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Kustom 400 Schematic [message #15524]

Sat, 16 April 2011 01:28

haljones
Messages: 2
Registered: September 2010
Location: North Mississippi

Junior Member

Does anyone on the forum have a schematic on a 400 you could share with me? Got one with a shorted bridge rectifier that is huge and I need to know the power rating on it so I can order one with the correct amperage. The filter caps off the bridge have decreased in value from 9000uf to less than 1000 each. I should be able to just replace them with some new 10k@50v and be OK. Can anyone help me out with a print on this one? Thanks!

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Re: Kustom 400 Schematic [message #15525 is a reply to message #15524]

Sat, 16 April 2011 09:32

cassent5150
Messages: 341
Registered: August 2009

Senior Member

If its the TRB400 you can print one from the bottom of the list at the link below

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

Steve C

Steve C

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Re: Kustom 400 Schematic [message #15526 is a reply to message #15524]

Sat, 16 April 2011 10:18

stevem
Messages: 4730
Registered: June 2004
Location: NY

Senior Member

Hello.
A commom bolt down type 15 or 30 amp rated bridge recto like Radio Shack stocks is more than enough to use as a replacement as these amps pull no more than 6 amps at best as I recall.

Voltage vise 150 volts in rating is fine, just make sure to use heatsink compound when bolting it back up to the chassie.

Your choise for replacement filters is good to go also, but if your wallet can handle it a 75 volt rating will last longer and handle line voltage surges better.

[Updated on: Sat, 16 April 2011 10:19]

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Re: Kustom 400 Schematic [message #15528 is a reply to message #15526]

Sat, 16 April 2011 15:33

cassent5150
Messages: 341
Registered: August 2009

Senior Member

I got a pair of 9000uf 75V malorys of ebay for cheap. might be worth a look. (THEY WERE NOS)

Steve C

[Updated on: Sat, 16 April 2011 15:38]

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Re: Kustom 400 Schematic [message #15529 is a reply to message #15524]

Sat, 16 April 2011 15:57

stevem
Messages: 4730
Registered: June 2004
Location: NY

Senior Member

NOS(unused old) electrolytic type caps are like buying NOS 20 year old new but dry rotted tires for your car, steer clear of them!!!!

[Updated on: Sat, 16 April 2011 15:58]

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Re: Kustom 400 Schematic [message #15531 is a reply to message #15529]

Sat, 16 April 2011 21:16

cassent5150
Messages: 341
Registered: August 2009

Senior Member

Well, I'll take that advise and run with it!! I here everyone bragging about NOS this and NOS that as if it were a good thing so thats what I thought. Ain't education cool!!!! Thanks

Steve C

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Re: Kustom 400 Schematic [message #15532 is a reply to message #15525]

Sun, 17 April 2011 01:28

haljones
Messages: 2
Registered: September 2010
Location: North Mississippi

Junior Member

Appreciate all of the replies. Don't think this one is a TRB400 though. The power transformer only has a single output winding that is center tapped and has 31v from each outside leg to the center tap. The way it is wired to the filter caps looks to be configured that way to get the +31v and -31v needed for push-pull outputs. The bridge had me a little worried because I couldn't cross reference it or pull up a datasheet on it. Thanks for the info guys.

[Updated on: Sun, 17 April 2011 01:29]

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Re: Kustom 400 Schematic [message #15539 is a reply to message #15524]

Mon, 18 April 2011 12:59

chicagobill
Messages: 2005
Registered: April 2003

Senior Member

I can't help with the schematic, but I do know that the amp is basically two K200B power amps in a single chassis. That being said, I would guess that the bridge rectifier should be rated at a minimum of 6-10 amps at 100 volts.

In our shop, we only stock two bridge rectifiers and they will replace most every one that we come across on guitar amps. One is a small epoxy pc unit rated 10 amps at 200 volts and the other is a large metal cased block that is rated at 25 amps at 250 volts.

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Re: Kustom 400 Schematic [message #15540 is a reply to message #15524]

Mon, 18 April 2011 18:40

stevem
Messages: 4730
Registered: June 2004
Location: NY

Senior Member

Yours is a K400 model, not a TRB400 as I own that model and bought it new in 2000.
With your new recto bridge in place you be reading a positive and negitive 39 to 40 volts at the filters with the amp idling.

From what you posted you have a total of 62 volts across the legs of your power transformer, this should be much closer to 100 volts with both leads not feeding/powering anything.

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