kustom 150 woe... [message #22838] |
Sun, 03 May 2015 11:33 ![Go to next message Go to next message](/FUDforum/theme/vk30/images/down.png) |
pinkjimiphoton
Messages: 45 Registered: May 2015 Location: the dark side of the moon
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try 5. jesus.
bought a k150 head, the 3052 board is BURNED. the traces are still there, but the fiberglass is just carbon,
i DID pick this up strictly for spare parts, but do ya think it may be fixable?
i'm posting this NOW before it dumps my post for a 5th time... pix imminent.
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Re: kustom 150 woe... [message #22841 is a reply to message #22838] |
Sun, 03 May 2015 14:03 ![Go to previous message Go to previous message](/FUDforum/theme/vk30/images/up.png) ![Go to next message Go to next message](/FUDforum/theme/vk30/images/down.png) |
chicagobill
Messages: 2005 Registered: April 2003
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It's burnt pretty badly, but I've seen worse. I think that it could be fixed. You might have to run a trace or two away from the board just to be safe, but solid state amps don't run at voltage levels high enough to make carbonized board areas too much of a factor.
You need to grind away as much of the burned board as possible. Some of that black is just soot on the surface. The sections that are burned through the fiberglass are the real problem. I've sometimes made patches of pc board with the traces replicated and epoxied them together. Then all you have to do is to solder the traces together where they meet.
I did have one that had a board so badly burnt, that it was easier to just reproduce the entire board. I created an iron down resist pattern and etched a new board. Of course that was an extreme case.
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Re: kustom 150 woe... [message #22853 is a reply to message #22849] |
Mon, 04 May 2015 16:39 ![Go to previous message Go to previous message](/FUDforum/theme/vk30/images/up.png) ![Go to next message Go to next message](/FUDforum/theme/vk30/images/down.png) |
chicagobill
Messages: 2005 Registered: April 2003
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Senior Member |
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The burnt board was caused by the bypassed fuse. The resistors burn because of a shorted transistor. The transistor shorted because of a shorted speaker output or because of a huge power surge or because the temp diode broke a lead or because it got too hot or because somebody sneezed in the clean room when the transistor substrate was being manufactured...
There are millions of reasons why these things fail some explainable and some not. The real problem was caused by the idiot that bypassed the fuse with a solid wire.
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Re: kustom 150 woe... [message #22860 is a reply to message #22838] |
Mon, 04 May 2015 17:41 ![Go to previous message Go to previous message](/FUDforum/theme/vk30/images/up.png) ![Go to next message Go to next message](/FUDforum/theme/vk30/images/down.png) |
chicagobill
Messages: 2005 Registered: April 2003
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Senior Member |
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I test transistors with a multimeter.
The Vaseline like goo is heat sink grease, used to help transfer heat to the diode case.
Every transistor and diode in the power amp section should be tested. Same thing for the resistors. The power supply diodes need to be tested as well. There's no way for you to figure out why it died, because there is no way to know what single part failed first.
In a lot of cases, one output transistor will short which causes the fuse to blow before any other part is damaged. When the fuse function is disabled, the shorted transistor draws too much current from the driver stage and power supply causing the driver transistor to short which causes the emitter resistors to burn, etc., etc., etc.
As long as the power supply can supply voltage to the circuit, parts will continue to burn or short until a resistor or pc trace burns open circuit and cuts off the voltage to the amp or the power transformer dies.
Have you tried powering up the amp yet? Do you have a light bulb limiter?
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Re: kustom 150 woe... [message #22873 is a reply to message #22871] |
Tue, 05 May 2015 09:47 ![Go to previous message Go to previous message](/FUDforum/theme/vk30/images/up.png) |
pinkjimiphoton
Messages: 45 Registered: May 2015 Location: the dark side of the moon
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hmmm, def a k 100, of course the guy i bought it from called it a frank. it was just the chassis. i didn't really care, i just wanted
a kustom at the time.
my girl brought me a beautiful minty k200 for christmas, the one with the transfomers ripped off is still under my bench awaiting resurrection.
i've got a head piece cab that was supposed to be for yet another one, but nothing i have will fit in it. just a little too short and not quite wide enough to fit aything i have.
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