My univox super fuzz pedal kit won't work

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

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snow123

the reason i say "i dont think im getting 9v" is 'cause the number on the MM im using goes up by itself and sometimes stays arounds the 7-9mv area.

eh la bas ma

#101
Well, that might be the cause of your trouble. I forgot to say that the pedal needs to be connected to the battery or a 9V DC power supply and switched on, before you check the voltage on the pcb's 9V pad.

If you still don't have 9V, turn it off, unplugg all power sources, check the wiring on your DC power jack (sometimes the tip of the wires can touch each other and create a short). If it is correct, look for suspicious soldering joints that could need reflowing on your pcb ( remember transistors are heat-sensitive, you need to be quick if you apply heat around them).

Edit: if you're using a battery as power supply, test it with your MM to see if there is really 9V. The battery needs an audio jack plugged in the IN input to feed the circuit, that's why it's connected to the IN jack.

Edit 2 : On your picture I can't really see what is connected to the three DC power jack's terminals. It needs to be wired precisely as shown on the instructions.
"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

and i dont think any wires are shorting out on the dc jack 'cause i dont have the battery clip connected and i have a heatshrink on the lug that connects to the pcb, and i have tape covering up the pots.

eh la bas ma

This is simple : there is a red wire going fron the DC jack to the pcb 9V pad. A direct connection from your power supply to the board. If your MM can't read  9V on this pad, either you are using the wrong methode to take voltage measurements with the MM, or the wire isn't connected to the right power jack's terminal.

To read voltage you have to keep the black lead on ground first, and make a steady contact to the pcb 9V pad with the red lead. MM set on DC voltage as described in reply #88.

I think the circuit isn't properly fed with current, that's why it doesn't work yet.

"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

oh i think i was on AC instead of DC lol

snow123

i just set it to DC and im still getting nothing

eh la bas ma

#107
Was the pedal switched on with the status led activated, when you tested for 9V on the board ?
"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


eh la bas ma

#109
Did you check the DC power jack wiring to see if it is exactly connected as shown on the instructions (middle lug for the battery, outer lug for pcb 9V and square-angled lug for ground) ?

here is a clear exemple on page 4:

https://www.musikding.de/docs/basics/installationguideV001_en.pdf

An other possibility would be that the board isn't correctly connected to ground, preventing the current from coming in the pcb. On schematics, the pcb ground pad is only connected to the 3PDT footswitch. You can try to add a wire from the DC jack's ground to the board ground's pad (G).

Edit : sorry, I missed the Out jack that should already do the connection between the DC power jack GND and the pcb's GND. Just in case, you should check if every ground connections shown on the instructions is correctly wired in your build.
"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.

duck_arse

can you please tell us the make and model number of the multimeter you are using, and/or take a photo of the meter as you do a voltage measure, say of the +9V onboard connection?
I had a slight fever

snow123


snow123

i have another one that beeps but its cooked

antonis

#113
Black probe in COM (GND) and Red probe in place of Black one (VΩmA)..
(and voltage range selector on 20VDC)



P.S.
I'm not surprised for your cooked multimeter.. :icon_wink:
"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..

eh la bas ma

Quote from: antonis on April 28, 2021, 03:55:26 PM
Black probe in COM (GND) and Red probe in place of Black one (VΩmA)..
(and voltage range selector on 20VDC)





Now you should be able to test for 9V on the pcb, and give us some more accurate voltage readings on your transistors's legs ?
"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

#115
i got 9.2 volts now

snow123


Q1
C = 5.6
B = .7
E = .1

Q2
C= 9.2
B= 5.6
E= 5.1

Q3
C= switches between 6.1 & 6.2
B= 3.3
E= 3

Q4
C= 1.7
B= 1.8
E= 1.3

Q5
C=  1.7
B= 1.9
E= 1.3

Q6
C= 3.5
B= 1.1
E= .5

i had the DMM on 200 DCV btw

snow123

i also had the black lead on the 9v jacks GND

eh la bas ma

#118
According to the voltage chart on this file, looks like all your transistors are behaving correctly.

http://generalguitargadgets.com/pdf/ggg_superfuzz_instruct.pdf

This should mean that everything is in order on the pcb, at least until Q6 included.

Check your soldering on your IN/Out jacks, on R30, R31 and R32, also your soldering and orientation of  C16 and C17. There is a jumper between lug 2 and 3 on the Tone pot, check if it's ok, and see if there is no mistakes with the pot's values and wiring*.

If it's allright, it's very possible that you have made a mistake with the wiring somewhere, or with the way you plugged your guitar and your amp to the pedal. An other possibility would be a short on your footswitch (although I don't notice anything suspicious on your picture).

I'm sure you know this already but I'll say it nonetheless, just to make sure : your guitar's cable goes to In (J1) and the Out jack (J2) goes to the amplifier's cable.

I think you are very close to finish this build...

*Edit : in the wiring instructions, pots are viewed from the back, the way they are when you look inside the enclosure.

"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

I think something is still a little weird.  ??? Base voltages higher than collector? 

Q4
C= 1.7
B= 1.8
E= 1.3

Q5
C=  1.7
B= 1.9
E= 1.3