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Old 17th July 2007, 02:30 PM   #1
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Default Aleph-x hot source resistor

Hi

Iím half through starting up my Aleph-x (100 w). The problem I have right now is one of my source resistors is getting to hot, over 90 C. Voltage over them, its four resistors is if I remember it correctly 0.54 V. Iím not with the amplifier right now.
Iím sure the solution is out there and Iíve spent yesterday going over treads and Iím going to look for it. But if you know what the solution is it would help me a lot.
So far I have come up with the following possible faults.

- Problem with the PCB. I donít think so because Iím using this board: http://www.kk-pcb.com/amps.html . It should be ok.
- A broken mosfet- hopefully not. I donít want to resolder it again for the fifth or tenth time.
- Badly matched mosfet- hopefully not. The voltage over the source resistors are the same.
- Maybe there something with the bias current- I havenít looked in to that yet.
- Broken silpad
- Bad soldering

Maybe all the source resistors have more then 90 C. I have to look in to that.
Anyway itís not ok.

I have more question but I think Iíll leave it for later.
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Old 17th July 2007, 02:33 PM   #2
Magura is offline Magura  Denmark
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90C for a power resistor is not all that hot....


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Old 17th July 2007, 06:46 PM   #3
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The transistor was 75 C. Much hotter then the others.
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Old 17th July 2007, 10:21 PM   #4
Magura is offline Magura  Denmark
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then try replacing the fet that runs warmer, but keep the initial installed fet to be able to put it back if there is no change.

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Old 18th July 2007, 03:37 PM   #5
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one time i did the some mistake
i wire the g directly to the resistor and the resistor got hot so you can try to find out about the wireing you have
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Old 19th July 2007, 02:15 PM   #6
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Right now Iím waiting for a new PCB. The old one has been re soldered too many times.
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Old 19th July 2007, 02:26 PM   #7
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Right now Iím waiting for a new PCB. The old one has been re soldered too many times.
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