Solaris Fuzz

[rpark71]

Hi again - can I ask about the audio probe path? Should you get signal on either side of component or just one side, where you see the track of the pcb? I think the issue is on Q1 collector as that's first point on path that has no signal, but have tried re-soldering but still without signal from looper pedal. I get a signal on the base pin but not emitter or collector, and I see the collector goes to CX4, where there's also no signal. I have transistor sockets - could that be defunct - assume they can't be wrong way round?

I notice that when I put audio probe on Q1 collector pin the signal (amp) noise goes dead, like something is shorting out? Bit stuck on what to do next?

[Zerro]

Now controll R3 and FUZZ pot (1k) and that capacitor C2 (22uF) with it.

[rpark71]

Thanks Zerro - not sure what you mean control them, but with audio probe signal comes through on R3, but goes quiet (no amp hum) on Fuzz pot or on C2. Does this help?

[jimilee]

Two things, check the orientation of the transistor, the note says reverse for npn. Second, look at the back of the board for shorts to ground or solder bridges.

[Zerro]

Seems ok. Now measure DC value at collector of output tranzistor.

[rpark71]

Ok, will check again for solder bridges... I'm using PNP transistors, as needed as I used the IC part of the circuit - I didn't understand this wasn't required if using NPN.

DC value of Q2 transistor on the collector pin is 9.76v

[Zerro]

9,8 V seems to me too much. Q2 is not opened properly = Q1 is too closed. Or emitor of Q2 is hanging off, not connected properly with ground by that pot 1k. It is about feedback via those resistors and pots I asked before. And about resistor in collector of Q1. Measure voltage at Q1 collector.

BTW what is power supply value?

[rpark71]

Hi Zerro - thanks again for any help. Watched a video on voltages when things aren't working...and said to supply following to anyone trying to help!

DC jack lug 9.42v
9v pad on board 9.42v
IN/OUT pads on board and on footswtich lugs both read 0v (I suspect that's not right?)

IC chip:
Pin1 9.42v
Pin2 5.52v
Pin3 0v
Pin4 -3.38v
Pin5 -9.4v
Pin6 4.64v
Pin7 6.18v
Pin8 9.42v

Q1 transistor: E 0v  B -0.33v  C -1v
Q2 transistor: E -0.33v  B -1v  C -0.34v

thanks, Rich

[Zerro]

Hi, at first reading you find at collector Q2 on -9,7V. Now it is -0.34V? What changed?

[rpark71]

Ah, meant to add that yes I noticed the difference. Sorry - Human error is what's changed.

Originally I was placing red probe on DC positive lug and and black on the collector of Q2, which gets 9.76v. After watching video on voltages I put clip onto black probe and then connected other end of clip to ground on pedal (enclosure) and took measurements, which gave readings sent.

[Zerro]

Don't know video you saw, but power values are measured against ground. Minus pole (mostly black wire) of your multimeter put at ground, and red use for measuring. That's what gives proper infos. Try to do it this way and send values at transistors.

[rpark71]

Yep, black probe on ground lug of DC jack and red on transistor legs:

Q1 transistor: E 0v  B -0.33v  C -1v
Q2 transistor: E -0.33v  B -1v  C -0.34v

On the base of Q2, I do seem to get fluctuating readings - sometimes 0v, sometimes -1v. ??

[Zerro]

Circumstances around Q2 are bad. If at basis is only 1V, at collector cannot be so low power. Controll this element and collector resistors aiming up to power console.

[Bio77]

Are those trimmers meant to adjust the bias on the transistors?

[Zerro]

Only trimmer BIAS sets something similar. Other Pots are setting some sound charcteristics. But in this case is something wrong around Q1. At collector of Q2 must be something about -5V DC.