RCL3210 backlight ON OFF

[paulstef]

Seems to be a common problem, backlight goes on and off randomly.

Main question: I have about 3A on the 24V to the inverter and 550mA towards the T-Con (12V from the same power supply)

Is 3A at 24V a reasonable current for the backlight?

Here is what I checked so far:

1. All electrolytic caps and resonant cap on PSU ok.
2. Controller L6599D ok (swapped it)
3. there seems to be no overcurrent condition according to datasheet. It behaves like it, but couldn't measure overcurrent on ISENS pin. If I remove either t-con or inverter the PSU remains on, as I said it looks like overcurrent detection
4. all readings on the output of the high voltage transformers on the inverter read the same thing, about 1kOhm
5. Heating and cooling doesn't really have an influence
6. It is really the 12V and 24V power supply part that turns off, main 360VDC are ok, 5V are ok, PS_ON signal towards inverter and PSU are ok.

[ReeceyBurger123]

Re: RCL3210 backlight ON OFF

What does the Pson signal do when it faults out ?

[paulstef]

Re: RCL3210 backlight ON OFF

What does the Pson signal do when it faults out ?

Stays on.

[paulstef]

Re: RCL3210 backlight ON OFF

L6599D on the PSU detects overcurrent, reason unknown. I decreased the coupling cap C36 from 100pF to 50pF, (could be removed too). Problem solved.

[CapLeaker]

Re: RCL3210 backlight ON OFF

I had something similar happening here and fixed mine:
https://www.badcaps.net/forum/showthread.php?t=49468

[paulstef]

Re: RCL3210 backlight ON OFF

I had something similar happening here and fixed mine:
https://www.badcaps.net/forum/showthread.php?t=49468

All the outputs of the transformers showed pretty much the same value, 1kOhm.
I didn't want to spend money trying another inverter board..

Would be nice if one day someone could measure the current towards to inverter board so we have something to compare.

[CapLeaker]

Re: RCL3210 backlight ON OFF

I don't have that TV anymore here to take measurements, but I do still have the old inverter board. The transformers have to be within 3% of each other. My outputs measures 860 to 870 Ohm for a good one and the bad transformer measures 953Ohms.
New inverter board is 11 bucks... so not much lost. Look at the part number I noted down in my thread.

[paulstef]

Re: RCL3210 backlight ON OFF

I don't have that TV anymore here to take measurements, but I do still have the old inverter board. The transformers have to be within 3% of each other. My outputs measures 860 to 870 Ohm for a good one and the bad transformer measures 953Ohms.
New inverter board is 11 bucks... so not much lost. Look at the part number I noted down in my thread.

Hum, my transformers were all within 3% and had all around 1k. Maybe they don't use the exact same transfomers in all TVs. Around here (Canada) everything is expensive, then on eBay you pay shipping fees etc... Didn't think it was worth it for what the guy wanted to pay...