Lemon Rockerverb- no sound when engaged

megatrav

megatrav

Well-known 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!
 
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temol said:
Now it's reading the leaves... you should test the board with the audio probe before you make any further changes .. just leave the board as is.
Click to expand...
I finally had a chance to do some testing today.
Tracing the signal path, I get audio from In, C1 and R1.. here is where things get interesting.
I get audio when I touch the prove to the Gate of the actual transistor but not the Source or Drain legs.
However, just out of curious I put the leg of the probe where the holes for the through hole transistors go and I get audio at the spot where the Source leg would go but not the other 2.
Anyway, I am open to any suggestions
 
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Problem - signal does not pass through multiple points of connection.
Action - inspect connection points.

You have a: pcb trace, solder joint, transistor legs, transistor itself.
It's a fairly simple set.

My first thought - connectivity issue. Damaged trace, damaged solder pad, bad solder joint, short. And then maybe I'd check transistor.. it's not easy to fry a transistor (in my opinion) but it's of course possible.
 
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temol said:
Problem - signal does not pass through multiple points of connection.
Action - inspect connection points.

You have a: pcb trace, solder joint, transistor legs, transistor itself.
It's a fairly simple set.

My first thought - connectivity issue. Damaged trace, damaged solder pad, bad solder joint, short. And then maybe I'd check transistor.. it's not easy to fry a transistor (in my opinion) but it's of course possible.
Click to expand...
I think I can rule out the transistor since I am using a different one than I was using before but I will continue to investigate the issue. thank you for the responses
 
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megatrav said:
I finally had a chance to do some testing today.
Tracing the signal path, I get audio from In, C1 and R1.. here is where things get interesting.
I get audio when I touch the prove to the Gate of the actual transistor but not the Source or Drain legs.
However, just out of curious I put the leg of the probe where the holes for the through hole transistors go and I get audio at the spot where the Source leg would go but not the other 2.
Anyway, I am open to any suggestions
Click to expand...
Which Transistor are you referring to, Q1????
 
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If I may suggest - try to minimize soldering at this point. Now, with every soldering action you risk damage to the board. Take some isopropyl alcohol and clean flux residue. There's some burnt gunk around the pads and this does not help you and us to spot potential issues.
 
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temol said:
If I may suggest - try to minimize soldering at this point. Now, with every soldering action you risk damage to the board. Take some isopropyl alcohol and clean flux residue. There's some burnt gunk around the pads and this does not help you and us to spot potential issues.
Click to expand...
that is solid advice as well. I have been cleaning with alcohol after each time I do solder.
I am not very hopeful about this project working out, so I am going to see what I am able to do to get it working.
 
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Just wanted to do a quick update. I reached out to GuitarPCBMania via Facebook.
After a few questions, he recommended to try connecting a 1 Meg resistor from the transistor to ground like this:
15F1B310-2DC1-4241-BD96-20F03E907B16.jpeg 6D4DDF78-0AFA-4201-923D-963FE913AFC9.jpeg

So I am going to give that a shot and see if there is any difference
 
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I installed the 1meg resistor per his instructions and sadly it made no difference.
Using an audio probe I get signal from the in>C1>R1>Q1 gate. I do not get audio from the Source or Drain from Q1.
The signal does go beyond that to C4. However, the quality begins to sound choppy, distorted, and degraded. Not clear at all.
I am able to keep getting signal until I get to Q2, including the preamp pot, however the audio is still degraded.
It stops once I get to Q2.
So, either the issue starts at C4 or Q2?
 
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I will do some more testing tonight. I wish there was an easy way to record what I am heading, but I am doing testing through headphones since that is what I have to work with
 
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