JL Audio 1000/1 Amp Distorted Output Troubleshooting Tip.
After repairing several open via's on a JL Audio 1000/1 input daughter board that originally the amp had a no output symptom, it now had distorted output. Even though I carefully looked at each via and double checked with a meter I figured maybe one was intermittent so I tapped on the board. The output went back and forth from normal to distorted.
Checking signals I found the pad of pin 1 of U2 had no signal. Upon closer examination I found that pin 1(1 output) on U2 was not touching the pad. I had repaired a open via under U2 and the front of the chip was raised ever so slightly keeping pin 1 off the pad. See picture. Looking straight down on it it looked connected but looking at it from a side angle it's readily obvious it's not connected.
Lesson learned: After replacing a surface mount chip look at from a side angle to double check solder connections not just straight down. I usually do this but not this time. It pays to be consistent.
Last edited by kds9591; 6th January 2013 at 03:59 AM.