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Forum: Repairing Kustom Amps
 Topic: K200A-1 Power Amp Rescue Needed
Re: K200A-1 Power Amp Rescue Needed [message #27260 is a reply to message #27251] Sun, 21 April 2019 06:06
stevem is currently offline  stevem
Messages: 4148
Registered: June 2004
Location: NY
Senior Member
Yes, the sperate pc502 and pc602 are only used in the A serise amp, in the B series amps they where put on the pc703 board which is a combo regulator and driver board.

The A model preamps run on a + and - 23 volts and as in the later B series amps the negitive regulators output tracks the positive regulator.

This all means that the - 23 volts will never be correct if the positive regulators output is not right.
Both of these boards have 15 volt electrolytic caps that will short out if Transistors on the board are bad and thus smack the caps with way more voltage then they are rated at..

Note that if you go into our tech section and choose the pc board listing you will atleast find schematics for all the versions of your 702 board and the schematic for a 502 board which it would seem your missing!

I guess you can bread board yourself one, but first let's get the amps driver and output stage up and running.

Just for now I would unhook the 34 volt power supply wire from the regulator board that you do have .

PS, by the way there's no such thing as a vintage era Kustom bass head, they where just non effects heads and had a normal and brite channel.

[Updated on: Sun, 21 April 2019 06:25]

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