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Schematic for Kustom 4-10L-4? [message #18032]

Fri, 11 January 2013 18:55

blahseanblah
Messages: 6
Registered: January 2013

Junior Member

Hi all, I am trying to repair a kustom 4-10L-4 with the K200A power amplifier. Since the schematic section is down I thought I would ask here for a schematic. If you have some documents that might be able to help I would really appreciate a copy. Thanks

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Re: Schematic for Kustom 4-10L-4? [message #18033 is a reply to message #18032]

Fri, 11 January 2013 19:13

pleat
Messages: 1454
Registered: June 2004
Location: Belding, Mi

Senior Member

Your amp head is a K200A-4. The 4-10L is actually the cabinet model of 4x10" JBL speakers. Kustom for a short time was using the retail price and the type of cabinet for model numbers.
I don't have the schematics, but I'm sure one of the tech guys would have it.
pleat

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Re: Schematic for Kustom 4-10L-4? [message #18035 is a reply to message #18032]

Sat, 12 January 2013 10:29

stevem
Messages: 4775
Registered: June 2004
Location: NY

Senior Member

Hi, PM me your fax number, email adress and or mailing adress and I will get you out a copy.
What is the issue you are having with the amp?

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Re: Schematic for Kustom 4-10L-4? [message #18036 is a reply to message #18035]

Sat, 12 January 2013 12:24

Kustom_Bart
Messages: 601
Registered: October 2010
Location: Greenville, MichiGUN

Senior Member

PM sent Steve

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Re: Schematic for Kustom 4-10L-4? [message #18037 is a reply to message #18036]

Sat, 12 January 2013 13:40

blahseanblah
Messages: 6
Registered: January 2013

Junior Member

PM sent

I picked the amp up for free yesterday. The gentleman I got it from said he turned it on and "one of the resistors or caps started smoking from the back". It had been sitting for years apparently.

I opened it up at my place and did a quick visual inspection and I couldn't find any obviously burnt components. I also couldn't do play test because I don't have a cab for testing (I live in a reaaaaal small apt.)

Are there certain things to look out for with these amps?

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Re: Schematic for Kustom 4-10L-4? [message #18038 is a reply to message #18032]

Sat, 12 January 2013 23:05

chicagobill
Messages: 2006
Registered: April 2003

Senior Member

Yeah, you have to be real careful with that amp. First they start to smoke, and then they will explode into flames. I think that you should send it to me, cause I know how to safely dispose of them. Rolling Eyes

That is a very popular amp, as it was the model that Creedence Clearwater Revival played.

As long as you don't have a speaker hooked up to it, the power amp will not draw enough current to cause anything to burn, unless there is a major problem like a shorted transistor. Most amps that have been sitting just need to be cleaned up and sometimes a few caps will need replacement.

Okay, the most important question, what color is the T&R?

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Re: Schematic for Kustom 4-10L-4? [message #18041 is a reply to message #18038]

Sun, 13 January 2013 04:12

blahseanblah
Messages: 6
Registered: January 2013

Junior Member

The amp is blue. Is that a good thing?

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Re: Schematic for Kustom 4-10L-4? [message #18052 is a reply to message #18032]

Mon, 14 January 2013 12:41

chicagobill
Messages: 2006
Registered: April 2003

Senior Member

I like blue. Is it blue or is it blue/green, which is called Cascade?

Colors are rarer than black, but CCR used black T&R amps. Kustom guys will like the blue, but CCR guys would prefer black. Players don't really care as long as the amp sound good.

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Re: Schematic for Kustom 4-10L-4? [message #18061 is a reply to message #18052]

Wed, 16 January 2013 22:06

blahseanblah
Messages: 6
Registered: January 2013

Junior Member

It's just blue. Man I can't wait to get this thing running... Thanks for all the help you guys.

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Re: Schematic for Kustom 4-10L-4? [message #18062 is a reply to message #18061]

Wed, 16 January 2013 22:22

pleat
Messages: 1454
Registered: June 2004
Location: Belding, Mi

Senior Member

Just a reminder, on the K200A-4 heads or any of the K200A series amps with effects, you need the footswitch to operate them. Easy fix is to short to ground all the wires at the footswitch jack and the effects will then be controlled by the controls on the front panel.
pleat

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Re: Schematic for Kustom 4-10L-4? [message #18112 is a reply to message #18032]

Tue, 29 January 2013 19:57

blahseanblah
Messages: 6
Registered: January 2013

Junior Member

Looks like steve wasn't able to find his. If anyone else has the schematic please send me a PM. Thanks again everyone for your help, advice, and time.

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Re: Schematic for Kustom 4-10L-4? [message #18179 is a reply to message #18112]

Thu, 14 February 2013 02:12

blahseanblah
Messages: 6
Registered: January 2013

Junior Member

It lives!

Turns out one of the 100 ohm resistors in the power supply was burning up because of a shorted power amp transistor. After replacing these components I found that the harmonic clipper and selective boost weren't functioning. This took a whole day to figure out because I didn't realize that the board holding the circuitry for these two effects had some long wire leads underneath that were making contact with the chassis when the board was fully mounted. UGH! Plus, it didn't help that I ended up trashing two preamp transistors while poking around...

This amp has boards that I had trouble finding info about on the web. They were sort of similar to the smattering of schematics that are available for the other amps. They were:

PC103 - Preamp
PC302A and B - Trem and Reverb
PC402 and B - Clipper and Boost
PC702 - Power Amp

There were also two mystery boards next to the power amp that didn't have a marking.

Glad it's working. I'm gonna measure the output resistance for this guy and then it's off to craigslist or ebay. Thanks again for the help.

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Re: Schematic for Kustom 4-10L-4? [message #18180 is a reply to message #18032]

Thu, 14 February 2013 12:28

chicagobill
Messages: 2006
Registered: April 2003

Senior Member

Glad to hear you got it working. The two small boards next to the power amp are the +&-24 volt power supply regulators for the preamps.

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