Jamie Starr
Active Member
Hey guys, I though I would pass on cold solder joint experience I just had on my 2275. I restored this 2275 about a year ago. Because of some distortion issues in the left amp, I essentially rebuild both amp boards by replacing nearly all caps and transistors. The restoration came out great and I have been using the 2275 ever since. I thought it was built like a tank and did not expect to open the cover during my lifetime.
Last week the right channel stopped working. I only heard a buzz. It sounded like a wire had come off somewhere or something was grounding out. I had a hard time thinking what may have gone bad since the boards were basically rebuilt.
Checked the pre-in/main outs and it was definitely the amp board. No broken wire. Tested the output transistors, and they were fine. Tried freeze spray with inconsistent results. Audio would come back in like 10 seconds after spraying, so I wasn't sure what has happening.
Long story short I started tapping around the board and when I would hit a resistor, the relay would turn on and off. I figured a bad resistor. Pull out and tested fine. Re-installed and re-flowed. Bingo, problem solved. I re-flowed the rest of the resistors and any other joints that looked suspect.
I never tend to think of cold solder joints or a bad resistor when troubleshooting. I won't make that mistake again.
Last week the right channel stopped working. I only heard a buzz. It sounded like a wire had come off somewhere or something was grounding out. I had a hard time thinking what may have gone bad since the boards were basically rebuilt.
Checked the pre-in/main outs and it was definitely the amp board. No broken wire. Tested the output transistors, and they were fine. Tried freeze spray with inconsistent results. Audio would come back in like 10 seconds after spraying, so I wasn't sure what has happening.
Long story short I started tapping around the board and when I would hit a resistor, the relay would turn on and off. I figured a bad resistor. Pull out and tested fine. Re-installed and re-flowed. Bingo, problem solved. I re-flowed the rest of the resistors and any other joints that looked suspect.
I never tend to think of cold solder joints or a bad resistor when troubleshooting. I won't make that mistake again.