[TechAssist] Re: Mitsubishi VS-4551C chassis VZ2 No start up
- From: "Tel-Tek Electronics" <teltek3@xxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Thu, 30 Oct 2003 07:46:51 -0500
Warren;
If you can send me the part # of the "Main Circuit" I'll check with Mits in
Markham, and see if it's available. May not be cost effective.
-Ed-
Tel-Tek Electronics
Ontario-Canada
teltek3@xxxxxxxxxxxx
----- Original Message -----
From: "Warren C." <warrenca@xxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Thursday, October 30, 2003 12:40 AM
Subject: [TechAssist] Re: Mitsubishi VS-4551C chassis VZ2 No start up
> Leonard
> I've checked today with the scope on the secondary diodes and my
suspicions were
> confirmed.
> No activity thru the transformer at all.
> The main regulator has almost a sine wave form bouncing up and down
slightly on
> pin 5.(About 40V PP)
> I believe that this pin should have a flat pure dc voltage on it about 20
V
> All the primary caps have been changed and the resistors have been
checked.
> As noted earlier the regulator has been changed too. Also D9A00 with no
effect.
> The SM will simply not start up. Mits suggested today disconnecting the
secondary
> outputs
> one at a time to see if any are loading the circuit up.The turn on PS
seems ok
> and the relay seem to be
> OK too.
>
> Is there a trouble shooting flow chart available for this SMPS??
> Does anyone know if the whole Main circuit is available for purchase or
> exchange??
>
> Thanks for your response
>
> Warren C.
>
> Leonard Caillouet wrote:
>
> > 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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