-1.61

Q2-2.21
-0.74
-0.14

Q3
-
-0.58
-

Q4

[ElectricDruid]

Are those solder joints ok? I know there was a big discussion earlier about it, and we decided that it's lead-free so it all ok that they're dull.. but those mostly seem not there.
I expect the solder to wick through the holes for most of the joints, and certainly for ones where the component lead doesn't tightly fill the hole. That seems to have happened _rarely_ on your board. This suggests to me that you're not heating the joints enough.
Look at the switch and the pots, but the resistors are mostly the same.
I don't want to see huge blobs of solder over everything (Ugh! Nothing is worse!) but I want to see evidence that the solder has "flowed" into the joint. This requires all the parts of the connection to get to the required temperature. If you're using lead-free solder, that makes that a bit more difficult, since the required temperature is higher - either more time or a more powerful iron is required.

Ok, second opinion required from someone else. I don't expect you to believe it just 'cos some dude on the internet said it. That would be a *very* dangerous precedent to set, in general!

HTH,
Tom

[Yata]

Are those solder joints ok? I know there was a big discussion earlier about it, and we decided that it's lead-free so it all ok that they're dull.. but those mostly seem not there.
I expect the solder to wick through the holes for most of the joints, and certainly for ones where the component lead doesn't tightly fill the hole. That seems to have happened _rarely_ on your board. This suggests to me that you're not heating the joints enough.
Look at the switch and the pots, but the resistors are mostly the same.
I don't want to see huge blobs of solder over everything (Ugh! Nothing is worse!) but I want to see evidence that the solder has "flowed" into the joint. This requires all the parts of the connection to get to the required temperature. If you're using lead-free solder, that makes that a bit more difficult, since the required temperature is higher - either more time or a more powerful iron is required.

Ok, second opinion required from someone else. I don't expect you to believe it just 'cos some dude on the internet said it. That would be a *very* dangerous precedent to set, in general!

HTH,
Tom

I can certainly try to reflow any solder joints when I have a chance tommoro, anything that might work I'll try. I think the bad LED lights from my phone camera makes some weird looking shadows though, there are some parts that look fine IRL but look almost empty on the photo. Also the most recent photos are obviously on the side where I didn't solder but I understand what you mean, you would expect all the hole at least to be filled in.

[ElectricDruid]

Yep, fair enough - phone cameras and lighting can be a bit weird. It often seems very difficult to get stuff like this to come out on a photo like it is in real life.

Reflow where you think appropriate and see if it makes any difference.

Tom

[PRR]

> I was getting a really low to zero number that climbed up eventually to a way higher number

Any time a digi-meter gives strange readings, *change the battery* !!

You would think a meter, of all things, could show a LO-BATT error alert. But far too often, my meters have gone wonky without any hint of battery weakness. Maybe they drop digital-bits and don't notice; maybe the 1.250V reference starts dropping 1.1V 1.0V 0.9V; maybe the input buffer gets cramped-up.... who knows?

And yes, the way they throw-together fairly complex meters for $3 e-retail (but $13 in stores), it could just be a factory defect finally failed.

[Yata]

Yep, fair enough - phone cameras and lighting can be a bit weird. It often seems very difficult to get stuff like this to come out on a photo like it is in real life.

Reflow where you think appropriate and see if it makes any difference.

Tom

I basically went over every single joint on the PCB, held the iron tip (as hot as it couild go) till the solder melted again and visably went down in leve (as in flowed throughany remaining gaps) and did the same with the 3 pots.
Unfortunately  that didn't help and I'm still getting the same voltage readings at the tranny pins.
Does anyone have any suggestions as to other voltages I could take that could maybe indicate what is wrong or if there is a defective part?
The top 2 lugs of the switch are bleeping with ground as well

EDIT: on going through the bleep test once more, I'm getting bleeps on both side of R10 with ground and on both sides of D5/D6 with ground. I'm also getting beep on BOTH the anode and cathode of C9 which is very strange, and contiunity through the cap as well. Could C9 be the culprit causing all this chaos? Although when I test C9 on my resistance mode it does what Id expect it to do, climb down in value then suddent jump up then repeat. Also the top two lugs of the SPDT are beeping with ground

[GGBB]

EDIT: on going through the bleep test once more, I'm getting bleeps on both side of R10 with ground and on both sides of D5/D6 with ground. I'm also getting beep on BOTH the anode and cathode of C9 which is very strange, and contiunity through the cap as well. Could C9 be the culprit causing all this chaos? Although when I test C9 on my resistance mode it does what Id expect it to do, climb down in value then suddent jump up then repeat. Also the top two lugs of the SPDT are beeping with ground

C9 may or not not be a problem, but what you've checked doesn't suggest it is. The problem is that both anode and cathode of C9 have continuity with ground - that doesn't mean C9 is faulty - unless you actually removed C9 and measured it and found continuity across it. You cannot check a capacitor for continuity/short if both ends are connected to the same reference (ground).

Take things one step at a time. You found no audio past Q2 - fix that problem first. No point in checking and trying to fix things downstream until you verify everything is fine upstream.

I took a few readings and it seems im getting no audio past Q2/D1.

What I don't understand about this is that Q2 and D1 are not connected, and D1 is past Q2. So if you have no audio past Q2, D1 and other components past Q2 - downstream - should be expected to also not have audio and not considered problematic just yet.

Figure out why audio drops out after Q2. Before anything else.

[Yata]

EDIT: on going through the bleep test once more, I'm getting bleeps on both side of R10 with ground and on both sides of D5/D6 with ground. I'm also getting beep on BOTH the anode and cathode of C9 which is very strange, and contiunity through the cap as well. Could C9 be the culprit causing all this chaos? Although when I test C9 on my resistance mode it does what Id expect it to do, climb down in value then suddent jump up then repeat. Also the top two lugs of the SPDT are beeping with ground

C9 may or not not be a problem, but what you've checked doesn't suggest it is. The problem is that both anode and cathode of C9 have continuity with ground - that doesn't mean C9 is faulty - unless you actually removed C9 and measured it and found continuity across it. You cannot check a capacitor for continuity/short if both ends are connected to the same reference (ground).

Take things one step at a time. You found no audio past Q2 - fix that problem first. No point in checking and trying to fix things downstream until you verify everything is fine upstream.

I took a few readings and it seems im getting no audio past Q2/D1.

What I don't understand about this is that Q2 and D1 are not connected, and D1 is past Q2. So if you have no audio past Q2, D1 and other components past Q2 - downstream - should be expected to also not have audio and not considered problematic just yet.

Figure out why audio drops out after Q2. Before anything else.

Thanks again for the help.
I've went through it with an audio probe and I've posted the picture here (red line is my audio signal)
One thing I've noticed is that closing the 'octave' switch (just using a dpdt atm) gives me sound all the way through to  the middle pin of Q3 and the + leg of D2.
I'm still confused as to why my sound isn't getting past Q3 now though, all 4 trannies are the same and I've tried every tranny in every slot to rule out a defective one.

[EBK]

Out of curiosity, if you remove all 4 transistors, is your result the same?

Also, what kind of transistors are you using?

One more thing:  what are your DC voltages on each transistor pin?

[Yata]

Out of curiosity, if you remove all 4 transistors, is your result the same?

Also, what kind of transistors are you using?

One more thing:  what are your DC voltages on each transistor pin?

Nah, If I remove the transistor pins I can only hear a faint clean signal up till about Q2. With the trannies in I hear a heavily distortion/fuzz sound, also noticed Q2 has very very faint sound on the other two pins (distorted ofc)

The pin votlages havent changed from my earlier post

Q1-7.66
-2.21
-1.61

Q2-2.21
-0.74
-0.14

Q3
-
-0.58
-

Q4

I also included a picture earlier on this page of what pin is what on the PCB if that helps, the transistors are 2N3904

here is the schematic/instructions : http://pedalparts.co.uk/docs/UltimatumFuzz.pdf

[EBK]

 Hmm.... You should be measuring the voltages by placing your common (black) probe on your circuit ground and measuring each point with the red probe, i.e., the values should be positive numbers.. Edit: I'm thinking those must have been intended as bullets instead of minuses.

Also, where you have "-" but no number, is that what the meter is showing?

[Yata]

Hmm.... You should be measuring the voltages by placing your common (black) probe on your circuit ground and measuring each point with the red probe, i.e., the values should be positive numbers.. Edit: I'm thinking those must have been intended as bullets instead of minuses.

Also, where you have "-" but no number, is that what the meter is showing?

0 volts, sorry for hte confusion, I should have just used bullet points.

[GGBB]

The voltages on Q3 and the fact that sound drops after Q3 are consistent with each other (good) and suggest that something is shorting Q3 collector - and maybe emitter - to ground. Shorting the emitter to ground is a problem, but shouldn't cause loss of sound - actually the opposite - huge gain. But if the collector is shorted to ground, then emitter would show 0 volts even if not shorted to ground (I think - experts please correct me if I'm wrong). So the next problem to figure out is why Q3 collector is 0 volts. This could be a faulty component or a solder bridge (even a tiny one that isn't easy to spot). The immediate suspect component is R17 - measure the resistance across it with no power source connected. If it is zero, either the resistor is bad (shorted) or somewhere (probably nearby) there is a solder bridge connecting the R17-C9-Q3C junction to ground. EDIT: It's also possible that C9 is a problem - you noted before that both sides have continuity with ground - to be sure I would pull it and measure - if you find that R17 is fine.

I didn't notice if you posted pics of the solder side of your latest build - if not, now is a good time.

[Yata]

The voltages on Q3 and the fact that sound drops after Q3 are consistent with each other (good) and suggest that something is shorting Q3 collector - and maybe emitter - to ground. Shorting the emitter to ground is a problem, but shouldn't cause loss of sound - actually the opposite - huge gain. But if the collector is shorted to ground, then emitter would show 0 volts even if not shorted to ground (I think - experts please correct me if I'm wrong). So the next problem to figure out is why Q3 collector is 0 volts. This could be a faulty component or a solder bridge (even a tiny one that isn't easy to spot). The immediate suspect component is R17 - measure the resistance across it with no power source connected. If it is zero, either the resistor is bad (shorted) or somewhere (probably nearby) there is a solder bridge connecting the R17-C9-Q3C junction to ground. EDIT: It's also possible that C9 is a problem - you noted before that both sides have continuity with ground - to be sure I would pull it and measure - if you find that R17 is fine.

I didn't notice if you posted pics of the solder side of your latest build - if not, now is a good time.

I tested the resistance of R17 (not sure how to read the display on the MM) but at the 20K setting it was showing 4.46 which is the same as the similar value resistor R24.


here is the pictures of the solder side

https://imgur.com/a/el14A

I've not pulled C9 yet but I'll try this afternoon, it's quite hard to pull components from these fuzzdogs boards though without @#$%ing the solder pads. When I pulled a bunch of caps from my last board it destroyed it completely.

edit: pulled C9 and still getting continiuty with ground on both sides of the pads C9 was connected to. Alsoi when I pulled C9 and tested my top resistance mode on it, it started with a number and then just climbed higher untill it went higher than the MM can measure.