Harmon/Kardon PM635 HiFi Amplifier Restauration
Mostly Original State
At this point the rear speaker terminal was already broken and new speaker ports had already been installed. Also the plastic sleeve of one of the big filter caps had been removed.
Renewing the Transistor's Cooling Paste
After reassembly I made sure that the transistors were electricly isolated from the heatsink, of course.
All new Electrolytic Caps
The new filter caps are Nichicon GU series aluminum electrolytic capacitors (6800uF / 50V). All other caps are Panasonic FC, Nichicon GU and Nichicon VK series caps.
All of the bigger caps were secured with some non acidic silicone. It doesn't look very pretty but it prevents the caps from vibrating when the chassis is vibrating - e.g. during transport.
New Line Filter Cap
The original line filter cap was one of the infamous RIFA caps (see "RIFA madness") so it had to be replaced with a shiny new WIMA X2-rated cap.
New Power Cord
The isolation of the power cord was slightly damaged so it also needed to be replaced.
Rear View
I've also replaced the original speaker terminal and replaced it with an aluminum plate which I painted black. The new speaker ports support both bare cable ends and 4mm banana plugs.
Front View
All four trim pots behind the round knobs were thoroughly cleaned with electrical contact cleaner spray. Now they don't create any scratching noises anymore when being turned.
And last but not least the face of the amplifier was cleaned until the cows come home.
