Sony TV blows fuses

[[email protected]]

I have a Sony Trinitron from 1989, model KV-20TS10. The main fuse was
blown, so I put in another and plugged it in. Within a few seconds I
heard the power relay click (it turned itself on) and the fuse blew
immediately. Not enough time for audio, picture, nothing. I did a
quick check of the H.O.T. in-circuit and it didn't seem to be
shorted. The bridge rectifier appears to be fine. I'm no TV repair
expert, but it seems this one should be relatively easy, if I had a
schematic.
Are there any common problems with this set that causes this symptom?

 

[Sofie]

hondgm:
Wow.... a little optomistic with your following statement....
"I'm no TV repair expert, but it seems this one should be relatively easy,
if I had a schematic."

Take the hot OUT of circuit and test it to make certain it is not
shorted.... your statement "it didn't seem to be shorted" does not inspire a
lot of confiedence. Be aware that the HOT can fail and not neccessarily
show a direct short on your meter... it can have fatal CE leakage that won't
show up as a short.
...... and check the bridge, you should know for certain that it is good and
not that it "appears to be fine."
Check the B+ voltage regulator and/or replace it and also for shorted/leaky
filter caps in the the raw B+ and the regulation circuitry. Also check for
shorted caps and faulty diodes in the flyback derived B+ circuitry.... all
of this is relatively easy to find without a schematic.
Daniel Sofie
- - - - - - - - - - -- -

 

[Dani]

The fuse rarely blows on those Sony T.V.'s, even when they blow up.
Unhook the degaussing coil, just in case it is drawing
too much current at turn on, but first check the two 2SC4834 switching
regulators.Q601/Q602 (P/N# 872901951), R607 0.1 ohm fusible, (P/N#
120293361), VDR601 (P/N# 180728811), VDR602,VDR603 (P/N# 181005311).
Dani.

 

[[email protected]]

The fuse rarely blows on those Sony T.V.'s, even when they blow up.
Unhook the degaussing coil, just in case it is drawing
too much current at turn on, but first check the two 2SC4834 switching
regulators.Q601/Q602 (P/N# 872901951), R607 0.1 ohm fusible, (P/N#
120293361), VDR601 (P/N# 180728811), VDR602,VDR603 (P/N# 181005311).
Dani.

Are you sure you're looking at the correct set? On this one, I don't
see a Q602, R607, or any VDRs, and Q601 is a little TO-92 package.

 

[b]

I have a Sony Trinitron from 1989, model KV-20TS10. The main fuse was
blown, so I put in another and plugged it in. Within a few seconds I
heard the power relay click (it turned itself on) and the fuse blew
immediately. Not enough time for audio, picture, nothing. I did a
quick check of the H.O.T. in-circuit and it didn't seem to be
shorted. The bridge rectifier appears to be fine. I'm no TV repair
expert, but it seems this one should be relatively easy, if I had a
schematic.
Are there any common problems with this set that causes this symptom?

start by checking the degauss circuit. unplug the coil and see if that
helps.

-B