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Kustom K 200 B-5 Troubleshooting [message #15729]

Mon, 30 May 2011 11:00

dr_zaius
Messages: 4
Registered: May 2011
Location: Texas

Junior Member

Ive had this thing since I was a teenager. It worked fine for years, but after sitting in storage for the last 5 or 6 years, I cant get it to do anything but power on. Ive hooked the head to a working cab, the unit powers on, I can hear the normal speaker hiss that all working amps put out, but no input sound can be heard on any channel. The knobs do absolutely nothing, save for the Bass knob on all 4 channels - turning any one of these makes that "dirty pot" crackling noise. I pulled the chassis out of the tuck and roll, nothing seems out of place or burnt out. This amp has reverb, but I can't even get a sound by tapping on the reverb can. Anybody out there in Kustom Land have a clue where to start troubleshooting?

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Re: Kustom K 200 B-5 Troubleshooting [message #15730 is a reply to message #15729]

Mon, 30 May 2011 14:17

cassent5150
Messages: 341
Registered: August 2009

Senior Member

Cut the playing field area by the test I PM'ed you. If you have sound (humm) by touching the base of Q700, you'll have to check voltages with your multimeter. You may have lost supply voltage (+ and or - 8 volt)to your pre amps.
Steve C

Steve C

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Re: Kustom K 200 B-5 Troubleshooting [message #15731 is a reply to message #15730]

Mon, 30 May 2011 14:45

dr_zaius
Messages: 4
Registered: May 2011
Location: Texas

Junior Member

I did the test and sent you a PM. Thanks for the help Thumbs Up

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Re: Kustom K 200 B-5 Troubleshooting [message #15732 is a reply to message #15731]

Mon, 30 May 2011 19:23

cassent5150
Messages: 341
Registered: August 2009

Senior Member

OK, so we can eliminate the output section and you have plus and minus voltage at the pre amps and if the second test to bypass the reverb board gets it going then we have the area located. I'm a rookie myself at this even though I've rebuilt/repaired several of these. This would be where you may want to get a schematic (with a layout of the circuitry if possible) and the guys with those talents can guide you. Your going to want to get a copy of PC-803 and you can get the schematics for that amp at the links below "FREE, JUST DOWNLOAD AND PRINT THEM OUT"

http://schematics.number26.org/index.php?dir=kustom/

or

http://music-electronics-forum.com/t19128/

Steve C

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Re: Kustom K 200 B-5 Troubleshooting [message #15733 is a reply to message #15732]

Mon, 30 May 2011 19:45

dr_zaius
Messages: 4
Registered: May 2011
Location: Texas

Junior Member

I dont think I ever found -8V at the preamp. I sent you a PM of my voltmeter readings.

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Re: Kustom K 200 B-5 Troubleshooting [message #15734 is a reply to message #15733]

Mon, 30 May 2011 20:58

cassent5150
Messages: 341
Registered: August 2009

Senior Member

That changes things, but explains some things also. OK we cant find any - voltage so we need to find out where its going. You should be able to test the caps for shorts if your meter has a continuity feature (with sound is a plus). You can also check most of the transistors also. I would suspect the small tantulum caps have dried out and drifted way out or are leaking it to ground. More than likely the one just left of Q700. I have had that one give me problems in a couple of my amps, but thats only guessing. Its going to take a little leg work to track it down for sure. If you can follow the schematic download and print off the PC-703 (Get the layout if possible also) from one of the links I sent you and start ckecking values on the negative side of the regulator components and see where your loosing it.

Steve C

[Updated on: Mon, 30 May 2011 21:03]

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Re: Kustom K 200 B-5 Troubleshooting [message #15736 is a reply to message #15734]

Tue, 31 May 2011 07:08

dr_zaius
Messages: 4
Registered: May 2011
Location: Texas

Junior Member

I suspect you are correct. I checked all the caps on the power board with the ohmmeter. The cap just left of the Q700 tripped the ohmmeter chime, all the other ones checked out okay. A few of them gave no reading, but none of them set the chime off on the meter. I sent you a PM with a pic attached that indicates where I found 8-v on the power board.

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