low back lights

[Geoff S]

Hi guys it's been a while!

I've got a videocon VU326LD in for repair with low backlights. They're so low that no picture can be seen. The guy tells me he replaced the inverter.
Supply to the inverter seems ok at 24v plus a 4.8v. Sound is ok.

I can't locate any service info. The inverter is a SSI320_4UA01. The display is LTA320AP02 (Samsung)

I'm racking my brains here because I've seen similar before but cannot recall what the problem was.

Any ideas would be welcomed with a cheer and much happiness.

Geoff

[Turnip]

Hi Geoff,

Naturally suspect that replaced inverter panel, as when screen tubes are duff you usually get a flash at least, often Pink-ish with small screen sizes.

As you have no picture, suspect inverter is duff

Gather replacement inverter has 24V and perhaps the inverter turn on voltage, suggest you check inverter fuses.

Can't guarantee much cheer but all the best - Chris.

[Geoff S]

Thanks Chris

Yep checked 24v plus fuses. I also suspect the "new" inverter.

It's a pain in the whatsit when the customer has been inside but he hasn't boobed anywhere that I can see.

Actually I ran the set with a signal via scart and there's no sound but a purr from the speakers which now makes me wonder if it's a problem with the main board. Perhaps eeprom but it does respond to remote on/off.

Cheers for your reply
Geoff

[Davy]

Have you no spare lamps you could hard wire in just to try? This would confirm the direction of travel, also don't forget the PWM ramp for the brightness control.... just an idea for you.

Shouldn't there be 'Lamp ON' voltage around 3V as well as the 24 and 5V DC?

Dave

[Turnip]

Guess Davy is cool, But preferably on another planet - Chris.