Dead Sony KV-T25SZ8 TV

S

Sylvia Else

Guest
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.
 
On 12/03/2011 9:18 PM, Sylvia Else wrote:
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.
Click to expand...
I'm not expert but ...

Arcing within the PSU?

Examine it really closely and if nothing is obvious it might be worth
powering up on your bench with the covers off and the lights turned way
down - but you shouldn't completely discount the possibility of internal
arcing in a cap or the transformer.

But I will bow to anyone else with experience.

Make sure you have a small, tightly focused torch, earth leakage
protection, and don't get yourself electrocuted (keep one hand in your
pocket, no loose hair, chains, cloths or anything else, don't touch etc).

If it were me I would balance the cost of a new TV - some of the flat
screens are sold at ridiculous prices v. the time, effort and cost of
repair including the possibility of spending time and effort to discover
you can't get a part - especially if you don't already have good
connections for TV parts
 
"Sylvia Else" <sylvia@not.here.invalid> wrote
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.
Click to expand...

answer is; probably HOT
(probably BU or 2SC)

solder it out and check pins for zero ohms....it shouldnt be zero in any way
of measuring
to locate it, its right beside the HV coil on some heatsink ...beside it is
usually some elco 100 - 470uF / 160 or 250V..solder it out too and check the
cap and ESR as well....so as the diode nearby


repair will cost you max 5$
 
On Sat, 12 Mar 2011 22:18:42 +1100, Sylvia Else
<sylvia@not.here.invalid> put finger to keyboard and composed:

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.
Click to expand...
There appears to be a short on one of the SMPS outputs.

Service Manual for Sony BG-1S Chassis:
http://www.eserviceinfo.com/download.php?fileid=12231

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
 
On 13/03/2011 11:54 AM, Franc Zabkar wrote:
On Sat, 12 Mar 2011 22:18:42 +1100, Sylvia Else
sylvia@not.here.invalid> put finger to keyboard and composed:

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.

There appears to be a short on one of the SMPS outputs.

Service Manual for Sony BG-1S Chassis:
http://www.eserviceinfo.com/download.php?fileid=12231

- Franc Zabkar
Click to expand...
Thanks for the reference.

The horizontal deflection output transistor measures 5.7 omhs from
emitter to base in either direction. It would certainly show as a short
on the SMPS output.

I can source a replacement for $15 (possibly!), but is it the cause, or
just a symptom?

Time for a new TV, I think, as suggested by by David.

Damnation - now I have to choose one - I hate doing that.

Sylvia
 
"Sylvia Else"


** Hey dumbass.

You misspelled "sci.electronics.repair".



.... Phil
 
On 13/03/2011 4:12 PM, Phil Allison wrote:
"Sylvia Else"


** Hey dumbass.

You misspelled "sci.electronics.repair".
Click to expand...
So I did. Now why didn't the server complain?

Sylvia.
 
"Phil Allison" <phil_a@tpg.com.au> wrote
** Hey dumbass.
Click to expand...
was that really nesecarry?!?!?
you really enjoy it, dont you :p

show some attitude at least toward ladies FFS :)))
 
"Gagi-9a6aag"
"Phil Allison"
** Hey dumbass.

was that really nesecarry?!?!?
you really enjoy it, dont you :p
show some attitude at least toward ladies FFS :)))
Click to expand...
** You are new here and know nothing of the past.

Sylvia is no lady.


..... Phil
 
On 12/03/2011 10:18 PM, Sylvia Else wrote:
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.
Click to expand...
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.
 
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