Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

[Seville]

Hello all!

Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply .

I have a Westinghouse LED TV, model WD48FAB100 that is not powering on. Upon removing the back cover, I noticed a burn mark where the AC cord connects to the power supply/main board. In this model, there is only one board combining the two functions. Previous owner said the TV experienced a lightening strike, but who knows. I checked the main fuse, tested OK. Here are a collection of readings from the power supply ports. Looking for some guidance on what to test/check next. I'd like to replace the whole board; however, every source is out of stock and none can be found on eBay. Here are the readings:
5V 5.15
Red 3.30
GRN 0.14
IR 5.07
GND 0
K0/S 3.30
K1/C+ 3.30
K2/C- 3.30
K3/V+ 3.29
K4/V- 3.27
K5/M 3.23
K6/P 3.31
K7/N 3.31
GND 0

The LED backlights tested good.
Photo of front and back of board and burn mark. Thank you for your suggestions!

[nomoresonys]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

do you have about 120 volts there? test on the outside of the connector where you plug the power cord in, the metal parts right there by the burn marks.

[Seville]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

Yes, good question, I measured 120v at the at the connector. Also measured the continuity between the connector prong and where it attaches to the board. All checked out.

[nomoresonys]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

did you check those 4 big diodes there?

[Seville]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

Thanks, I need a little help on how to test those. I have a multi meter and need some guidance on how to test. Which end to place the +/- probes and what reading would be considered good, thank you for the guidance!

[nomoresonys]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

put meter in diode mode, test on each leg then switch probes, should get 1, then switch should get a reading other than 1, like .4xx to .7xx or so. those let voltage flow one way. the 1 means no voltage flowing in that direction which is good.

[Seville]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

Thank you, that helps! I'll give it a try later today and report back.

[vinceroger69]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

Thank you, that helps! I'll give it a try later today and report back.

when testing diodes make sure the tv is unplugged (test un powered)

[nomoresonys]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

when testing diodes make sure the tv is unplugged (test un powered)

+10, I forgot to emphasis that, I suggest testing diodes so often, sometimes I forget the warning.

[CapLeaker]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

That yellow x cap is probably toasted.

[Seville]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

Thanks for the tip on testing non powered! I tested each Diode, DB1, DB2, DB3, and DB4 receiving these readings: 613,1; 610,1; 612,1; and 610,1. So they appear ok. I believe these are part number 1N5408.

In testing the yellow rectangle cap board position CXB1 (part number CBB62B) I set my multi meter at 2000k ohms and the readings climb to 1184 and then stop. Not sure if that is good/bad or pass/fail.

Next step to test please!

[R_J]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

By looking at your voltage readings the power supply section is working ok. The burn mark on that yellow cap is the result of someone shorting the a/c input pin (see the arc mark on the copper pin)

On these boards it may be corrupt data in the eeprom.

[nomoresonys]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

makes sense, wouldn't be surprised if the firmware got messed up from the lightning strike.

[Seville]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

Thanks, anyway to correct that or should I recycle this TV?

[lotas]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

f lightning passed through the board from the antenna socket or what was connected via HDMI, then with a probability of 100% the processor and dc-dc converters were damaged.

[nomoresonys]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

it's not common but I have had an old lcd sony that was struck by lightning and only the firmware got borked, firmware replacement fixed it, have seen it a few other times also.

[nomoresonys]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

but more than likely something got fried.

[Seville]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

Thanks all.

I'm thinking the same thing, something was fried. Looking for what to test next to locate and replace the fried component(s).

Any guidance on how to reload firmware and what to test next?

[nomoresonys]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

not sure about update procedure, website is there, tried clicking some things not much success, maybe you have to be signed in to use their site, not sure, might want to check voltages on the driver board/s see if its getting that far: https://westinghouseelectronics.com/support/

[nomoresonys]

Re: Westinghouse TV WD48FAB100 Not Powering On – Burn Mark Found on Power Supply

heres a good tutorial on testing components: https://www.youtube.com/watch?v=ocqnqmBxiqY