[TechAssist] Re: Power MOSFET - Huge Flash
- From: "Dan Williams" <wizhd@xxxxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Fri, 29 Jul 2005 08:09:44 -0500
Bad fet, ac rect leaky, or needs tab isolated?????
Wizard Electronics
Jacksonville, TX 75766
wizhd@xxxxxxxxxxxxxxxx
----- Original Message -----
From: "Bil Green" <tv.vcrrepair@xxxxxxxxxxx>
To: ".TECHASSIST @ freelists . org" <techassist@xxxxxxxxxxxxx>
Sent: Friday, July 29, 2005 3:30 AM
Subject: [TechAssist] Power MOSFET - Huge Flash
>I replaced a shorted MOSFET (driver in SMPS) and other parts
> (listed below) and as soon as the set was plugged in there was a
> huge flash (arcing) observed at the MOSFET and it shorted
> immediately.
>
> There is carbon between the metal clip and the plastic front (not
> the backside, and there is no crack visible in the plastic) of
> the MOSFET. I don't want to power it up again until I have a clue
> as to what is likely causing this (the original one didn't do
> this).
>
> I did use a TDA4605-2 (instead of -3) for U14101, and I can't
> imagine this caused enough voltage (thousands?) to create this
> large arc.
>
> With less AC voltage the set probably won't start so I rather not
> use this method.
>
> RCA PTV
> model P61929
> chassis PTK195ST
>
> Q101 (MOSFET) shorted
> U14101 melted
> R14125 burned
>
> Replaced 3 other resistors as recommended (checked OK)
>
> Bil
>
> PC 1000
> M-Pulse 5000 magnetic pulse generator
> http://magpulser.com
> Mammoth Lakes, CA
> 760-924-1000
>
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