VintageKustom.com: Repairing Kustom Amps

Re: k200b-3 questions [message #11695 is a reply to message #11684]

Sat, 29 August 2009 14:55

chicagobill
Messages: 2005
Registered: April 2003

Senior Member

Welcome!
The bright channel pre-amp PC203 is designed with an added bright boost circuit that uses a bypass switch for the bright knob. If the switch becomes intermittent and does not make clean contact it will kill the signal through the pre-amp. Try switching it back and forth a few times and see if the sound is restored.

The Boost channel board PC403 has the selective boost and the harmonic clipper circuit. If you hear the noise from the boost switch, then that circuit is probably working. The noise is probably caused by a cap that is switched in the circuit that has a slight charge built up in it. Turning the switch causes the cap to discharge as it is being placed in and out of the circuit.

Have you tried switching on and off the clipper control? The clipper circuit falls between the boost and the pre-amp input stage. If the switch on the control is not clicked off the bypass circuit will not work.

If you have dc on the output, you will need to have the power amp looked at. If you have a voltmeter, see if there is any dc on the output jack (no speaker hooked up). I don't know what you were doing when the spark happened, but you should not have the amp on while connecting the speaker cable.

As for the pilot lamp, it will not cause any problems if it is missing the bulb. Just be sure to replace it with the correct one when you want to.

Buzz in the speakers is rarely caused by bad jacks or wiring. It is possible, but unlikely. Do both speakers sound the same? Is it something loose in the cabinet that could be buzzing?

Hope this helps.

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