Toshiba Cinema series 36" Intermittent No Picture

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View


We got a used TV for free (Thank you, FREECYCLE!) and when it works,
it works really well. However it has an intermittent problem of no
picture.

This is a Toshiba Cinema series CN36H95 manufactured 1998, 36" with a
picture tube (CRT?).

The picture intermittently won't work when we power on the television.
We usually can jimmy with it and get it to work. Once the picture is
reliably on, it stays on until we turn off the power.

The sound works fine even when the picture isn't on and the channel
changing works too. I have a VCR and a DVD player hooked up to it and
a rooftop antenna. We don't have cable TV.

The ways we can get the power to come on are by tapping or banging on
the front of the TV at the bottom, near where the connectors and
control buttons are. Also, my husband has had some success with
jamming something rigid (like a screwdriver or metal rod) underneath
the front edge of the TV, about 1/3 from the left of the TV. We leave
it there and usually when we can't get the picture to come on, just
wiggling this will bring the picture up. Sometimes putting something
heavy on TOP of the TV will help.

All these methods make me think that there must be a loose or dirty
connection in the front part of the TV, near the bottom.

My husband did take off the back off the TV and blow some dirt out of
there. It was REALLY dirty. The people before us must have been
smokers, from the looks of things. We also took apart the remote and
cleaned it and it was really yukky with yellow grime.

I think what we need to do is get into the front of this TV somehow
and clean it and make sure all the connections are tight. What we
don't know is how to take off the front, if there even is a way. Once
we have it off, what do we need to check? How should we clean it? What
is there to be careful of?

My husband is generally very handy - can fix just about anything
(furnace, VCR, automobiles, etc...). However, he hasn't had a lot of
experience fixing televisions and I want to make sure the problem
isn't made worse. Even though it's kind of inconvenient, usually we
can get the TV to work with some prodding and jimmying. I'd hate for
it to be ruined, since we cannot afford to get anything else, not even
used.

Any input would be helpful. I have skimmed through the information at
repairfaq.org and found it fascinating. However, I don't know enough
about TV's to discern what will be helpful since I don't see our exact
problem listed. Even some information on which section to read
thoroughly would be appreciated.

Thanks so much!
Lisaquing

Re: Toshiba Cinema series 36" Intermittent No Picture


Quoted text here. Click to load it

I meant PICTURE. "The ways we can get the PICTURE to come on"

Sorry for any confusion.

Lisaquing

Re: Toshiba Cinema series 36" Intermittent No Picture


On Fri, 27 Nov 2009 17:55:08 -0800 (PST), Lisaquing

Quoted text here. Click to load it

You need to remove the board(s) and check the solder side for dry
solder joints. Reflow any bad joints that you find, particularly in
the areas where you see that the board has been discoloured due to
heat. Resolder all the transformers and coils regardless of their
visible condition. Replace the small electrolytic capacitors in the
power supply with low ESR types. Watch out for the high voltage
capacitors -- they may retain significant charge even after you
disconnect the set from the mains. If you need to remove the anode cap
from the CRT, follow the instructions in the FAQ. The CRT can still
bite you, even several hours after you *think* you've completely
discharged it.

Good luck.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Re: Toshiba Cinema series 36" Intermittent No Picture


Quoted text here. Click to load it

Franc means printed circuit boards when he says "boards".

When you say the picture won't turn on, do you mean the screen stays
dark, or does it light up, but just no "picture/video" information on
the screen?  Does the sound come on and off completely normally using
the remote to turn the set on and off?  If the set has a picture tube/
CRT, when you turn on the tv, do the hairs on your/his arm stand up.
If they do, then that is an indication that the high-voltage for the
CRT is turning on correctly.  If there is no high-voltage, then you
have narrowed down the problem to a much smaller portion of the
chassis.

Re: Toshiba Cinema series 36" Intermittent No Picture


Quoted text here. Click to load it
n? A0%

The screen stays dark. Once we "adjust" it (wiggle things around, tap/
bang on the chassis), we can usually get the picture to show up.
Sometimes we get a static-y or snowy picture.

Does the sound come on and off completely normally using the remote to
turn the set on and off?

Yes, the sound works normally using the remote to turn the TV on/off.

 A0%If the set has a picture tube/CRT, when you turn on the tv, do the
hairs on your/his arm stand up. If they do, then that is an indication
that the high-voltage for the
Quoted text here. Click to load it

Yes, the hairs on my arm stand up.

We have not yet attempted the circuit board repairs as described by
Frank. Hopefully sometime this weekend.

Thanks for your help.

Lisa

Site Timeline