My univox super fuzz pedal kit won't work

Started by snow123, March 09, 2021, 04:57:33 PM

Previous topic - Next topic

snow123

Quote from: Rob Strand 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.
yea i have a desoldering pump and have been using it

snow123


andy-h-h

You will most likely need a multimeter to get this sorted out.   A DIY audio probe will also be handy, and you probably already have the parts to make one.   You can easily follow the signal path on a super fuzz.

First build?

snow123

wait does it matter which way a resistor goes? cause on my multimeter im getting different readings depending where i have the probes

snow123

Quote from: snow123 on March 12, 2021, 03:46:23 PM
wait does it matter which way a resistor goes? cause on my multimeter im getting different readings depending where i have the probes
yea its my first full pedal build

snow123

Quote from: snow123 on March 12, 2021, 03:46:23 PM
wait does it matter which way a resistor goes? cause on my multimeter im getting different readings depending where i have the probes
i used the multimeter on mostly everything and im getting readings on the wires on the pcb, in/output jacks, dc in, and footswitch but im mixed results everywhere else on the pcb.

snow123

And it's impossible to check the pots since this is how I have everything set up


eh la bas ma

#27
You'll have unstable readings on resistors if you are moving the probes along the legs.  If you are steady, it shouldn't do that.

You should test your capacitors to see if they are still ok, since Andy had doubts : he may be right.
Potentiometers are built like tanks, you shouldn't worry about them being broken. Their values is the most important thing, and their wiring : you see their back on the schematic.
Did you correct the soldering ? There was still some suspicious pads on your last pic.
"One Cannot derogate, by particular conventions, from the Laws which relate to public Order and good Morals." Article 6 of the Civil Code.
"We must not confuse what we are and what society has made of us." Theodor W. Adorno.

snow123


snow123


eh la bas ma

#30

Green : possible short, need cleaning.
Blue : is it empty ?

Red : the solder is not on the entire pad = bad connection, just touch the pad with the iron untill the solder melt again (2 or 3 sec) and it should be better.
     
Edit : Maybe your iron isn't hot enough, it should be set around 390-400°C
Did you correct all polarized caps 's orientation ?
"One Cannot derogate, by particular conventions, from the Laws which relate to public Order and good Morals." Article 6 of the Civil Code.
"We must not confuse what we are and what society has made of us." Theodor W. Adorno.

snow123

blue is empty and yea i corrected all of the electrolytic caps

eh la bas ma

#32
One more thing : It's ok if the ground poles of your input/output jacks are in contact with the enclosure. It's a problem if the Tip sides of the jacks touch anything, I mean the part where you 've soldered IN/Out wires and the parts that's in contact with the guitar/amp 's jacks. both shouldn't touch anything inside the enclosure (except maybe isolated wires around them, or isolated pots).
Edit: you can carefully bend the soldered poles a little with pliers if needed. Caution, jacks's plastic parts can break if you are going too fast .
"One Cannot derogate, by particular conventions, from the Laws which relate to public Order and good Morals." Article 6 of the Civil Code.
"We must not confuse what we are and what society has made of us." Theodor W. Adorno.

andy-h-h

#33
Quote from: eh là bas ma on March 12, 2021, 05:12:24 PM
You'll have unstable readings on resistors if you are moving the probes along the legs.  If you are steady, it shouldn't do that.

You should test your capacitors to see if they are still ok, since Andy had doubts : he may be right.
Potentiometers are built like tanks, you shouldn't worry about them being broken. Their values is the most important thing, and their wiring : you see their back on the schematic.
Did you correct the soldering ? There was still some suspicious pads on your last pic.

The ones in the signal chain should be fine, the only one that could be damaged is the filter cap across the power supply (C17, 47uf).  Resistors are nearly indestructible, as are pots and standard caps.  Transistors can be cooked with too much heat.

The board is looking much cleaner by the way.  Nice..   ;)

If you can, pull the entire circuit out of the box to check it.  I often use a piece of cardboard with holes in it to hold the pots and switches while I work, before I box it up.  Sometimes I even label the cardboard to help avoid stupid mistakes.  Much easier than working in the box - use the holes on the box as a template.   

If your multimeter has a continuity tester, move through the wiring check that nothing is shorted / not connected where it should be.  i.e. output jacks and switches.   If it works on the bench and not in the box, then you probably have a short to the box.   



   

snow123

#34
Ik it's been a bit as I took a break from the project but I just desoldered a bit of where one of the trimpots is and will it be ok??


antonis

"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

iainpunk

2 remarks about the picture:
- the picture isnt focussed right, the parts we don't care about are sharp, while the thing we want to see is a blur
- get an old toothbrush, some cleaning alcohol and q-tips to clean off as much of the brown gunk from that board as you can, so we can see whats going on underneath the gunk

i suggest you lookt at this link:debugging guide

cheers
friendly reminder: all holes are positive and have negative weight, despite not being there.

cheers

snow123


snow123


iainpunk

Quote from: snow123 on March 20, 2021, 10:04:48 PM
i hope thats better
yes, great!

i think it would be wise to add a snipped component lead and use that to make a connection across the burned pin and the next pin over, so there actually is a current path, i doubt the burned track conducts much.

cheers

edit: if it still doesn't work, i re-suggest you look at this link:debugging guide
friendly reminder: all holes are positive and have negative weight, despite not being there.

cheers