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Help me find why my resistor keeps blowing [message #1399] Wed, 27 March 2002 09:44 Go to next message
Anonymous
Ok, this is a very technical post. For any of you who have the schematic for the K250, you will need it. On the Power board PC5065 I replaced a bunch of resistors that where blown. Now every time I power on the amp I blow R27. I have replaced it and blown it about 3 times now. I'm figuring that there is something wrong with one of the other parts that keeps blowing this resistor. Any help would be great. Thanks!
Re: Help me find why my resistor keeps blowing [message #1415 is a reply to message #1399] Fri, 12 April 2002 07:55 Go to previous messageGo to next message
Anonymous
I do have a circuit lay out, but not here at work. If your bad reisitor is on the output driver board,(the board mounted on the bottom of the amp) and is one of the large 5 watt resistors next to each driver transistor with the retangular heat sink. These are the output transistor emiter resistors. These blowing mean you have at least one bad output transistor, and one bad driver transistor.If this is the resistor you speak of its value is .51 ohms, half and ohm not 51 ohms. A .47 ohm will also work and is more common to find. let me know. Steve.
Re: Help me find why my resistor keeps blowing [message #1495 is a reply to message #1399] Fri, 10 May 2002 07:53 Go to previous messageGo to next message
Anonymous
Hi. resistors do not short out unless another componet is bad,(ie) a cap or most likly a transistor. unless you are tech you should take the amp to a known good music repair shop in your area, or even a TV repair shop. All parts to repair this amp are still avalable. let me know how you are making out.
Re: Help me find why my resistor keeps blowing [message #1496 is a reply to message #1399] Fri, 10 May 2002 12:58 Go to previous message
Anonymous
For what it's worth, I agree. R27 is only supposed to have 5/100 of a volt across it, certainly not enough to burn up a 1/2 watt resistor. The only significant source of the voltage (and current) necessary to do this that I can come up with is a shorted output transistor like either Q12 or Q13 in combination with a mix of open and shorted resistors. There is a bunch that would need to be checked out and verified.
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