Polaroid TLX04243B Backlight flashes then out

[102mm]

I picked up this TV with a crazy issue and I can't figure it out. It powers on, the backlight flashes for a second with a screeching noise on the Power supply then goes out and the red LED on the power supply starts flashing. I removed and checked all the caps, including the ones under the heat-sink and they seem to be good. I didn't notice any dark spots on the panel indicating a bad CCFL so I am stumped for now. Any help would be GREATLY appreciated. Pictures below

[ReeceyBurger123]

Re: Polaroid TLX04243B Backlight flashes then out

First thing to try is to heat the Psu with a hair dryer and see if doing that keeps the backlight up. If not will help you further.

[102mm]

Re: Polaroid TLX04243B Backlight flashes then out

First thing to try is to heat the Psu with a hair dryer and see if doing that keeps the backlight up. If not will help you further.

tried that first, no go.

[ReeceyBurger123]

Re: Polaroid TLX04243B Backlight flashes then out

Ok, right do you know how to check the inverter transformers ?

[102mm]

Re: Polaroid TLX04243B Backlight flashes then out

No, but i can learn real quick.. do i need to remove them?

[ReeceyBurger123]

Re: Polaroid TLX04243B Backlight flashes then out

No you can keep them on the board, have you a Dmm ?

[102mm]

Re: Polaroid TLX04243B Backlight flashes then out

yes i pulled them off and tested them with my dmm.. i got 1 ohm on the primary and 13 ohms on the secondary.

[ReeceyBurger123]

Re: Polaroid TLX04243B Backlight flashes then out

Is that for both on the secondary output ?

[102mm]

Re: Polaroid TLX04243B Backlight flashes then out

Yes. it is.

[budm]

Re: Polaroid TLX04243B Backlight flashes then out

https://www.badcaps.net/forum/attach...7&d=1459812008

The 3-leg device on the middle of the board is soldered properly? It looks like it was removed and put back in place with bad soldering works.
Also check the capacitance of those two big brown poly caps by the inverter transformers.
How is the DCV on the main filter cap, about 380~400VDC and steady?

[dick_barton]

Re: Polaroid TLX04243B Backlight flashes then out

https://www.badcaps.net/forum/attach...7&d=1459812008

The 3-leg device on the middle of the board is soldered properly? It looks like it was removed and put back in place with bad soldering works.

Spot on budm. There's no way that is soldered back in place.

[ReeceyBurger123]

Re: Polaroid TLX04243B Backlight flashes then out

He desoldered that to get at the caps though. But it does need to be properly resoldered.

[dick_barton]

Re: Polaroid TLX04243B Backlight flashes then out

There's a few poor solder joints but the image is not well focused so there could be more bad joints

[102mm]

Re: Polaroid TLX04243B Backlight flashes then out

Oh yea, I took the pictures before i soldered the parts back after taking off the heat sinks and replacing the caps. everything is soldered properly that i took off..

SO now i also have a 32" version (FLX-3211B) doing exactly the same thing.. It has a smaller Power supply P/N: IPOS 150. on this one there the red light of the power supply does not flash, it's just a solid red.. exact same symptoms

[dick_barton]

Re: Polaroid TLX04243B Backlight flashes then out

Going back to the Polaroid set, do you have all the dc supplies as given alongside each of the connectors?

[ZnsaneRyder]

Re: Polaroid TLX04243B Backlight flashes then out

Disregard this post, wrong TV

[102mm]

Re: Polaroid TLX04243B Backlight flashes then out

Going back to the Polaroid set, do you have all the dc supplies as given alongside each of the connectors?

All the voltages are present. The TV is working except for the back light.