Sony KV-35S36 choppers run hot

[Guest]

Hi. Sony KV-35S36, come in DOA. Replaced choppers and .1 ohm res, HOT,
flyback, cleaned H drive transformer, fixed bad solder joints throughout.
Set runs fine, but after a time blows the choppers and .1 ohm res. H drive
transistor checks good. HOT stays fine and runs relatively cool, going by a
feel of heatsink after it dies. The choppers in ps run quite hot, and I'm
trying to figure why. I've not noticed anything like horizontal collapse
since replacing HOT and flyback (with Sony original). Have checked caps on
ps board. Would love to get this heavy beast back where it belongs. I've
killed a few choppers doing run tests and am getting tired of murdering
innocent transistors. It can run some hours before death, so kind of a
surprise when it occurs.

Many thanks for any ideas,

Danny

 

[Arthur Jernberg]

Look in the chopper supply circuit if there are small red or blue caps near
the chopper transformer. I've seen quite a few of those causing problems.

 

[JURB6006]

We've had a few of those that turned out to be the CRT pulling too much
current. Sony tech line says it's not all that uncommon.

Warning, if you decide to test this theory don't run the set with the CRT
socket disconnected, you'll have enough static electricity around to satisfy
Nikolai Tesla. Better to just unplug the wires to the CRT socket board leaving
the grounds. This is because the Hstat/bleeder resistor is inside the CRT. (if
it has one) Even some of them without the control still have it.

BEGIN RANT

They were too damn cheap to put a 15 cent fuse on the regulated B+ line in
these $400-800 sets !!! I got three things that say Sony on them and that
number will never increase. They are not a recommended purchase. I wouldn't hit
a dog in the ass with these pieces of crap !

END RANT

JURB

 

[LASERandDVDfan]

I wouldn't hit

a dog in the ass with these pieces of crap !

For consumer stuff.

But, for professional video. The rants go to Panasonic. - Reinhart

 

[Shoreline Electronics]

Where are you buying your 2SC4834's from?

==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
[email protected]
========================
"If you push something hard enough it will fall over."
Fudd's First Law of Opposition - Sir Sidney Fudd

 

[David]

Are you sure you are using the correct 2sc4834's?
There are in fact TWO series of those according to Sony.
The ones used in the smaller sets will not last in the larger sets.

Did you follow all the standard SMPS waveform analysis checks Sony
recommends for verifying proper operation of that SMPS?

David

 

[Jack]

ESR all caps in power supply.

 

[Jason D.]

For consumer stuff.

But, for professional video. The rants go to Panasonic. - Reinhart

My sound off: AKB! Get that shit a switch either hardware or
software to turn off AKB. A recent Samsung TV (TXM2x56, that one that
plays a melody every time power turned on or off) has it in service
mode and allowed me to turn off and finally see the pix and did a fix
on it w/ no pix in 1 hour from days with previous older samsung
without this switch! :-O

Oh, that new samsung G2 check mode is ultra COOL! too low, text is
blue, green is OK, red too high G2, easy to set properly.

Cheers,

Wizard