need help to test inverter transformer

[Rudy.ALvarez91586]

Re: need help to test inverter transformer

did you ever fix this problem it looks like the the middle on is the only orginal transformer on the board that hasn't been switched yet i had the middle transformer on the inverter board go out I changed out the middle transformer but still i got nothing

[Bigbe]

Re: need help to test inverter transformer

It worked for me too.

[jesselyons2002]

Re: need help to test inverter transformer

Ok replace all three of the inverter on the power inverter board. Just like the guy in this thread did. Tv works perfectly. Thanks to everyone in this thread.

This is the WESTINGHOUSE SK-32H540S

fyi. This is cheaper then buying the power supply board and was easier to get. Just incase anyone else wants to do this.

[jesselyons2002]

Re: need help to test inverter transformer

I am going to try this myself too. I want to see if this fixes my problem too. Since the guy I bought the tv from said he only replace two of the inverters.

[woaimi]

Re: need help to test inverter transformer

glad it helps. cheer!

[justtaint]

Re: need help to test inverter transformer

Thank you for posting all this info. I tried replacing a single transformer more than a year ago and it didn't help. I got tired of looking at it in the corner of my office, so I took another look on the internet for other people experiencing this same issue. This time I bought two replacements and made sure to match the transformers as closely as possible. Fired the set up and *fingers crossed* it's working.

[woaimi]

Re: need help to test inverter transformer

That was what I did and it works .....and still working. It could have been something else that or just a beginner's luck or a miracle.
hope you get the same luck and many thanks to the folks here.

[pk7tanner]

Re: need help to test inverter transformer

Are you shitting me? Wow, I messed with this set (like the rest of you) for ever. I did the same thing (bought two transformers) and had the same problem. It was incredibly maddening because before I replaced the transformers, I could turn the backlight way down and the set would still work, but after I removed the transformer, 2-5 sec. then no pic. Now I'll have to dig it up and order 1 more.

[budm]

Re: need help to test inverter transformer

Thanks for the feedback, I still wonder what the difference is between the transformers. I sure like to read the inductance of the two transformer to see if they are the same.

[woaimi]

Re: need help to test inverter transformer - solved

update.....

While I ran out of things to check and test, I suddenly realized someone's note while I was on the quest to search for a cure (couldn't remember where I read it from) about the Darfon transformer inverters that for some reasons they are extra sensitive to the each other. I purchased 2 of the new 3 transformers from a chinese vendor on ebay and later purchased the 3rd from another vendor in US (to shorten the shipping time). I thought that might be a problem so spent another $10 with the same vendor where I got the first 2 transformers. I got the shipment in 20 days (ridiculously long) soldered it in and ....
VOILA! the set is back to life
thank you everyone for being very patience with me. I picked up quite a few tricks and skills for my own. The family is very grateful. All cost and time are donated.
I already have another tv to work on and will tackle it when I get a chance, so more questions are on the way.

[woaimi]

Re: need help to test inverter transformer

I'm back...whew! it took forever to get my shower valve replacement from Price Pfister via warranty policy.

Anyhow, I'm ready to get back on the tv again, wonder if anyone has any idea to tackle this problem.

A quick recap of the status at this point:
The screen would turn on a few seconds then goes black, sound still on and I'm able to see the screen with a flash light. It pretty much is a "2 seconds to black" problem. All 3 transformers were replaced with new ones, all components passed the initial tests throughout the whole thread. Any thought is much appreciated.

[lilmonk3]

Re: need help to test inverter transformer

Woaimi.. Did ya get anywhere on this set yet??

[woaimi]

Re: need help to test inverter transformer

should I expect to see the light bulb stay on for as long as the tv is on?

[budm]

Re: need help to test inverter transformer

OK, it does not use U-SHAPE tube but the two tubes are coonected in series to form one tube, so there is no ground return wire. You can try hooking up CFL lamp to the Blue and White wires.
See spec sheet of the LCD panel.

[woaimi]

Re: need help to test inverter transformer

I snapped a couple photos of the lcd and the bulb connector, hope they'll help. The connectors are the only thing that are visible from the lcd, I'll open the case when I have a chance. The bulbs connectors mark JST04 10A, the color on those wires are baby blue and white.

[budm]

Re: need help to test inverter transformer

OK, it sounds like the inverter was trying to startup (you get about 70V, but more likely to be higher AC signal that your meter cannot handle).
I do want to use the test lamp at this point, I never try with TV inverter yet, I am not sure if your TV uses U-SHAPE or Straight setup, if they are a straight lamps, then there should be small lamp return wires back to the inverter board or may be tied to the chassis some where, you will have to look real close. See PDF for details.
You may be able to use T5 12" LAMP for testing, not sure it will work since I do not try it yet but I will.
http://www.amazon.com/10pcs-F8T5-CW-...words=t5+12%22
Can I get the model number of the LCD panel so I can search for the spec sheet to see what it uses?

[woaimi]

Re: need help to test inverter transformer

I desoldered the transformers (all 3) brought it to the guy who works with electronics for all of his career here and asked him to test it out. I couldn't managed to stick around to see how he tested them but he said they are all working properly. There's no fuse that I can spot on the inverter side of the board (it's ps and inverter on the same board)
About testing backlights, it sort of embarrass to say that currently I have only laptop bulbs to mess with and I broke couple of them already from just trying to get it out of it shell, so I was hoping I can find another way to test those bulbs. I will open another old laptop screen and try again tonight, hope I don't break them again.

[selldoor]

Re: need help to test inverter transformer

Ok so on that basis all seems to work except the back lights which shut down
irrespective of the main board. This seems to suggest a problem with the
Inverter board or the lamps.
Can you recheck the secondary windings on all three transformers and check any fuses on that board.
Were you ever able to find or make a bulb to substitute in a lamp test.

[woaimi]

Re: need help to test inverter transformer

OK this is what the set behavior. As soon as power cord plugs in (without a need to press the ON button) the set comes on for about 5 seconds, shows a perfect screen then the screen goes dark. Sound is still on. The blue led that came on when plugged in power still blue. I'm able to see the screen content with a flashlight. If I press the power button to turn it off then on again I would see that same behavior repeat again.
I disconnected the t-com board from the main board, the screen come on a few second flashes away then come back a few second then gone. So, it's pretty much the same with the t-com connected, with just a blank screen.
I tested 1 bulb at a time with the others disconnected. I can see it flashed on went away and flashed back on within 5 seconds then stay off after that. All bulbs show the same pattern.

[selldoor]

Re: need help to test inverter transformer

Will need Budm to comment on that - can you give us a rundown again on what happens when it is all connected and with a working source, from plug in via power on to stable fault position. What do any leds do what does the screen do - any sound any noises - clicks etc.
Disconnect the cable from the main board to the Tcon and try again.