[TechAssist] Re: Power MOSFET - Huge Flash
- From: "Paul Westcott" <westcott@xxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Fri, 29 Jul 2005 09:20:37 -0400
Bil,
Check for an open R14146 (380 k) or R14145 (270 k)
If these are bad, the MOSFET will literally explode when the set is plugged
in.
HTH
Paul Westcott
Kingsway Electronics
1090 Kingsway
Sudbury, Ontario
Canada
Phone 705 566-9290
Fax 705 566-5349
westcott@xxxxxxx
----- Original Message -----
From: "Bil Green" <tv.vcrrepair@xxxxxxxxxxx>
To: ".TECHASSIST @ freelists . org" <techassist@xxxxxxxxxxxxx>
Sent: Friday, July 29, 2005 4:30 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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