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Repositioned and tighten up my VRM mount today to close up the amp unfortunately I didn't check the continuity sure enough when I hit the stand-by switch I blew a fuse. Checked the continuity and sure enough the middle contact on the MOSFET was hot, I must have screwed the mounting screw too hard or twisted it because there was a rip in it around the mounting hole. I think everything else survived but I need another SIL pad is there anything else that would work. This may be a wild shot but I noticed my wife has silicone baking sheets made of thicker silicone would something like that work? How about Heat Sink compounds sold locally. JGK

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JGK

Actually it sounds like the MOSFET blew and took out the fuse. But to try again, you need a mica washer & heatsink compound or another thin Sil Pad. These are a bit hard to find because of the size of the FET.

If you lift the device right off chassis, and startup again, you'll know if the FET is blown because it will take out another fuse. Then you're almost back to square one.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Can I purchase a compatible FET locally? What are the specs? JGK

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JGK

Test and if you need one, email me.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Hey JGK...


The main purpose of the Silpad (or the mica/thermal compound) is for a more efficient heat transfer between the MOSFET and the chassis, which is our heatsink in this case. Too thick a silicone material will insulate the MOSFET from the chassis and essentially do nothing thermally. I've read that we also need to isolate the MOSFET electrically from the chassis which the Silpad or mica will do as well.
To isolate the MOSFET completely may require the addition of small shoulder washers to assure that the mounting screw is also isolated from the MOSFET's heatsink, since the screw is hard mounted to the chassis via a lock washer and nut. (I've never confirmed that the MOSFET really needs to be electrically isolated). There appears to be enough clearance of the MOSFET heatsink to prevent this, but if you're concerned about things shifting this would be some extra insurance.
A piece of Kapton or electrical tape just under the eyelets and wiring of the VRM wouldn't hurt either.

Joe G

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Some assembly required,
Brain sold separately...

Checked everything out this morning the FET was OK I checked the SIL pad it was torn around the screw hole. I reversed it and carefully reattached it and all seems to be working OK is there anywhere I can pick up an extra SIL pad or SIL material? Thanks for the help. JGK

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JGK

JGK
If you get desperate, PM me your address and I'll get one to you. I'm glad your equipment wasn't damaged

Joe G

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Some assembly required,
Brain sold separately...

In this case, not required.

Glad it all worked out. I'd say you are lucky! I have a mica insulator & I can send a squirt of grease as well. The Sil pads (which jv sent - you can thank him) are the easiest to use.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Jim, a new Silpad is on the way...

Joe G

_________________
Some assembly required,
Brain sold separately...

Thanks allot and thanks for all the info to keep my amp cranking. JGK

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JGK