need help to test inverter transformer

[woaimi]

Re: need help to test inverter transformer

I soldered the 2 new transformers into place, mounted everything, plug in power cable and see no life at all. what is the next thing to check?

[selldoor]

Re: need help to test inverter transformer

I asked what resistance you got and if the lamps flashed as there may be a problem with the wiring. If it is shorted - and you did say there was continuity you could possibly damage the replacement transformers.
They should of course shut down pretty quick but best to check.

[woaimi]

Re: need help to test inverter transformer

selldoor & budm: I thought I saw some resistance indicated when probing the light bulbs connectors. I can definitely be wrong since this is my 1st touch to an LCD journey. Thanks for pointing it out. I'm learning.
RON_CET: I will try your suggestion tonight and will have either a "hooray" moment or more question tomorrow.

[RON_CET]

Re: need help to test inverter transformer

for now replacement of the 2 defective inverter transformers is a start which hopefully will get you up and running provided if there not in damages to the drive area of the inverter but what your seeing is the most common failure with inverter transformers.

[budm]

Re: need help to test inverter transformer

"I checked the light bulbs with ohm's meter and there's continuity"
I am not sure what you are reding, the CCFL should read open circuit, it is just vacuum tube with electrodes at each end.

[selldoor]

Re: need help to test inverter transformer

I am pretty sure you cant test ccfls with a ohms meter. - What did they measure?
Were they all the same? When you tried to switch the set on did they all flash.

[woaimi]

Re: need help to test inverter transformer

Thanks RON_CET,
I had both the 1st (with burnt mark on board) and the 3rd with holes on top) removed and re-measured again just out of curiosity, they still read the same values as the 2nd (still mounted on board). I guess whatever happened the coils must have been undamaged and that's not necessary mean the transformers are still good right? So,, I'm gonna replace that 2 obvious for now to see if that fixes the problem otherwise I will replace out the 2nd as well. Could it be something else that causes the problem to begin with? from visually inspected, I see no blown caps on either this inverter board or power supply board. I checked the light bulbs with ohm's meter and there's continuity. The transformers are the only obvious suspect for now. Any idea?

[RON_CET]

Re: need help to test inverter transformer

I would remove all 3 inverter transformers off board to test,but the one you have mention with burnt marks underneath the transformer is bad more likely busted open from underside and need replacement,the 3rd one you mentioned with the crack and holes also is bad.So it sounds like you have two bad inverters and possible the third is ok provided the primary and secondary is reading correct resistance off the board

[woaimi]

Good day guys,
I have a Westinghouse model SK-32H540S, the one that most known for it bad inverter transformer 4302HXXXXX. Mine too, having that same problem the thing is there are 3 transformers on the inverter board 2 of them look clean although 1 of those clean looking has a burn mark on the board underneath the device, the 3rd one looks like busted with needle holes on top, cracked mark on a side and the melted stuff deposited outside. I used multimeter to test resistance as directed on LCDparts.net and found all 3 of them read the same values as of 1.8K between the Secondaries and 3 ohm between the primaries. My question is which one is the bad one? or is there another way to test these transformers? your suggestion is much appreciated.

-woaimi