Apply new grease and reassemble.įor a minor cosmetic upgrade I took off all the external stainless cap screws and replaced them with button head black oxide allen head scres. Test every transistor, replace any open emitter resistors with the same type (fusible safety resistor), and clean off all the old heat sink grease. Take every power stage heatsink assembly off the chassis and disassemble them. For the caps on the preamp board, use Vishay 10,000 hour rated parts. Replace every electrolytic capacitor OTHER than the main reservoir caps which are computer grade and may last another 50 years. Use a dynamic transistor tester to check all the driver transistors on the driver board, and if any of them are blown, you'll need to check all six transistors oin the heatsinked power module that's connected to that driver board.Īt this point, those amps being 30 years old now, you should perform the following maintenance:Ĭlean and use deoxit on all cables and connectors on the driver boards. Compare the 80 and the 160 side by side with the top covers off and it's super easy to see what needs to be done. You'll need to obtain or make a cable with the appropriate Molex connectors and pins, and suitable wire, to jumper the former left channel into the right channel for mono operation. What's working, or not working, about the 160 you've got?Ĭonverting the other KSA-80 to a 160 is simple, and it gives you a spare preamp board to put into the broken 160 if the problem with the 160 is in that board.
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