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SOLVED UberFuzz - No LED ?

I built an UberFuzz using your PCB. Everything works (pots, toggle switch, I get the intended sounds when I turn it on, however, I have NO LED indicating that it's on. Nothing. I did use three part substitutions...

R3 calls for a 1.8K resistor. Not having any, I subbed a 2K resistor. This is the Emitter resistor for Q1, I imagine there is little if ANY affect from this.

Next, R9 calls for a 150K resistor. I do not have any of that value either - the closest I have is 220K, so I subbed that, and because I did, I increased the value for R11 to 300K (a 220K is called for in the build instructions). My rationale is that these are setting the DC voltage for the base of Q3, and the ratio between the 300K / 220K combination is not too far off from a 220K/150K combination. Since the transistors seem to be working, I doubt this is hindering lighting the power LED.

Finally I used BAT41 clipping diodes (D1 and D2) instead of the OA90s that are called for. The clipping sounds correct, and the effect works, again, doubtful this is causing the LED light to not work.

I checked for solder bridges, found none but scraped a few spots anyway. No luck.
I checked for 9VDC coming into the hot side of the LED, it's there.
I replaced the LED with a new one. VERIFIED that the long lead is in the square pad. Also heat-shrinked the hot lead. No luck.
Verified that R100, D100, and C100 are all the correct Values.
Replaced the 3PDT switch and triple checked that it is wired according to the diagram provided in the instructions. No luck.

Build docs, including schematic are attached. Pics of mostly completed and complete board are posted below.


image3.jpegimage2 copy.jpg



Staff member
The Anode (long lead) goes into the round pad (marked A on the PCB).

Sounds great, and FYI, those substitutions didn't seem to impact the tone whatsoever. In fact, it's probably just a shade smoother sounding than the original. Not sure if that's the substitutions or the PedalPCB design of this clone?


Staff member
Why in the world was I convinced it was the other way around??? That fixed the issue. Thanks so much!!
There is a lot of confusion about LED pinouts. I decided to adopt the same standard used for all diodes, and mark the Anode (A) and Cathode (K) on the PCB whenever possible.
makes sense now. The off board drawing shows the long lead closer to the Square Pad... that's why I was thinking it was right. But knowing the 'A' vs 'K' now, I'll not be making that mistake! Thanks again!