Fujitsu-Siemens P17-2, likely bad transformer but cant find specific model

[DeerDance]

Hi, this is like 3rd monitor I am trying to repair. So quite noobish.

Monitor has 2 seconds to black.
I changed all caps except the big one. That was few months ago.
Now I got to it again, removed transformer and measured the resistance on the the side that has 4 connections, between the red and blue pairs and got jumpy usually settling at 0 so being shorted

So next logical thing is order new one from aliexpress or somewhere, but I just cant google it out. The labeling given on the trafo itself brings nothing useful. I tried googling out schematics of the board that I might get something from there, but no luck, either dead link or nothing.

thnx for help.

Monitor: Fujitsu-Siemens P17-2
Model: s26361-k979-v150

The board labeling: TDK EA22B295T TBD295A TBD295A-1

Transformer labeling: 28LEC-T84 SRW/LF
Transformer labeling: T1 TDK X 0536

pics

[R_J]

Re: Fujitsu-Siemens P17-2, likely bad transformer but cant find specific model

That transformer is NOT your problem, That is the main power supply transformer and not just for the backlights, the low resistance readings are normal.
You likely have a bad ccfl lamp or maybe one of the backlight transformers but I suspect a bad ccfl.
Un plug all the ccfl lamps, then plug in only one and see if you get the backlight to flash, If it does that lampis likely ok, unplug it and try the next one. If one does not flash for a second it is likely bad.

[DeerDance]

Re: Fujitsu-Siemens P17-2, likely bad transformer but cant find specific model

Thnx for reading and directions.

Ok, here is how the test went.

I put the transformer back, and hooked it up except the 4 leads comming from the side.
I connected the fist one and turn on the monitor.
Observe.
turned it off.
Disconnected it and connected second, and so on.



So...

When I connected 1. the picture came on like before, but the area around circled transformer was making weird sound.
It repeated when I connected only 2.
When I connected 3. it didnt made strange sound, screen came on fine, but as I was about to turn off to go for the last it all turned off including power led before I turned off the switch.
Nothing came up when I connected 4.

I connected all four, nothing. on off few times, looking around. I noticed power led faintly blinking.
Then smoke started coming up from behind the transformer area.

disconnected all, one of the 4511GM transistor being noticeably burned



Could that be the failing element finally giving completely in, or just its failure is result of previous components failures?

Thnx.

[R_J]

Re: Fujitsu-Siemens P17-2, likely bad transformer but cant find specific model

That component is likely a power mosfet, Looks like AP4511GM , It may be the only failed component or it could be the high voltage transformer that it drives.
You can usually compair the resistance of the secondaries of the two transformers, if this transformer measures quite a bit different it might be bad also

Also have a close look at C147, it looks like there may be a dark mark on it, It might be bad, if it is bad I suspect it might just be the cap and fet defective

[DeerDance]

Re: Fujitsu-Siemens P17-2, likely bad transformer but cant find specific model

Thanks, will measure tomorrow transformer and cap, order mosfet and report back.