On 3 sep, 08:53, PeterD wrote:
On Thu, 3 Sep 2009 04:39:23 -0500, "Mark Zacharias"





wrote:
"Alec S." wrote in ....
Hi,

A 19" Sony from 1990 recently blew out. For the past year or so it has
been
flickering a bit, usually clearing up when warmed (I also had a little
success
by fiddling with the power cord, ie getting a better connection by
readjusting
the connector).

The other day while it was on, it began to smell like something was
burning, and
then the TV went off (I think there was a noise too). I cracked 'er open
and
took a look. I found that one of the three cement, fusible power resistors
had
literally blown. The ceramic housing was split down the middle of the
length and
the wire-wound resistor was cracked in half. (Oh, and both of the fuses
that I
could find were fine.)

As luck would have it, I happened to have an identical resistor that I
salvaged
from the circuit board of another TV from a few years ago. Like the dead
one, it
too was a 20W, 150 Ohm cement, so I replaced the dead resistor and hoped
for the
best.

Unfortunately it was only slightly better. Before, the relay would click,
but
nothing else would happen (no LED even). Now, when I plug it in and turn
it on,
the relay clicks, and there is a brief startup hum (but nothing else), and
then
it goes back to click-then-nothing at all (other than the new power
resistor
heating up). If I wait a while each time before turning it on, then it
will do
the brief hum after the relay click.

There is a 560uF, 200V capacitor nearby whose top is fairly bulged.
Unfortunately my DMM doesn't have a capacitance testing function, but I
figure
my next move is to replace the cap.

Any ideas? Thanks.

--
Alec S.
news/alec-synetech/cjb/net

I don't hink the cap is your problem. A bulged or curved plastic cover on
the top of the cap is not a failure.

It's not? Odd, virtually all caps I've run across with buldged cases
were failed.

If it's the metal can that has split at
the top (vented), fine.

And a split case (the extreme, or final stage) is not 'fine'. It is
dead.





We really need a model number to give you any more specific advice.

That said - the resistor you mention is not a typical Sony failure that I am
aware of.

Mark Z.- Ocultar texto de la cita -

- Mostrar texto de la cita -- Ocultar texto de la cita -

- Mostrar texto de la cita -

Normally speaking big electrolytic capacitors such as a 560uF, 200V
has a plastic disc on top of the aluminium cylinder and I
it´s quite frequent for that disc to become bulged, while underneath
the aluminium can is perfectly flat, thus one can´t say that the cap
is damaged just because that plastic disc became bulged. I don´t think
the cap is damaged, and the description of the TV failure points
toward something more serious: a damaged HOT, a shorted switching
transistor, etc.