Lemon Rockerverb- no sound when engaged

megatrav

Active member
I've been working on this build from guitar pcb mania.
I have bypassed sound. No sound when engaged but I do have an LED.
I took some shots of the board and I can't spot any bad connections so I think I might have the switch Ground and Control backwards. The PCB only says CNTRL.
I haven't tried swapping them yet but I wanted to post here to see if anyone might catch something else I may have done wrong.
D8E1A375-3995-4E14-B3DE-0B7D22196D96.jpeg 1356B69E-4BEF-4727-9D34-25382E24CF51.jpeg CF32E9F3-AD5D-4D76-9638-E0652C9C6873.jpeg 7C420E8D-B9B7-4F23-987C-2DAC7BFF7725.jpeg
Thanks!
 

megatrav

Active member
One other thing, is was able to bias the jfets and they're all sitting right around 4.5v. So signal is getting to them at least
 

carlinb17

Well-known member
what are the 0/1 and 1/1 eyes for? they appear to be referenced in the schematic however there is nothing in documentations for them.
 

megatrav

Active member
Drain voltage is one thing, signal is another thing. You can have perfectly biased transistors and no sound at all.
Trace the signal with an audio probe.
I really need to get around to making one of those. I was hoping someone would reveal something silly and obvious that I missed.
 

BuddytheReow

Breadboard Baker
An audio pot is stupid simple to make if you've got alligator clips.
This is what it would look like. Drew it real quick with TinyCAD
1630335335203.png



The jack you use doesn't really matter as long as you can solder 2 wires to it: ground and the actual signal (marked tip). That goes to a capacitor. The capacitor should be roughly 100n and I used a box film one. It's purpose is to filter our all unwanted DC in the signal (you guitar sends AC signal). The other unused lead of the capacitor is your audio probe or you can solder a wire to that to make it a bit easier for testing.
 

megatrav

Active member
it would be a good idea to put something on the two bare pot shells that are mounted above the PCB.
Yes, I had some sticky pads on the bottom. I removed them so that I could take pictures of the under side of the board
 

megatrav

Active member
An audio pot is stupid simple to make if you've got alligator clips.
This is what it would look like. Drew it real quick with TinyCAD
1630335335203.png



The jack you use doesn't really matter as long as you can solder 2 wires to it: ground and the actual signal (marked tip). That goes to a capacitor. The capacitor should be roughly 100n and I used a box film one. It's purpose is to filter our all unwanted DC in the signal (you guitar sends AC signal). The other unused lead of the capacitor is your audio probe or you can solder a wire to that to make it a bit easier for testing.
Thanks for the tip. Right now I don't have any gator clips or spare parts to make a probe, but that will be something I do in the future.
 

megatrav

Active member
Guitarpcbmania replied and said the 0/1 and 1/1 pads were originally added for modding, but they're useless and should be ignored.
I am going to try touching up all my joints and maybe swap the CTRL and Ground wires just to see if maybe it was something silly like that
 

Feral Feline

Well-known member
C10 is backwards.

I'd also recommend trimming the teats more and then reflow the solder — check for micro solder bridges, a lot of your pads look as though on the verge of being bridged either by solder or by leaning towers of teats.


I need to build mine up, but then the same could be said for a lot of PCBs I have...
 

megatrav

Active member
C10 is backwards.

I'd also recommend trimming the teats more and then reflow the solder — check for micro solder bridges, a lot of your pads look as though on the verge of being bridged either by solder or by leaning towers of teats.


I need to build mine up, but then the same could be said for a lot of PCBs I have...
Big thanks on C10. Since I uploaded the photo, I did reflow myself solder and check for any bridges. I will recheck and swap c10. Thanks for the assist!
 

Feral Feline

Well-known member
Flipped c10 and went over any long leads and checked for solder bridges.
No luck.
I've got the old build doc, which showed C10 oriented with + north; but...
according to the build doc you linked to, you had C10 the correct way round in the first place — sorry to have misinformed you.

Can you repost new pics after touching up the solder?
 

megatrav

Active member
I've got the old build doc, which showed C10 oriented with + north; but...
according to the build doc you linked to, you had C10 the correct way round in the first place — sorry to have misinformed you.

Can you repost new pics after touching up the solder?
No worries. I removed the cap and put it back in and later realized it was in the correct way all along haha.

I did try to clean up my ends. I do need to scrub the board as it's gotten a little messy from touching up the pads. Here are some pics I just took.

97702A00-10AF-4142-86E2-3D513A5B4C9C.jpeg FBCF665A-BB02-4379-B49D-BE15A6BB0063.jpeg 55D8DF58-BC5D-420D-9405-19070E766201.jpeg 70743E46-8E2A-44AB-8CB0-8A45BBFF35D0.jpeg
 

carlinb17

Well-known member
if you have an old guitar cable, a little bit of hookup wire and a .1 uf capacitor somewhere I would recommend making an audio probe.
 
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