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Kustom Low Voltage power supply boards [message #25631] Sun, 02 October 2016 21:25 Go to next message
bsco is currently offline  bsco
Messages: 2
Registered: November 2012
Location: Canada
Junior Member
Question...New to the forum and a friend of mine has a Kustom head which had been worked on a long time ago....there is supposed to be a couple of small low voltage power supply boards but they have both been removed and a couple of 5W zener diodes are installed in it's place.....the voltage is around 10V but according to the schematic, they supply 23 volts.....these are missing like I had said....Anybody here know of were I can get them?? The owner would like to have this restored to it's original condition.....if at all possible....any help greatly appreciated....
Cheers
Re: Kustom Low Voltage power supply boards [message #25632 is a reply to message #25631] Mon, 03 October 2016 08:13 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4212
Registered: June 2004
Location: NY
Senior Member
It sounds like you have a K 200 A serise amp , as in these Amps the preamp sections run on a plus and minus 24 volts.
Unfortunately the only place your going to find those donor boards is out of another amp which may be a long search until you find one!
If your somewhat good with electronics you could build one new board and use modern regulator like a LM7824 and a LM7924, along with about 5 more bucks in parts and get regulators back in action in the amp.

These regulators can provide 1 amp of current which would be more than enough for the needs of the A series 200 head.
The only hard part is that these regulators need a little less input voltage then the 39 volts the k200 feeds the old regulators so a dropping resistor will be needed to get the input voltage to these regulators down to about 35 to 37 volts, and value of the resistor needed will have to be done by pure trial and error!

If you could do the above that I posted you might just as well built the two new boards from the schematics for the A amp in this sites tech section.

[Updated on: Mon, 03 October 2016 08:15]

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Re: Kustom Low Voltage power supply boards [message #25633 is a reply to message #25632] Mon, 03 October 2016 08:31 Go to previous messageGo to next message
bsco is currently offline  bsco
Messages: 2
Registered: November 2012
Location: Canada
Junior Member
Thank you very much for your input...I may have to go that route if I can't find them.....
Cheers
Re: Kustom Low Voltage power supply boards [message #25634 is a reply to message #25631] Mon, 03 October 2016 10:09 Go to previous message
stevem is currently offline  stevem
Messages: 4212
Registered: June 2004
Location: NY
Senior Member
you may have a simpler option of going with the regulator section from the power supply of a K250 amp who's schematic can be found on this site.
These amps have the same main voltage of a plus and minus 40 but the preamps use 12 volts.
Since you need 24 volts if you use a 100 ohm dropping resistor instead of the as built 200 ohm, and then place two 12 volt 5 watt Zener's in series for each rail of the supply that should get you the needed 24 volts with a lot less work!
I would still keep the dropping resistors at the K250 10 watt rating just to be really on the safe side .

[Updated on: Mon, 03 October 2016 10:10]

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