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Parasound 1200 II left channel static and....
Parasound 1200 II left channel static and....
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Old 30th May 2009, 03:03 PM   #11
john curl is offline john curl  United States
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Holco is normal feedback resistor.
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Old 30th May 2009, 06:57 PM   #12
nicoch58 is offline nicoch58  Europe
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burn trace PCB on Q123
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Old 30th May 2009, 07:01 PM   #13
john curl is offline john curl  United States
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You bet! Repaired by solder droplet.
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Old 30th May 2009, 07:16 PM   #14
nicoch58 is offline nicoch58  Europe
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Q123 not in short ?
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Old 30th May 2009, 09:53 PM   #15
john curl is offline john curl  United States
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Who knows?
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Old 30th May 2009, 09:57 PM   #16
john curl is offline john curl  United States
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BAD REPAIR JOB. CLEAN FLUX, MAKE BETTER CONNECTION AT Q123.
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Old 1st June 2009, 12:10 AM   #17
AJ Bertelson is offline AJ Bertelson  United States
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So I repaired the burned trace with solder joint/goober
Click the image to open in full size.
SJ did not touch the resistor to the left

No dice, still the same static. Is the burned trace indicative that it took out the entire channel? Also I lost my printout of the schematic but I will print out another one at work tomorrow. After I get another schematic I am going to try out the DMM. What is the process of elimination though that i should start with though? Should I start out with the center mosfets?
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Old 1st June 2009, 01:41 AM   #18
john curl is offline john curl  United States
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PLEASE, clean the dirty spots near the power transistors. Do it before, ever asking me anything again about this amp. AND please remember that I am its designer, not its builder!
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Old 1st June 2009, 01:43 AM   #19
nigelwright7557 is offline nigelwright7557  United Kingdom
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Quote:
Originally posted by AJ Bertelson
So I repaired the burned trace with solder joint/goober
Click the image to open in full size.
SJ did not touch the resistor to the left

No dice, still the same static. Is the burned trace indicative that it took out the entire channel? Also I lost my printout of the schematic but I will print out another one at work tomorrow. After I get another schematic I am going to try out the DMM. What is the process of elimination though that i should start with though? Should I start out with the center mosfets?

If its taken out a track then its like to have taken an output transistor(s) with it.
Check the output transistors for shorts.
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Old 1st June 2009, 01:47 AM   #20
john curl is offline john curl  United States
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CLEAN FIRST!
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