Repair Q on a Sony 27" chassis..

[Vector Viper]

I am working on 2 Sony KV-27TS29 TV chassis, from 1993.

both came in with the typical symtom for these sets; bad regs (C4834) the
black VDR,
and blown hor output (C4927) too, started by a bad connection.

Usually, replacing these parts and soldering does the trick, not with these
2....
Both sets run the Hor out too hard/hot, killing it in no more than 5-10
mins.
The picture looks perfectly normal during this short run time.
If you go into set-up and turn the width down, there is a slight
compression/fold on the right side,
I have seen this before in other sets (Mitsubishi) it always means the
output runs hot when this
is seen. (It's overstressed, not turning off fast enough?)

Has anyone seen a fix for this? I suspect hor drive transformer, yoke or
flyback, in that order...

Also, does the manufacturer of a particular C4927 hor out have better specs
than others?
I have heard of cheaper rip-offs that just do not work...
Should I buy this part from Sony only?

Thanks for helping,
Aaron H.

 

[Shoreline Electronics]

If you use a sub par 2SC4927 , this is what happens.

If you are a servicer with a resale # , Call Universal Semiconductor for a
good quality part. 1-800-222-2321


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


"Vector Viper" <ahowald@w-link.net> wrote in message
news:vpsamna45sh768@corp.supernews.com...

I am working on 2 Sony KV-27TS29 TV chassis, from 1993.

both came in with the typical symtom for these sets; bad regs (C4834) the
black VDR,
and blown hor output (C4927) too, started by a bad connection.

Usually, replacing these parts and soldering does the trick, not with
these
2....
Both sets run the Hor out too hard/hot, killing it in no more than 5-10
mins.
The picture looks perfectly normal during this short run time.
If you go into set-up and turn the width down, there is a slight
compression/fold on the right side,
I have seen this before in other sets (Mitsubishi) it always means the
output runs hot when this
is seen. (It's overstressed, not turning off fast enough?)

Has anyone seen a fix for this? I suspect hor drive transformer, yoke or
flyback, in that order...

Also, does the manufacturer of a particular C4927 hor out have better
specs
than others?
I have heard of cheaper rip-offs that just do not work...
Should I buy this part from Sony only?

Thanks for helping,
Aaron H.

 

[Vector Viper]

"Shoreline Electronics" <jstielau@snet.net> wrote in message
news:eNtnb.15119$oi2.10577@newssvr33.news.prodigy.com...

If you use a sub par 2SC4927 , this is what happens.

That is INSANE! a part of a certain number should be the all the same,
regardless
of who makes them...why oh why are there sub par parts....they are cheaper,
of course...

Thanks for the tip-I ordered the "official" Sony version(part of a kit)
today-we shall see...

Viper

If you are a servicer with a resale # , Call Universal Semiconductor for a
good quality part. 1-800-222-2321


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

Also Firesign theatre!!!

 

[Roy J. Tellason]

Vector Viper wrote:

If you use a sub par 2SC4927 , this is what happens.

That is INSANE! a part of a certain number should be the all the same,
regardless of who makes them...why oh why are there sub par parts....they
are cheaper, of course...

I remember way too many instances where this sort of thing happened. Crown
audio amps for one example used to spec _only_ Motorola brand 2N3055 output
transistors, anything else would void the warranty! And then there's all
those mfrs who specify that their part is a given part number, but
"selected"... SELECTED FOR WHAT? Altec was a great one for this, just
about every single semiconductor in much of their stuff that I got service
info on was labeled like that.

Why do they have to design stuff like this? Grrr....