telehumbucker
Well-known member
My 70's mic pre is having some issues. It's the same pre (from vintage Midas board) that was discussed in the linked thread below. I had a tech look at it and in the process of trouble shooting he re-soldered some joints, during which, I think two of the joints were bridged. The posted picts show a working channel and the one with what looks like bridged joints.
Before the soldering was done, the mic pre input -both mic and line - was not functioning. The pre would power on but not receive any signal through the mic or line input.. After the soldering, I found that a wire had broken and was hanging loose on the input module. Had that resoldered and thought that would solve the input problem. But, instead, what happened was when the module was powered up, it melted one of the op-amps and shut off one of the power rails.
When I removed the module the power supply returned to normal functioning....but couldn't power up the problem
module without melting an op-amp and shutting down the power. So I visually inspected the solder job and it looks like in two places the solder joints are bridged. Any opinions on the situation welcome.
https://groupdiy.com/threads/vintage-70s-midas-channel-strip-problem-pro5a.85650/page-3
Before the soldering was done, the mic pre input -both mic and line - was not functioning. The pre would power on but not receive any signal through the mic or line input.. After the soldering, I found that a wire had broken and was hanging loose on the input module. Had that resoldered and thought that would solve the input problem. But, instead, what happened was when the module was powered up, it melted one of the op-amps and shut off one of the power rails.
When I removed the module the power supply returned to normal functioning....but couldn't power up the problem
module without melting an op-amp and shutting down the power. So I visually inspected the solder job and it looks like in two places the solder joints are bridged. Any opinions on the situation welcome.
https://groupdiy.com/threads/vintage-70s-midas-channel-strip-problem-pro5a.85650/page-3