Philips 21CE1251/08 repair question

[nibble]

Hi,
After a wait of two years my mother in law finally got me to take a
look to his old philips TV. Obviously no manual and no schematics are
available so I've started an "analysis" on it but with no luck.

Actually the TV has three main problems:
- a sepia horiz. strip on the bottom of the tube.
- bad reception of image
- few or none color image (may be caused by bad reception).

I've tryied redoing some soldering but the TV still present these
problems and I'm a bit short of ideas on what to try next.

Have you any suggestion on possible test I can do on this old TV or is
better to go out to shop a new one to my mother in law?

Best regards
nibble

 

[b]

nibble ha escrito:

Hi,
After a wait of two years my mother in law finally got me to take a
look to his old philips TV. Obviously no manual and no schematics are
available so I've started an "analysis" on it but with no luck.

Actually the TV has three main problems:
- a sepia horiz. strip on the bottom of the tube.
- bad reception of image
- few or none color image (may be caused by bad reception).

I've tryied redoing some soldering but the TV still present these
problems and I'm a bit short of ideas on what to try next.

Have you any suggestion on possible test I can do on this old TV or is
better to go out to shop a new one to my mother in law?

Best regards
nibble

that set has a cp90 chassis.
try resoldering around the chroma chip and the IF section, maybe some
of the coils need a tweak if reception is poor.
Also try with a known good rf signal, say from a video, not the
aerial, to be sure the tv has the problem. does the image look ok thru
the scart connector?

if none of that works search for these sites here, theyall have a lot
of known problems on the cp90.

eservice info
highland electrix
e-repair
hamradio badarc

regards, B.

 

[Skype_man]

Try the 100 uf @ 200 volt capacitor near the flyback,
by the metal plate by the flyback. Sky.

 

[nibble]

Thanks for the reply!

I've found the schematics on the eservice site and I plan to do some
testing this week end.

ciao
Pietro

 

[nibble]

I'll add this to the thinks to try.

I have now some good stuff to check this week end

thanks for the reply

best regards
nibble

 

[nibble]

Thanks everybody for the suggestion and good advise.

I've learned something during this days on the CP90 TV set, but it was
not enought to revive it...

:-(

This is what I've tried:
- I've connected a DVD to the SCART to undertand if the image problem
was due to the receiption or to the control section. With this signal
source, image was clear but with poor colors and now red at all.
- From schematics, I've seen the three BF483 that drives B, R and G
channel and substitued the R driver with a BF422 I have around, but
without any changes.
- I've checked the 100uF@250V near the flyback, and it was ok.
- took of NiCd battery, it loose some acid. No changes.
- Redone welding around chrome chip and on other areas, withou any
changes...

At this point I've decided it was too much for this and gone having a
great lunch with a good wine bottle of Barbera.

Thanks everybody for help and suggestion, I've learned something during
this repair-try, and this was good!

regards
nibble