Post by wdln on Aug 16, 2020 20:17:03 GMT
My newly-working R-85 developed an intermittent short in the right channel yesterday. It seemed like it was one or both of the tone control boost switches (bass and treble) at fault, so I took the amp apart and hit them with some Deoxit. One switch was kinda stuck in place so I figured that was probably it. When I put it back together both channels were cutting out, and it didn't seem to matter where you touched it; the short would come and go by jostling anywhere on the amp or cabling. In other words, it was way worse.
Remembering this post, I pulled it apart again, cleaned all the connector pins on the preamp and amplifier boards, and re-soldered all the pin connections going into the boards. I think there may have been some cracked joints on the longest connector where the jumper wires are but I did all of the connectors just to be safe. And wouldn't ya know, now it works perfectly, and no amount of wiggling stuff makes either channel short out.
You wouldn't believe how much black crud came off just a couple dozen connector pins. So if you're having an issue, like Ron says, check the wiring first!
Remembering this post, I pulled it apart again, cleaned all the connector pins on the preamp and amplifier boards, and re-soldered all the pin connections going into the boards. I think there may have been some cracked joints on the longest connector where the jumper wires are but I did all of the connectors just to be safe. And wouldn't ya know, now it works perfectly, and no amount of wiggling stuff makes either channel short out.
You wouldn't believe how much black crud came off just a couple dozen connector pins. So if you're having an issue, like Ron says, check the wiring first!