Dead Sony KV-T25SZ8 TV

[Phil Allison]

"Clifford Heath"

You mean you have no access to ABSE? Spend $US3.95 at www.teranews.com and
get free lifetime access to all the binary groups, limited to 50MB/day.

** Not worth a hoot to me for posting schems or pics unless everyone has the
same.



...... Phil

 

[Phil Allison]

"Stroonz is a Shithead "

"Phil Allison"


******Bollocks.

Most horiz output internal resistors are between 25 and 50 ohms.

** I have seen them with 20 ohms and less.

You need to get out more.

Besides, 20 ohms isn't 5.7ohms.

** The OP corrected her error in the next post - which you have not
bothered to even read.

The 5.7 ohms was measured from C to B.

No clue was given about the use of in or out of circuit testing.

In circuit, E to B reads an ohm or
under as the secondary of the horiz driver transformer is directly
across it..

** Not all HOT drive circuits are like that.

**** More likely a stupid answer.

** Why don't you go and get fucked ?


....... Phil

 

[Phil Allison]

"Stroonz is a SHITHEAD "

Most horiz output internal resistors are between 25 and 50 ohms.

** I have seen them with 20 ohms and less.

You need to get out more.

Besides, 20 ohms isn't 5.7ohms.

** The OP corrected her error in the next post - which like a total
shithead you have not bothered to even read.

The 5.7 ohms was actually measured from C to B.

And the bitch gave no clue about the use of in or out of circuit testing.

In circuit, E to B reads an ohm or
under as the secondary of the horiz driver transformer is directly
across it..

** Not all HOT drive circuits are like that.

Many have a low value R in series with the base with a diode across it.


** Why don't you go **** a dead donkey ?



....... Phil

 

[Phil Allison]

"Stroonz is a PSYCHOTIC SHITHEAD "

Most horiz output internal resistors are between 25 and 50 ohms.

** I have seen them with 20 ohms and less.

You need to get out of that asylum more.

Besides, 20 ohms isn't 5.7ohms.

** The OP corrected her error in the next post - which like a total
shithead you have not bothered to even read.

The 5.7 ohms was actually measured from C to B.

And the mad bitch gave no clue about the use of in or out of circuit
testing.

In circuit, E to B reads an ohm or
under as the secondary of the horiz driver transformer is directly
across it..

** Not all HOT drive circuits are like that.

Many have a low value R in series with the base with a diode across it.

The original exchange was:

" > The horizontal deflection output transistor measures 5.7 omhs from

emitter to base in either direction.

** Probably normal. "

See - no reference is made to any particular set in my remark .


** Why don't you go **** two dead donkeys ?



....... Phil

 

[Phil Allison]

"Stroonz is a LYING PSYCHOPATH "

You said a 5.7 ohm reading was "probably normal" for her Sony.

** Wrong.

The original exchange was:

" > The horizontal deflection output transistor measures 5.7 omhs from

** Probably normal. "

See - no reference is made to any particular set in my remark .

** Why don't you go **** two dead donkeys ?

 

[Sylvia Else]

Sony tvs are notorious for being picky about spares. I dislike them
for that reason, as they usually get repair estimates rejected due to
cost grounds.And that's assuming spares availability...

I recently dumped a 25" CRT set (FE2 chassis I think) - shorted
horizontal output stage. Common fault with the chassis - the
transformer fails, killing the line o/p transistor and damages the
micro. Unless you replace the lot in one go, with genuine sony bits,
you're back to square one... plus the uPc is NLA and an awkward smd
type. Set was BER, a shame considering it was barely 8 years old.
-B

That's the kind of scenario that's deterred me from replacing the
transistor. Your comment about the damage to the microprocessor is
particularly relevant given my inability to persuade the set to produce
sound with the transistor removed, or even to enter/leave standby mode.

Sylvia.

 

[Sylvia Else]

Not familiar with the set so I don't know exactly - but functions
related to sound may
be powered from a rail generated from the EHT transformer.

Even if not, it is possible that it may be muted or disabled by the
CPU if the EHT circuit isn't working correctly.

Or just to make the damned thing difficult to diagnose, thus increasing
the chance it'll be tossed and a new one bought.

Many other functions may be shut off for safety also.

In the past I have found that the majority of sets/monitors (note -
have not worked on many newer than the 1990's)
will work once the H out transistor is replaced, however this isn't
always the case. The tuning caps (usually across the transistor) can
fail or lose capacitance causing the voltage to go through the roof
(they often look normal),
yokes can burn out (Samsung, usually inside on the H section where you
can't see it without removing from tube, usually from corrosion), the
EHT transformer can short internally, or can develop an arc through
the plastic casing to chassis.

Arcing from out of the housing on some transformers that contains the
focus and screen pots. I have seen often

Some of these arcs can be particularly bad, in fact some seem to
manage to burn their way through silicon sealant and continue the arc
as before. (note -too close to the frame to allow a decent thickness)

In some cases, the only way I could stop this was to remove the
aluminium frame from around the transformer, and cut away a section of
it near the where the arc was so as to give the transformer nothing to
arc to. It also allowed more clearance for a thicker coat of silcone
sealant to prevent future problems.



I am leaving out things like dry joints and obviously damaged
components as I assume most people on this group would look for these
before posting.

At one point, I saw some of the smoke escape, but unfortunately was on
the wrong side of the set to see where it came from

Sylvia.

 

[Sylvia Else]

One big thing that would bother me, is paying for and replacing the
transistor, and then finding the problem still there or other faults.
You could change the CPU and god knows what else in between and still
have a problem.

And indeed discover that the still existing fault destroys them again.

TO make matters
worse, it looked as though the FET was designed to put a dead short
across the batteries under some circumstance.

No fuse protecting the battery? Sounds like a serious safety issue -
shorting out lead-acid batteries would have to be good way of starting
fires.

Sylvia.

 

[Sylvia Else]

The thing that probably killed it was that I was using it to charge up
about 5 SLA batteries, one after the other, and it might not have been
designed to be charging for this length of time continuously. once the
5th battery was connected - smoke time.

Still, I'd have expected it to have reached thermal equilibrium long
before even the first battery was fully charged. It shouldn't get any
hotter from subsequent chargings.

Sylvia.

 

[William Sommerwerck]

The set's inability to show any signs of working circuits, with

the HOT removed (or failed), is normal for most TVs made
within about the last 25 years.

Other than a Standby voltage supply, most TVs won't operate
(even partially) without a functioning horiz scan/sweep circuit,
as in general, several voltage supplies are derived from the IHVT
integrated high voltage transformer (some refer to as flyback or
other terms).

My Sony KV-1920, purchased ca. 1974, was one of the first TVs with a
switching power supply. When the supply failed in the early 80s, a guy from
Sony warned me not to try to fix it myself. "If you don't catch all the bad
parts the first time, some of the replacement parts might fail. It's best to
have a trained tech look at it." It cost me around $75 (which seemed a lot,
then) but the set was properly repaired and worked another 15 years.

 

[Meat Plow]

******** Yes, but those are called shorted.




******** She didn't ask about all HOT drive circuits, she asked about
HERS.




Now is that nice?

You can safely ignore Phil's posts. Most do because of his extreme mood
swings and personality disorder.

 

[Phil Allison]

"Stroonz is a **** "


I suspect he's a typical internet bully ..


** Hey - pal.

Blind Freddy can see that YOU are bullying me.

Cos you are a psychotic control freak.



..... Phil

 

[Sylvia Else]

You are probably right, but this was the only change to "normal" usage
I can think of before it failed

Coincidence - there's probably a yet to be discovered perverse law of
nature that says that a machine is most likely to fail shortly after a
totally irrelevant change in the way it is used.

Sylvia.

 

[Sylvia Else]

The set's inability to show any signs of working circuits, with the HOT
(transistor) removed (or failed), is normal for most TVs made within
about the last 25 years.

Other than a Standby voltage supply, most TVs won't operate (even
partially) without a functioning horiz scan/sweep circuit, as in
general, several voltage supplies are derived from the IHVT integrated
high voltage transformer (some refer to as flyback or other terms).

Well, that's possible, though as I've indicated, my TV wouldn't even
enter standby mode.

I suppose it's conceivable that since it failed in operation, it always
tries to power up in that mode, and that the processor won't allow entry
to standby mode unless everything's working. That would seem a bit
perverse, but who knows?

Sylvia.

 

[William Sommerwerck]

Coincidence - there's probably a yet to be discovered

perverse law of nature that says that a machine is most
likely to fail shortly after a totally irrelevant change in the
way it is used.

Here's another one... "A machine is most likely to irreversibly fail shortly
after you've gone to a great deal of trouble to fix it."

 

[Swanny]

This TV died abruptly, and completely without warning, while it was
turned on. It appears completely dead, other than than that the
degaussing still works.

There was some burning smell evident immediately after it failed, but
nothing has obviously suffered heat trauma.

Presumably there's a problem with the power supply, which looks like a
switch-mode. One thing I've noticed is that when power is connected, it
emits a clicking noise - about three times a second. When the power is
disconnected, the clicking doesn't stop immediately but continues for
several seconds, slowing down.

The clicking noise isn't coming from the speakers. I assume it's coming
from a transformer or choke.

Ring any bells?

Sylvia.

In the dark old days (mid 70's) we would find that in Sydney during the
months of December to March the high temp and humidity would cause
triplers to fail (mostly with dust all over them) which would take out
the HOT and sometimes the PSU. Consequently there were a number of
brands of TV's that we would stock up on these parts in October ready
for the rush. I'm not suggesting that this is your fault, however it
does seem familiar.

 

[William Sommerwerck]

In sets that develop a fault, and also have some other

components that have changed values due to age, the
chassis essentially has compound faults, which were
commonly referred to as Tough Dogs, among other names.

The term probably dates back to at least the 30s. It refers to a problem
that refuses to yield to common-sense analysis or trouble-shooting.

 

[Meat Plow]

On a hunch, I checked the garbage AOL email addy that I use to register
for public forums, and there (amongst the ton of spam emails) were more
than a couple of emails offering the same advice. But I'm not
completely convinced he has mood swings or a personality disorder; I
suspect he's a typical internet bully who can only demonstrate bravery
from behind the security of a keyboard. If someone were to act like
that in real life, you go up to them, grab them by the throat, and watch
them fill their Pampers. Still, I've often gotten a good laugh from his
posts.

I've had dialog with Phil that was very helpful and he's even apologized
to me (in his own way) once. On other occasions he's tore into me for no
reason whatsoever. And it's not just me but others that don't do things
the Phil Allison Way. I have no official proof but this behavior smacks
of a sever mental disorder.

 

[bz]

Here's another one... "A machine is most likely to irreversibly fail
shortly after you've gone to a great deal of trouble to fix it."

It is called "the innate perversity of inanimate matter".
There was an article on it published MANY years ago in CQ magzine.

It have some ways to use ipoim to do things around the ham shack.
1) in order to prevent stretching from detuning your antenna, cut the wire
short to allow for stretch.
2) to fix a complex electronic device:
a) go through the parts list and contact all the parts suppliers. You
will find one or two parts that can not be found anywhere; it is one of
those.
b) examine the layout and locate the part that is most difficult to
remove and replace. You just found your defective component.

I don't remember the rest of the article but it has proven to be quite
useful to me, over the years.

73 de N5bz