Prev: RCA 36V430T Chassis ITC008HYN turns on and off repeatedly.
Next: TV's EHT wants to jump
From: Gary L. Woodruff on 5 Nov 2009 11:04
howdy, I have this monster RCA that is possessed. It will turn on and
then at random intervals will shut down and power back up. I have
touched up any solder connections that looked cold. I removed all of the
tact switches from the front panel control, problem still exists. I
disconnected the front panel after the set was powered on and still get
shutdown/startup. the set does not stay on long enough to develop raster
but does have the HV static on the screen. I am thinking it is the power
IC but do not have a print. Any and
all help is greatly appreciated.

thanks, Gary
From: ian field on 5 Nov 2009 13:15

"Gary L. Woodruff" <woodruffrepair(a)frontiernet.net> wrote in message
news:VHCIm.10450$fE2.9546(a)newsfe04.iad...
> howdy, I have this monster RCA that is possessed. It will turn on and
> then at random intervals will shut down and power back up. I have
> touched up any solder connections that looked cold. I removed all of the
> tact switches from the front panel control, problem still exists. I
> disconnected the front panel after the set was powered on and still get
> shutdown/startup. the set does not stay on long enough to develop raster
> but does have the HV static on the screen. I am thinking it is the power
> IC but do not have a print. Any and
> all help is greatly appreciated.
>
> thanks, Gary

There's something of a tradition in the repair trade of routinely replacing
all the (physically) smaller electrolytics in the PSU when there is random
triggering of protection circuits.

If you don't have an ESR meter, start by visually inspecting the larger
elecrolytics to see if the top has bulged or the shrink on label has started
to shrivel.

Sometimes a failing electrolytic will run noticeably hot, but be aware that
the aluminium can may not be isolated when you stick your finger on it to
sense temperature.

Alternatively, place a flake of candle wax on top of the capacitor, if it
melts the cap likely has a high ESR and the internal losses are producing
heat - if it gets hot enough to melt hot melt glue, put your safety glasses
on it may be about to explode.


 | 
Pages: 1
Prev: RCA 36V430T Chassis ITC008HYN turns on and off repeatedly.
Next: TV's EHT wants to jump