Wayniac
Active Member
I bought this amplifier new back in the 1980s. I knew it was a time bomb, but I continued to use it as as my second string backup amplifier for use when my main amplifier quit.
Fortunately, without fire or smoke, it clicked into protection one day and that was that. I swapped in my third string amplifier (M-50), and took the M-80 into the shop.
When I lifted the M-80, one of the binding posts fell off onto the table. Great. Luckily, I had a set laying around for a Pass F5 I'm building.
I tore it down and found one of the (6) 330 ohm resistors had succumbed to the corrosive capacitor glue. I hope this is the only problem.
I've ordered a full complement of electrolytics (except the main PS filters) including those on the display PCB. I also ordered new pots, a few resistors and zener diodes also corroded by the glue.
The glue has been removed. Much to my relief, the heat sink transistors all checked good.
I addressed the binding posts by fabricating a small panel from a scrap piece of 1/8" aluminum. I drilled and tapped the mounting holes to accept a 6-32 screw.
I removed and cut down the original bus bars, then soldered them to the new binding posts.
Tomorrow, I plan to replace the cheesy 20 AWG power cord and also replace the heat sink compound.
Fortunately, without fire or smoke, it clicked into protection one day and that was that. I swapped in my third string amplifier (M-50), and took the M-80 into the shop.
When I lifted the M-80, one of the binding posts fell off onto the table. Great. Luckily, I had a set laying around for a Pass F5 I'm building.
I tore it down and found one of the (6) 330 ohm resistors had succumbed to the corrosive capacitor glue. I hope this is the only problem.
I've ordered a full complement of electrolytics (except the main PS filters) including those on the display PCB. I also ordered new pots, a few resistors and zener diodes also corroded by the glue.
The glue has been removed. Much to my relief, the heat sink transistors all checked good.
I addressed the binding posts by fabricating a small panel from a scrap piece of 1/8" aluminum. I drilled and tapped the mounting holes to accept a 6-32 screw.
I removed and cut down the original bus bars, then soldered them to the new binding posts.
Tomorrow, I plan to replace the cheesy 20 AWG power cord and also replace the heat sink compound.
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