BYOC 5 knob compressor SQUEAL HELP!!

I just put together my first peddal, a 5 knob compressor and I'm having some trouble. When I try to set the trim pot and I turn up the level past 9 o'clock it works for a few minutes then starts to squeal until I turn the level down and will work some more and do the same thing. I was very careful in making sure all the values were right in the components...even triple checking them. I did notice that two of the pots seem like they have rough spots in them when you turn them but chalked it up to alpha pots. I have modded several pedals recently with great results as well as wiring my tele's and am fairly handy with a soldering iron but not a pro at it. Any help would be greatly appreciated!!!!

i forgot to state that the only thing I changed was the red led to a purple one...don't know if it would matter but just in case. Again, I would really appreciate any help in this!
Les

I just looked over the board step by step and found a diode that the instructions show polarity one way but the board layout is printed the opposite... Will this cause a squealing sound from this?? Everything else is correct , I may just replace the diode and reverse it to see what happens.

You should really post this over at the BYOC forum. They will help quickly. You'll need good photos before you get any answers though. :cool:

I tried to get there but the site is down , so I was hoping someone had a similar problem.

Here's some pics if that helps