F5 Toshiba Output bias Issue - Page 2 - diyAudio
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Old 6th March 2014, 03:18 PM   #11
DGreen is offline DGreen  United States
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Join Date: Feb 2009
Location: Seattle,WA
Thanks for the responses and help. Will check out voltages this weekend.
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Old 9th March 2014, 06:21 AM   #12
DGreen is offline DGreen  United States
diyAudio Member
Join Date: Feb 2009
Location: Seattle,WA
Success!! I thought a little more deeply about this build verses my previous F-5 build. I used the same type of board (CViller V-2-had an extra set). I compared the old boards with the new populated board and the components were all in order and matched the old board. The only difference on the new build were different output FETs and the use Artic Silver instead of silicone grease. I was pretty sloppy with the application of Artic Silver and when I pulled the FETs off of the heatsink to check there was a glob of the Artic that had squeezed out on the side of the FET and was in contact with the heatsink. Also, the Artic was on the screw that held the FET in place. I had checked for short between the drain and heatsink before I pulled off the FET and my meter didn't read a short. Hmm? I cleaned off the Artic Silver and used silicone grease and Alum oxide insulators and replaced the FETs, fired up one channel and the die of the FET measured 49 degress centigrade after about 1/2 hour or so. D/C offset 4 mV at .595V across R11 and 12.
I don't want to "diss" Artic Silver and it is not supposed to be electrically conductive, but I won't use it again for this type of application. Thanks guys for helping me with this. Greatly appreciated.
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Old 9th March 2014, 06:50 AM   #13
The Dastardly Dad of Three
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Join Date: Sep 2009
Excellent news - well done !
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