Also resolder theconnections of the LOPT, H-Driver Transformer, and Driver
Transistor. Seen way too many of their sets with funky solder conections
around those areas. Loss of drive can cause the output to blow.
"ian field" wrote in message
...

"sigmma" wrote in message
...

Hi I have a Sony KV 29SZ1, (Perth Australia) with a ticking or clicking
noise, no picture and no sound. It looks like at this stage the problem
is in a fuse, my question is how can you tell which one it is, I can
hear the thing ticking away but I just can't locate it (I have removed
the TV cover)...


I have a Sony KV 29SZ1 that has a blown HOT. It is owned by my
apprentice who doesn't have a great deal of cash to throw around, so I
told him to bring it into work and we would have a go at fixing it.

The fault was simple, would not turn on. I opened it up and put the
meter across B+ - 0v. I could also hear it ticking. So the first thing
I did was pull out the HOT and test it, sure enough it was SC. I sent
the the young fella out to buy a new HOT which turned out to be AU$30.

So, the question I ask is: Is there in easy way to tell if the LOPT is
the reason the HOT has failed? I don't really want to put the new part
in if it is going to blow straight away. I was thinking about putting
it in and bringing up the power slowly from a variac. Will this help?

TAI,

AP[/i Wrote:



--
sigmma

Replace the H-transistor, but do not solder the collector terminal - route
this via a 60W bulb which will limit the current if the LOPT has shorted
turns. If this arrangement fails to develop a voltage across the LOPT
primary - don't despair, it could be a S/C rectifier for a scan derived
supply, just follow the tracks away from the LOPT and look for diodes to
test. Another common cause of H-transistor failure is the flybak tuning
capacitor - this is often a disc-ceramic type (normally go S/C and
split/burn!) the regular high voltage wound foil types commonly fail O/C
and allow the peak flyback voltage to exceed the H-transistor's Vceo!

Caution - examine the flyback tuning caps first - the current limiting
lamp won't protect the transistor from excessive flyback if it fires up!!!
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