Panasonic TX28PS12 (Euro 9L)

[Turnip]

Hi Folks,

Have one of these that cuts to S/by after about 5 seconds. Picture geometry seems OK and aspect variations seem to work (sound too is OK 'till cut)

Only note found was D558 S/C and R578 O/C (Pin 2 LOPT) but these are fine. HT is around 140v until it cuts, and nothing seems to be burning.

Any thoughts  ?  - Chris.

[brainstorm]

Hi Chris,

Have a  look for dry joints around the field op ic, but you can get drys anywhere on these.

 Do you get anything at all on the screen before it goes off?

If its got a philips tube that might be short?

Ive had Field ICs fail in other pana chassis

If you need a circuit let me know

Brian

[Turnip]

Hi Brian, and thanks a lot,

Picture and sound are quite normal with aspect ratio variations (if yer awful quick) doing the job as expected.

Tube is a warranted Panasonic, but have known these to be Philips under the label, but there again, a colour flash/flood, gives the game away.

Got the shematic from site called Quuq - was impressed, as ever - Chris.

[brainstorm]

Hi Chris,

Picture is perfect and no sign of a fault as it trips,
I presume you have monitored the HT rail and its not going high?

I have had sony, philips etc tripping off when G2 incorrect, you could try tweaking it.

Other than that i would try disconnecting protection and see if anything goes bang!

Sorry I can't help more

Brian

[Turnip]

Thanks Brian,

Tried the A1 voltage bit as it's listed somewhere - HT steady at 140v and pic/sound normal when it cuts.

With thoughts of dries in mind resoldered most everything around warmish areas, then thought to see what a touch of heat around P/S would do. Found set stayed on longer, so checked all caps with freezer and heat - inconclusive.

Think to do as you suggest and dis. protection. Should you hear a bang from the East, it's probably not any second coming but   -  Thanks again  - Chris.