Kustom K100C-8

[ca7922303]

Well, what board is your amp? It will say on it.

The board that transistor was replaced on shows PC900, there is also a 1400 board and a 1500 board in this chassis. Wasn't expecting that?

[ca7922303]

1400, 900

[ca7922303]

Well, what board is your amp? It will say on it.

At any rate, schematic shows 4249s and this one has at least two(2) 2n4248s on it. It was working so maybe 48/49 no difference?

[Enzo]

The two types are in the same group, the 2N4249 is a 60v rated part versus 40v for the other one. There are other slight differences, but either will work here.

Each board has its own number. Power amp is one, preamps (channels) are others. SOme amps have two identical preamps, others have differing ones. Also some have reverb and some do not.

[ca7922303]

Can I get details on how and where to test? Thanks.

[52 Bill]

Do you know how to test a transistor junction with a multimeter diode test function? If you do, test the other 2N4248 transistor.

[ca7922303]

Do you know how to test a transistor junction with a multimeter diode test function? If you do, test the other 2N4248 transistor.

Replaced 2nd 2n4249 with new 2n4248 and no change in output. Original one dud not test same as new ones so I went ahead and replaced it.

[52 Bill]

How are you testing the transistors? I would start testing the rest of the transistors on the board.

Was the other one a 2N4249?

If you try and remove the board, then be careful of the bias diode that is clipped to the power transistor heatsink. The leads to that diode are very brittle and often break off. If that happens and the amp is powered up again, there can be major damage done to the transistors in the power amp.