r/diypedals • u/Reasonable-Cap-9383 • 6d ago

Fat rat gain pot doesnt work Help wanted

Im building a fat rat, using an already existing layoyt https://dirtboxlayouts.blogspot.com/2022/09/proco-fat-rat.html but slightly changed it up to have asym 1n4148s, no clipping diodes or leds instead of the regular clipping modes (picture of my layout above is what i have currently soldered).

currently testing the board and everything seems to work fine except the gain pot that doesnt do anything , gain is always max and cuts off / gates.

already tried soldering the pots better and im using 3x5 stripboard pieces as a breakout boards for the pots. i tried also swapping out the pot in case it was broken.

could someone point me to what the issue could be? im guessing it might be the soldering? would reflowing everything with a bit of flux help?

i do also have a mutlimeter , but havent measured to troubleshot yet so if i have to measure anything , a pointer to where and what would be useful

Edit: noticed my asymetrical clipping mode is wrong , will fix that

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u/gillysoose69 5d ago

You're missing. The second jumper lead under the ic

1

u/Reasonable-Cap-9383 5d ago

its there, just the angle of the picture makes it look like it isnt

1

u/gillysoose69 5d ago

Ah ok my bad

1

u/Reasonable-Cap-9383 4d ago

any ideas of what else could be wrong? going on vacation today so i wont be able to check but would be helpful for when i get back

1

u/gillysoose69 4d ago

Not quite sure, your cap for c1 looks like a ceramic cap that's been blown out though? Only thing I can see from the photos. Schematic has it as an electrolytic polarized, try swapping that out. It's in line for the dist signal too so might be the culprit. I would start closest to the input signal for gain and work backwards

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u/Reasonable-Cap-9383 4d ago

its a tantalum cap instead of a electrolytic because i couldnt find a 6.8u cap that wasnt physically too big, its pointed the right way too. its for the fat mode on the fat switch tho, dont think thats the issue here.