[TechAssist] Re: Mitsubishi VS-4551C chassis VZ2 No start up
- From: "Leonard Caillouet" <lcaillo@xxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Wed, 29 Oct 2003 07:42:43 -0500
There are some modifications, as noted in another reply. I find it curious
that you don't know whether the SMPS is "coming up at all". You might want
to do some research on how switching power supplies work and how to
troubleshoot them. If you have no oscillation at the primary, just the
165vdc, it isn't running. You can easily check to see if a SMPS is running
by looking at the rectifiers in the secondary. No voltage on any means no
running. Beyond that you need to check the obvious first, like electrolytic
caps, open resistors etc. Beyond that you need to look at the specifics of
the circuit.
In general, if it is a Mitsubishi from the early to mid 90s check for leaky,
high ESR, and high DA caps throughout the set. Also check carefully for CRT
coolant leakage.
Leonard Caillouet
Electronics World
----- Original Message -----
From: "Warren C." <warrenca@xxxxxxxxx>
To: "techassist" <techassist@xxxxxxxxxxxxx>
Sent: Wednesday, October 29, 2003 12:37 AM
Subject: [TechAssist] Mitsubishi VS-4551C chassis VZ2 No start up
> Hi all
>
> This TV I must revisit
>
> TV relay clicks when you press on and the voltage on the primary bridge
> and cap come up to
> about 165 V dc. This voltage stays up until you turn the set off. We
> have changed the main SM regulator
> on the primary side and the opto and the 130V reg. on the secondary side
> to no avail.
> The voltage on pin 1 of the main regulator comes up to 165v when you
> turn the set on. THis Voltage comes thru
> Pin 9 of primary windings. We don't think that the SM PS is coming up at
> all.
>
> Does any one have ideas or experience with this set ?? TIA We have the
> schematic now....
>
> All hints are welcome
>
> Warren Campbell
> Campbell's TV & Appliances
> Cannington
> Ontario
> Canada
>
>
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