Continuing Issues with Fuzz Face Clone

[Slowpoke101]

OK....Interesting.

Remove power and set your multimeter to low ohm resistance test or continuity. Just make sure that when you short the probes together the meter displays zero (or close to it ) or beeps. Check out the following picture. Confirm that there is continuity between all the connections marked with a yellow dot. Also test to see if when one probe is connected to the DC connector's negative terminal that there is continuity to all the yellow dot connections. These tests must be done with your meter and not visually - something is hiding and I think it is a grounding issue.


Click on the image for a bigger version.

[SightsSetStudios]

I got continuity on all the ground points.

[Slowpoke101]

That is good. Now set your multimeter to voltage measurement and apply power to the pedal. Attach the negative probe to the black wire terminal of the DC connector and then measure the voltage on the red wire terminal of the DC connector - confirm that it is about +9V DC. If it is about +9V DC then leave the negative probe attached to the black wire terminal on the DC connector - this point I shall refer to as the 0 (zero ) volt connection.

Have a look at the following image and test that +9V DC (or close to it ) is present on the connections marked with the blue dots. Also confirm that 0 (zero ) volts is measured on the yellow dot connections.

[Slowpoke101]

And here is another silly question.

The image below is a close-up of the DC power connector. One of the black wires appears to be a bit odd. In as it doesn't seem to be connected. Is it?

[SightsSetStudios]

8.9v at the jack and all blue points. Zero at all yellow points.

The black wire in that picture looks disconnected because the wire melted through the other side a bit so that part is just insulation. It's connected though.

[Slowpoke101]

OK. All is good so far. Next task is measuring voltages again but at specific points labelled 1 to 9 in the following image. Again leave the negative probe attached to the black wire terminal on the DC connector - the 0 (zero ) volt connection.



Please note down the voltages that you measure and post them here. Also, point 9 should be the Cathode of the 1N4001 power diode. The Cathode is the end of the diode that is the "banded" end (silver paint ). Make certain that this is the case.

[SightsSetStudios]

Number nine is the non banded side. The banded side is on the ground pad.

1 - 0v
2 - 3.94v
3 - 4.52v
4 - 5.12v
5 - 4.52v
6 - .860v
7 - .868v
8 - 8.75v
9 - 8.9v

[Slowpoke101]

OK. Getting interesting.
Would you be able to upload a picture of your multimeter please. I need to see if can do a particular test which may help.
And one last VERY silly question - what brand of DC power pack are you using?

[SightsSetStudios]

It's a Neuma brand guitar pedal power supply off Amazon. Highest reviewed.

Mm https://imgur.com/gallery/CsImPqj

[Slowpoke101]

That is a very nice meter and the power supply seems pretty good too. Now your saga may be getting close to a positive conclusion. Please don't get too upset but.......You have the probes installed into the meter incorrectly. You are reading voltages with the reverse polarity. Check out the following image;



This is actually confirmed by your pedal power supply. It has a polarity image printed on it which shows as being Centre (tip ) Negative.



Now, what to do... Sort out the probes of course. Make certain that there is no power applied to the pedal and then swap over the red and black wires going to the DC power connector. Then re-install the 1N4001 power diode the other way around.

Apply power and see if this trying contraption will now work. Don't worry about damage to the transistors yet...Low voltage and low current incorrectly polarised usually doesn't harm them.....Usually..

[SightsSetStudios]

Oh man, that's hilarious. I'll report back and see what happens.

[SightsSetStudios]

Swapped the probes and swapped the hot and cold wires at the jack and flipped the diode. Now I'm not getting any passthrough when it's inactive and when it's active it sounds like it's working, just extremely quiet.

[Slowpoke101]

OK. Weird. I take it that you did have bypass working before and now you don't.....
Anyway, just for the moment we shall concentrate on the board. Can you re-measure the voltages again ? 1 to 9.
The readings will hopefully make more sense.

Some more questions. Do you have any other effects in series with this pedal? And are you (or were ) powering any other effects with this same power supply?

[SightsSetStudios]

Yep, bypass worked before.


1 - 0v
2 - .612v
3 - 1.02v
4 - 6.14v
5 - .644v
6 - 0v
7 - 0v
8 - 8.8
9 - 8.9v

[SightsSetStudios]

No other effects when resetting and the power supply is only supplying this pedal.

[Slowpoke101]

Loss of bypass signal is most likely due to a broken wire or a wire touching another wire unintentionally (foot-switch terminals are notorious for this ). Closely inspect your wiring and correct anything that may be questionable.

But first, your voltage measurements are very interesting. Q1 is not well and I am in serious doubt about Q2. The voltage measurements for points 3 and 5 should be the same as they are both on the same copper track. Remove power and measure the resistance of that track. Also could you measure the resistance between point 6 (Q2 emitter ) and the Zero Volt terminal on the DC power connector please.

[SightsSetStudios]

Don't see any wiring issues. Only thing I changed since it worked was swapping the wires going to the dc input. Voltage on 5 is the same as 3, done know why it didn't measure correctly the first time.

[SightsSetStudios]

Resistance between the negative input and point 6 is just above 2k ohms

[Slowpoke101]

OK. A resistance of 2K is odd but I will keep that in mind.

Do you have any spare BC108 (or similar ) transistors and a spare 22uF capacitor?
If you have those parts available please replace the ones currently on the circuit board and re-measure the voltages.

Another resistance test - remember that circuit must not be powered when measuring resistance. Please test the resistance between the DC connector 0 Volt terminal and the enclosure. It should be very close to zero.

Another silly test is to see if bypass signal can pass when the power supply is not connected to the pedal. This is not as silly a request as it seems. It's to do with grounds and unwanted grounds.