[TechAssist] Re: Sharp VCR VC-H972U - SMPS Dead
- From: Edward Gaidies <teltek3@xxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Tue, 24 Aug 2004 20:14:00 -0400
Yup..I feel the same way. I guess I better get educated on these, looks
like they are going to be around for a while. Got a couple of Toshiba's
on the bench, as we speak. Problem in SMPS.
-Ed-
Ed Gaidies
Tel-Tek Electronics
Ontario-Canada
teltek3@xxxxxxxxxxxx
On 24-Aug-04, at 3:11 PM, David Lessard wrote:
> Hi Techs,
>
>
> Let me be the first to tell you all that I really haven't had great
> luck
> repairing SMPS's lately. VCR came in dead, apparently after a hydro
> outage, when the power came back on primaries on two other appliances
> were open and this VCR's SMPS was dead. Fuse was blown, main switching
> transistor and driver transistors on the primary are OK yet the fuse
> blows on AC plug-in. I've checked ALL diodes and transistors,
> everything
> tests OK. Base of the main switching transistor has .7VDC on it all the
> time, so this transistor is "ON" all the time, hence the blowing fuse.
> I
> need more information on these SMPS's, I.e. Where do the switching
> pulses derive from? If anyone has a schematic on this SMPS, please send
> it along.
>
>
>
> Thank-you
>
>
>
> David Lessard
>
> Alexandria, Ontario. Canada
>
> mr_fixit@xxxxxxxxxxxx
>
>
>
>
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