TV Probs

[Dave]

I'm a electronic tech but have practically zero experience on TV's
(apart from I know they suffer from dry joints and have high voltages
inside!), so would anybody like to diagnose the following fault for
me:

Picture has shrunk (vertically) and gone into like a letterbox format.
TV is a toshiba (UK) Model No. 2505DB

Pictures of the fault can be viewed at:

http://www.beanpix.com/IMG/701016038225691.jpg
http://www.beanpix.com/IMG/701016039232641.jpg

Any hints or tips would be appreciated.

Cheers
Dave.

 

[Art]

Probable problems in the vertical circuit and associated power supplies. ESR
the caps in the circuit.

 

[[email protected]]

common problem with Toshibas, normally a capacitor located near the
vertical IC (often in the range of 2.2 to 10uF). just replace them all
if unsure.

 

[Dave]

Thanks for the help. Now a couple of questions (apart from how did my
message end up under this thread?!) bearing in mind I haven't taken
the back off the TV yet - How will I recognise which is the vertical
IC? I have an ESR meter - will this be any use finding the offending
component? (the cap, not the IC of course!). Do I need to take an
precautions before starting work/applying my soldering iron/expensive
meter to the board?

Cheers
Dave.

 

[b]

SEE THE FAQ and notes on the troubleshooting and repair of tvs
www.repairfaq.org

 

[Gary J. Tait]

Thanks for the help. Now a couple of questions (apart from how did my
message end up under this thread?!) bearing in mind I haven't taken
the back off the TV yet - How will I recognise which is the vertical
IC? I have an ESR meter - will this be any use finding the offending
component? (the cap, not the IC of course!). Do I need to take an
precautions before starting work/applying my soldering iron/expensive
meter to the board?

More or less, it has the appearance of an audio amp of a couple watts.

 

[Franc Zabkar]

common problem with Toshibas, normally a capacitor located near the
vertical IC (often in the range of 2.2 to 10uF). just replace them all
if unsure.

Some Toshibas have a problem cap near the jungle IC that produces
similar symptoms. The vertical collapse fault in my Toshiba TV was
traced to a 2.2uF 50V cap near the TA8718N IC.


- Franc Zabkar

 

[Dave]

Have spent several hours cleaning insides while plucking up courage to
remove HT lead (went OK, am still here!). Have removed PCBs and
checked C372 (2.2uF) with ESR meter - was rather high at 185R!! so
have ordered one as well as IC371 (TA8739P) just to be sure. Will let
you know how it goes when parts arrive. Thanks to everyone for your
help.

Dave

PS
This is a pretty good site for repair tips:
http://fileshare.eshop.bg/repair_tips_database/Toshiba_007.html

 

[Dave]

Got the parts and fixed the fault.
Thanks to everybody who responded.

Dave