Abyss LED stay lit

[adamgs82]

Hello,

I just finished by Abyss build and it works great, but when the rate knob is 100% CCW and Intensity is 100% CW, the led slowly stops pulsing until it stops completely and stays lit, causing no modulation.

If I tweak the knobs, it gets going again and works fine util the rate and intensity are set back to rate 0%, intensity 100%.

I've seen other posts about somewhat similar issues, and I've verified that my dual gang pot is not contacting anything, the electrolytic caps are the correct values and oriented properly as are the transistors. I took everything out of the box and double checked any incidental contact, and everything is clear.

I used a yellow LED from Tayda. Per their site, forward voltage is 2 - 2.3. Wondering if it could be the LED...

Any ideas on anything else that I should check? It's not a huge deal, but it just seems that it shouldn't work this way.

Thank you!

 

[adamgs82]

I've been playing around a bit more. If the intensity is at about 3/4 or more and the speed is around half, then the same thing happens. I've found a spot where the intensity is fairly high, and the speed at any range works fine.

I guess now I'm more curious than anything to see what may be the problem. I'm thinking the LED itself, but that's just a hunch... If the intensity is high and the speed low, that means there's little resistance at one stage and more on the other. Could this be something with the LFO?

I've not taken any readings on a chip or transistor... everything else seems to work fine, just looking for ideas.

Thanks again!

 

[Chuck D. Bones]

As this is your first time in this forum, I'm going to recommend that you read some of the other posts in this forum and be prepared to answer the following questions:
Have you cleaned the board to remove all of the flux residue?
Have you performed a thorough visual inspection of all solder joints?
Have you substituted any parts?
Can you post clear, detailed photos of both sides of the board?