Need your help once again group - set turns on, high voltage comes up,
get raster, and about 4 seconds later shuts down, but green power LED
on front stays lit. Can power off and back on, and the sequence
repeats. I've checked almost every cap, diode, resistor, and found
nothing wrong yet. Tried freeze spray also, but it doesn't seem to be
temp related. I suspect a shut down circuit, but I don't have the
schematic to troubleshoot. The B+ drops about 7V after power up,
otherwise is pretty stable. Anyone have experience or knowledge on
this particular model or problem? Thanks for any help.

I am not familiar with your particular model of TV. I can give you a
generic approach.

Did you use an ESR meter to check the caps??? The ESR spec is very
important!

I have had defectieve high voltage multipliers in TV sets also cause
what you are describing This part is usualy part of the flyback
assembly. In some models of TV sets it is a separate module. In the
case of this module going defective, the power supply can be put in to
the protection mode.

If there is a scan failure or some area that is pulling too much
current this can cause the power supply to go in to the protection
mode.

I would guess you carefully inspected the set for any cold solder
connections and any connectors that are not making proper contact.

The other solution would be to get the service manual from the
manufacture's parts distributor and spend the time to troubleshoot the
set with a DVM and scope.


Jerry G.

__

On Jan 30, 5:34*pm, wrote:
Need your help once again group - set turns on, high voltage comes up,
get raster, and about 4 seconds later shuts down, but green power LED
on front stays lit. Can power off and back on, and the sequence
repeats. I've checked almost every cap, diode, resistor, and found
nothing wrong yet. Tried freeze spray also, but it doesn't seem to be
temp related. I suspect a shut down circuit, but I don't have the
schematic to troubleshoot. The B+ drops about 7V after power up,
otherwise is pretty stable. Anyone have experience or knowledge on
this particular model or problem? Thanks for any help.

On Jan 30, 10:43*pm, "Jerry G." wrote:
I am not familiar with your particular model of TV. I can give you a
generic approach.

Did you use an ESR meter to check the caps??? *The ESR spec is very
important!

I have had defectieve high voltage multipliers in TV sets also cause
what you are describing This part is usualy part of the flyback
assembly. In some models of TV sets it is a separate module. In the
case of this module going defective, the power supply can be put in to
the protection mode.

If there is a scan failure or some area that is pulling too much
current this can cause the power supply to go in to the protection
mode.

I would guess you carefully inspected the set for any cold solder
connections and any connectors that are not making proper contact.

The other solution would be to get the service manual from the
manufacture's parts distributor and spend the time to troubleshoot the
set with a DVM and scope.

Jerry G.

__

On Jan 30, 5:34*pm, wrote:



Need your help once again group - set turns on, high voltage comes up,
get raster, and about 4 seconds later shuts down, but green power LED
on front stays lit. Can power off and back on, and the sequence
repeats. I've checked almost every cap, diode, resistor, and found
nothing wrong yet. Tried freeze spray also, but it doesn't seem to be
temp related. I suspect a shut down circuit, but I don't have the
schematic to troubleshoot. The B+ drops about 7V after power up,
otherwise is pretty stable. Anyone have experience or knowledge on
this particular model or problem? Thanks for any help.- Hide quoted text -

- Show quoted text -

Sorry for the late reply, and thanks for the info. I have not checked
ESR on caps yet. I don't think my old Sencore checks them in circuit,
which makes parelleling as easy, but not sure where to focus. I have
suspected a shutdown circuit, but without the manual, I can only check
component to component. I will have to find a schematic, and dig
deeper. I have checked and resoldered many joints, but no change. I'll
post an update. Thanks again for the info.