Help! with Panasonic TV.

[Les McCready]

Hi.
I hope someone has had experience with Panasonic CT31XF43CU.

I started to loose the top part of the picture with the horizontal lines
folded over, then the vertical quit and I had a horizontal line for a moment
before the set died.
There does not seem to be any DC load condition on the horizontal 144V or
vertical 27V power sources.
There must be an AC circuit failure because it is shutting down the power
supply if I unplug the set and plug it back in it will try to restart I get
a burst of noise from the audio section and it powers down again and will
not restart.
I have checked the protection transistors and they are ok.
Has anyone seen this before and could possibly suggest how to test the
vertical section.
The capacitors in the vertical section test ok for ESR.
How can I test the LA7845 vertical output chip??

Thanks in advance for your help.

P.S sorry to repost this but I had no response the first time.






-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

 

[Sofie]

Les McCready:
???? "protection" transistors?..... what exact transistors did you test?
Which ESR meter did you use to test the capacitors in the vertical
deflection circuitry..... did you also ESR check the capacitors in the SMPS?
Did you check the HOT and any of the low-ohm power resistors in the B+
distribution and the flyback derived B+ feeds and look for dry/cracked
solder connections? Also did you check the SMPS Regulation, flyback derived
B+ and the standby B+?
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


snipped:

"Les McCready" <lmccready@igs.net> wrote in message
I hope someone has had experience with Panasonic CT31XF43CU.
I started to loose the top part of the picture with the horizontal lines
folded over, then the vertical quit and I had a horizontal line for a
moment
before the set died.
There does not seem to be any DC load condition on the horizontal 144V or
vertical 27V power sources.
There must be an AC circuit failure because it is shutting down the power
supply if I unplug the set and plug it back in it will try to restart I
get
a burst of noise from the audio section and it powers down again and will
not restart.
I have checked the protection transistors and they are ok.
Has anyone seen this before and could possibly suggest how to test the
vertical section.
The capacitors in the vertical section test ok for ESR.
How can I test the LA7845 vertical output chip??

 

[Les McCready]

Hi Daniel
More info.
Q805 and Q451 horz and vert over current protection transistors.
dick smith esr meter.
I removed the Horizontal driver transistor Q501 to allow the smps to come up
and it works ok.
I ring tested the HOT and it is ok.
I checked all solder connections and they are ok.
I have checked a number of the power resistors in this section and they all
tested ok.
Q501, Q753, Q551, D552 are all good.
Thanks in advance for the help.

"Sofie" <sofie@olypen.com> wrote in message
news:voranpa3kbg712@corp.supernews.com...

Les McCready:
???? "protection" transistors?..... what exact transistors did you test?
Which ESR meter did you use to test the capacitors in the vertical
deflection circuitry..... did you also ESR check the capacitors in the
SMPS?
Did you check the HOT and any of the low-ohm power resistors in the B+
distribution and the flyback derived B+ feeds and look for dry/cracked
solder connections? Also did you check the SMPS Regulation, flyback
derived
B+ and the standby B+?
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


snipped:
"Les McCready" <lmccready@igs.net> wrote in message
I hope someone has had experience with Panasonic CT31XF43CU.
I started to loose the top part of the picture with the horizontal lines
folded over, then the vertical quit and I had a horizontal line for a
moment
before the set died.
There does not seem to be any DC load condition on the horizontal 144V
or
vertical 27V power sources.
There must be an AC circuit failure because it is shutting down the
power
supply if I unplug the set and plug it back in it will try to restart I
get
a burst of noise from the audio section and it powers down again and
will
not restart.
I have checked the protection transistors and they are ok.
Has anyone seen this before and could possibly suggest how to test the
vertical section.
The capacitors in the vertical section test ok for ESR.
How can I test the LA7845 vertical output chip??

-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----