Philips 42PFL7662D 05 - Backlight Issue.

[Turnip]

Hi Folks,

Have one using inverters 6632L-0470A & 6632L-0471A (Master and slave) where backlight doesn't fire up although the Blue Led on master initially lights up then fades out.

Both board fuses are OK with 24v present, and neither drive chip nor any Fets are shot - Changed the master drive chip even though not popped.

Sound is present using Scart input. Had a feeling that even if the tubes were shot there would be an initial flash, but there isn't, and no indication of backlight voltage with a neon or digital meter near the backlight transformers.

Any thoughts ? - Thanks - Chris.

[jordan]

Replace BD9897

[Ere]

Replace BD9897
 or

from my experience put forward include the LED on pin 17 BD9897 and body, which
immediately shut off protection. The unit earned run successfully completed and handed over.

[Turnip]

Thanks Jordan and Ere,

Replaced the BD9897 even after noting the Fets weren't duff, though suspected was on a looser.

Some folks suppose that duff tubes might be the issue - Guess Ere's 'delete protection' biz could be the biz if I could understand it.

What to do on pin 17 ? - Not at all sure - Chris.

[Ere]

Hi
find a simple LED, and solder its anode to pin 17 of the inverter ic and the other leg(cathode) to gnd, this will shutdown the protection and force work the inverter, even if there's a failed ccfl or other pb..

[jordan]

Blocked protect

[Turnip]

Hi, and thanks Ere and Jordan,

Thanks, attach a picture.

Wasn't sure of the on/off & brightness feeds from the power board as it doesn't feature in set manual, so will try attach - X404 connector seems the biz - Chris.