Insignia NS-32L430A11 Backlight problems

[kevinm34232]

backlight was shutting off after about 30 seconds of TV turning on. Found T401 was burned. Ordered a kit from shopjimmy, the transformer was slightly different part #, original 8TC00569. Replaced with 8TC00588.

Then R721 and Q701/702 burned up. They were part of the kit, replaced them and they burned again.

Is this transformer not compatible? All other parts are the same in the kit.

[dick_barton]

Re: Insignia NS-32L430A11 Backlight problems

Have you checked that there is not a problem with the wiring from the transformer to the tube shorting to the case which may have been the cause of the original fault and also responsible for the second fault?
Perhaps checking the CCFL connectors resistance.
Have you checked the capacitors C40x

[budm]

Re: Insignia NS-32L430A11 Backlight problems

It can be due to worn out lamps and drawing too much current from the transformer HV winding.
Those little blue ballast caps are OK? No leakage resistance on them?

[kevinm34232]

Re: Insignia NS-32L430A11 Backlight problems

Is it weird that before, with the original transformer, it would stay on for 30+ secs, then shut off, never blowing any other components?

Now it violently burns up the resistor smoke and flames!

[dick_barton]

Re: Insignia NS-32L430A11 Backlight problems

All I can think of is to compare the winding resistances and see if the replacement compares with a good transformer.

[kevinm34232]

Re: Insignia NS-32L430A11 Backlight problems

I got a new power/inverter board which works and now I can see a dark row where it looks like a bulb is out.. Bummer

[dick_barton]

Re: Insignia NS-32L430A11 Backlight problems

That could be because the CCFL tube has slipped out of it's connectors.