Author Topic: My univox super fuzz pedal kit won't work  (Read 8120 times)

snow123

My univox super fuzz pedal kit won't work
« on: March 09, 2021, 04:57:33 PM »
I bought a super fuzz kit from general guitar gadgets and I think I did everything correctly but when I put a battery in the led wont turn on and the pedal just works as a mute switch. Heres the layout I followed: http://generalguitargadgets.com/pdf/ggg_superfuzz_lo_mods.pdf
And here's my work:


snow123

Re: My univox super fuzz pedal kit won't work
« Reply #1 on: March 09, 2021, 04:59:38 PM »
FIY i did change the footswitch and led 'cause i thought they might have been faulty or something.

eh la bas ma

Re: My univox super fuzz pedal kit won't work
« Reply #2 on: March 10, 2021, 11:16:51 AM »
Hello,

I'd suggest to post a pic of the circuit's soldering side, and an other with the wiring clearly distinguishable and well arranged, so that we can check if everything is in order. Unfortunatly, your picture is out of focus.

Usually when the led doesn't light up in my builds, the led polarity is wrong or there is a mistake in the footswitch's wiring, or there is no power coming to the led's anode. You can check the led with a 9V battery and a 4.7k resistor placed between positive sides of both battery and led.
 Is there any sound in bypass mode ? If not, one or both jacks 's wiring may be wrong, or it's the footswitch's wiring again, or there is a short somewhere. It could also be possible that you plugged in the wrong cable to the In/Out jacks when you did the test. This often happens to me !

Be that as it may, a multimeter set on continuity mode will allow you to rule off every possibilities I wrote above.

 Here is a classic Footswitch's wiring exemple :
 


Edit: I noticed you have some germanium diodes on this build : Sometime the marking (I've been told it's the russian way) is  on the positive side instead of negative, as shown on the layout. You might want to check that too with your multimeter set on "diode mode" (like the led symbol).
« Last Edit: March 10, 2021, 01:24:11 PM by eh là bas ma »
"unity-gain non-inverting stage", "ground leg","post-pick moments", I love this colorful forum.

snow123

Re: My univox super fuzz pedal kit won't work
« Reply #3 on: March 10, 2021, 03:18:57 PM »
yes, there is sound in bypass

snow123

Re: My univox super fuzz pedal kit won't work
« Reply #4 on: March 10, 2021, 03:27:48 PM »
Also heres some better pics of the inside












andy-h-h

Re: My univox super fuzz pedal kit won't work
« Reply #5 on: March 10, 2021, 04:04:26 PM »
There’s a pretty decent chance that you have a number of solder bridges across the board.  Some connections look like they don’t have enough solder, some too much.  Test continuity with a multimeter if you have one.  If you don’t have a meter to check, reflow you soldering if it looks close to another pad - works better with flux and a hot iron.  Do you have anything to practise on?  A few test runs before you hit the board might be needed. 
« Last Edit: March 10, 2021, 04:10:02 PM by andy-h-h »

eh la bas ma

Re: My univox super fuzz pedal kit won't work
« Reply #6 on: March 10, 2021, 04:48:26 PM »
I agree with Andy.

The soldering side really needs to be cleaned. I would pass the iron between almost every solder joints to clean the spaces between them. Better to do some quick moves to avoid overheating the pcb (no more than 2 or 3 seconds, even less if you can, and sometimes let the pcb cool down several seconds before coming back with your iron).
 You should move the iron even more quickly around transistors because they are very heat-sensitive. If the pcb gets blackened by the heat, your iron is too hot.

 After that you can softly use an old and clean toothbrush on the soldering side, to gently give a final cleaning touch.

Some wires seem to be quite burned. If you have no change once you cleaned the pcb, next step should be replacing those with fresh ones. Jacks wiring seems ok, but wires are sligtly burnt too, that would make me uncomfortable, or even suspicious   :).

Are you sure the germanium diodes's orientation is correct ? I had some trouble in the past with these and their unusual markings.

Finally, something should be used to prevent the pots from shorting the soldering side of the pcb, once everything is in the enclosure. Plastic tape is ok : just put some tape at the back of the pots located near the pcb : Nothing can touch your pots, not even an other pot.
« Last Edit: March 10, 2021, 05:00:54 PM by eh là bas ma »
"unity-gain non-inverting stage", "ground leg","post-pick moments", I love this colorful forum.

snow123

Re: My univox super fuzz pedal kit won't work
« Reply #7 on: March 10, 2021, 04:53:48 PM »
should i worry about any wires sticking out a little bit from the pcb or anything?

eh la bas ma

Re: My univox super fuzz pedal kit won't work
« Reply #8 on: March 10, 2021, 05:06:25 PM »
Use cutting pliers to remove carefully anything that sticks out too much from the soldering side of the pcb. This can put some dirt on the circuit, hence the toothbrush. From what I can see, you are ok though.
« Last Edit: March 10, 2021, 05:35:53 PM by eh là bas ma »
"unity-gain non-inverting stage", "ground leg","post-pick moments", I love this colorful forum.

snow123

Re: My univox super fuzz pedal kit won't work
« Reply #9 on: March 10, 2021, 05:29:02 PM »
ok, thx

snow123

Re: My univox super fuzz pedal kit won't work
« Reply #10 on: March 10, 2021, 06:42:10 PM »
Is this better? The reason I have a bunch of solder near one of the trimpota is 'cause one of the pads are ekinda burnt out so it's a pain to do anything there.




snow123

Re: My univox super fuzz pedal kit won't work
« Reply #11 on: March 10, 2021, 06:42:43 PM »
i also had to change out the germanium diodes for other ones since i lost em lol

snow123

Re: My univox super fuzz pedal kit won't work
« Reply #12 on: March 10, 2021, 07:49:55 PM »
And I just realized that the pedal doesn't even need power to do anything, like I can just have it there without any power, and with my guitar going into the out (or input it doesn't matter) and when I try to turn on the pedal it just mutes everything

andy-h-h

Re: My univox super fuzz pedal kit won't work
« Reply #13 on: March 10, 2021, 08:03:18 PM »
That's normal for a true bypass pedal - it should pass signal without power. 

Either Q4 or Q5 is orientated the wrong way around - probably Q5.  They should be facing the same direction, also check Q6. 

Polarity of pretty much all electrolytic caps looks to be wrong too - the stripe is the negative side.
« Last Edit: March 10, 2021, 08:09:37 PM by andy-h-h »

snow123

Re: My univox super fuzz pedal kit won't work
« Reply #14 on: March 10, 2021, 08:14:43 PM »
@#$%. i had no clue about the polarity and stuff

eh la bas ma

Re: My univox super fuzz pedal kit won't work
« Reply #15 on: March 10, 2021, 08:55:36 PM »
Germanium diodes give a special sound to your pedal, a more natural and dynamic character. You might want to find or replace them to get the best sound out of this circuit. Be carefull they have a glass body and can easily break if you bend the legs too close to the glass.

It's much better but it looks like you still have some suspicious soldering joints : you can use the picture you posted and zoom in to spot the few remaining suspicious pads. 3 of them obviously need a bit more solder.

 The trick is to touch the pad with the tip of your iron, then put the tip of the solder wire on the pad too,give it the right amount of solder (not too much) and finally move the iron away touching and following the component's leg all the way up, to make a nice geometric cone. And do it quickly so that the pcb doesn't get overheated. It's easy once you are used to do it.
If two legs are too close of each other, apply some heat and use a screwdriver or the tip of the iron to bend the legs toward the opposite side.

Flat side of transistors should match the flat line on the pcb's layout.
« Last Edit: March 10, 2021, 10:43:09 PM by eh là bas ma »
"unity-gain non-inverting stage", "ground leg","post-pick moments", I love this colorful forum.

andy-h-h

Re: My univox super fuzz pedal kit won't work
« Reply #16 on: March 10, 2021, 09:11:40 PM »
@#$%. i had no clue about the polarity and stuff

I hate to say this, but about now is when you might want to consider starting fresh.   :-\

Just on polarity, C17 is across V+ and ground.  Electrolytic capacitors explode when they are the wrong way around across power rails (a small pop).  The ones in the signal path will not explode, but it's not good either. 

The diodes are the least of your worries at this point in time - they really don't do much in this circuit anyway.  I've built a few, and the action mostly happens with Q4 & Q5.

eh la bas ma

Re: My univox super fuzz pedal kit won't work
« Reply #17 on: March 10, 2021, 09:25:03 PM »
@#$%. i had no clue about the polarity and stuff

I hate to say this, but about now is when you might want to consider starting fresh.   :-\

Just on polarity, C17 is across V+ and ground.  Electrolytic capacitors explode when they are the wrong way around across power rails (a small pop).  The ones in the signal path will not explode, but it's not good either. 

The diodes are the least of your worries at this point in time - they really don't do much in this circuit anyway.  I've built a few, and the action mostly happens with Q4 & Q5.

...but no capacitor have exploded yet, isn't it ? Otherwise it would be noticeable on the pic. I think it's still very much ok... The trimpot's burnt pad is a concern but it "could" be allright, this pcb seems to be good quality.
Edit: even if some caps are damaged (which I don't think they are ) It is easier and cheaper to find new ones and replace them than throwing all of it away, if I may say so.

There should be a swelling at the top of your capacitors if it's blown : here is 3 blown exemples


 Is it the case ?
« Last Edit: March 10, 2021, 10:02:29 PM by eh là bas ma »
"unity-gain non-inverting stage", "ground leg","post-pick moments", I love this colorful forum.

eh la bas ma

Re: My univox super fuzz pedal kit won't work
« Reply #18 on: March 10, 2021, 09:28:24 PM »
Do you have a multimeter and a desoldering pump?
"unity-gain non-inverting stage", "ground leg","post-pick moments", I love this colorful forum.

Rob Strand

Re: My univox super fuzz pedal kit won't work
« Reply #19 on: March 10, 2021, 10:20:19 PM »
If you have a multimeter measuring some voltages would remove a lot of guessing and allow people to zoom-in on the problem areas.
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