RCA 42LA45RQ no backlights, bodged cap replacement on PSU

[kevinm34232]

Re: RCA 42LA45RQ no backlights, bodged cap replacement on PSU

So were the high voltage caps good on the inverter board, and it was just a PSU issue?

[johnboy1313]

Re: RCA 42LA45RQ no backlights, bodged cap replacement on PSU

I can only assume the caps were good. I did use one on another power supply and it worked. I have no idea what was actually wrong with the PSU.

[donnyb]

Re: RCA 42LA45RQ no backlights, bodged cap replacement on PSU

I can't seem to make a thread so I'll post this here:

I have a RCA RLED-4275a, the back-light comes on once when the tv is turned on, for a split second. then turns off.

I have used this forum to replace capacitors on a few Computer Monitors before with good success.

I have replaced the capacitors which were visibly damaged and I am still getting the same error.

I am getting sound when plugged into a tv source, and when using a flashlight I can see the image is working fine as well.

I have a few pictures of the boards:

[radarguy]

Re: RCA 42LA45RQ no backlights, bodged cap replacement on PSU

Greetings All,

I have the same RCA 42LA45RQ but my inverter board is some what different. I also have a back light issue. I have tried to detect high voltage with a high voltage probe which is giving me a zero reading. I have tried a second board that was supposed to be good and I get the same results. I have sound and the receiver is working. I am wondering if there is a separate trigger signal for the high voltage separate from the receiver processor board. Anyone know?

Here is a slightly blurry picture of my board.

[masessum]

Re: RCA 42LA45RQ no backlights, bodged cap replacement on PSU

I've discovered that one of the transformers is what destroys the 15pF caps. The set may work again for a while, until the new cap fails again, or the transformer gets worse, then the backlight will either be very dim, or simply shut down. You should notice the failed transformer running very hot.