Rack Compressor LED Bar Display Troubleshooting

MitchMev

Member
2015-12-06 7:03 pm
Hey everyone, a coworker recently got his hands on a 90's rack compressor from Rocktron (the 300G in case you're wondering) and asked me to fix a few things. One of the LEDs on the gain reduction display was not lighting and the whole level meter display stays lit no matter what.

I saw a bunch of bad solder joints on the LEDs so I touched those up and now the gain reduction display works properly. However, the level meter display is giving me some more trouble.

He mentioned the knob that controls the "0 level" for the LED display doesn't do anything and that maybe it was dusty or worn out. Well, the pot works properly, but the solder joints are pretty gnarly. It appears that someone tried to go in and do a mod/repair and destroyed the solder pads. Taking a measurement at the points where the traces connect to the next components I'm getting a reading of multiple megohms, so I'm assuming the pot is an open circuit (it measures at around 22k from its own leads)

I'm not certain that this is the main or only issue, but I'm pretty sure I need to fix that first. However, I'm not too experienced with rework and repair, so I'm wondering, is there an easy way to get solder to flow and connect the leads when there is little or no solder pad left?

EDIT: In case anyone is wondering, I generally followed this method, exposing some copper from the PCB trace and using a wire to connect the leads to the trace. I skipped the acetone and hot glue steps but I think it is solid enough: https://www.youtube.com/watch?v=cTnVg6Pmf-U
 
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