Samsung 23" LCD P2350 Inverter Repair

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

F101 and F201 are OK (not blown)
tried putting 3V on pin 8 (2 batteries and tried 3 batteries + on pin 8, - on pin 3 GND) nothing, screen did not power up

[selldoor]

Re: Samsung 23" LCD P2350 Inverter Repair

Just checking - you did have the mains plugged in and on as well as the 3v

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

Main AC plugged in, tried battery like an impuls just touched the wires a couple of times and tried it like a source, holded the wires on the batteries for a like a half a minute, nothing happened

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

just some pics if anyone notice anything strange

[budm]

Re: Samsung 23" LCD P2350 Inverter Repair

Did you install the P-Channel and N-Channel MOSFET's correctly as shown in post 1? Since you asked this question "And if I have the same problem could anyone write it on the picture in the first post which mosfets are IRF540N and which IRF9540N"

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

the picture was not so clear so I had to change focus and contrast so I can see it clearly, I think I got it right...
here is how I soldered them on the board, all the FETs are facing heatsink towards the camera, and so the pins are marked like looking on them that way...

Ithink I soldered them ok...

[budm]

Re: Samsung 23" LCD P2350 Inverter Repair

The main key is that the P-Channel and the N-channel MOSFET has to be in the right locations.

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

So can you tell just by looking in the picture did I put them right?

I didn`t came up with this fix so I am not sure about the solder points

[budm]

Re: Samsung 23" LCD P2350 Inverter Repair

OK, if you look at the pictures in post 1, he had the MOSFET's labeled with "5" and "9"
which I think what his marking means:
5 = IRF540 (N-Channel: https://cdn.badcaps-static.com/pdfs/...23be5e315f.pdf)
9 = IRF9540 (P-Phannel)

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

yup I´ve put them in that order, I also labeled them 5 for IRF540 and 9 for IRF9540 in my attachment up a post...

[budm]

Re: Samsung 23" LCD P2350 Inverter Repair

OK, that is good to verify.

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

I was also wondering, since I have the syncmaster 940n could I test the CCFLs of the P2350 on that power board?
Since the connectors are compatible (I think) I could connect those and try to power up the lamps and see the result... But I am not sure if anything can go wrong

[budm]

Re: Samsung 23" LCD P2350 Inverter Repair

Yes you can, just connect the lamp connectors to the board.

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

Well than I am going to try that...

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

CCFLs are fine, brightness is good and it is working fine when connected to the 940n power board, I left it for a few minutes and worked just nice... No redish color indicating dying lamps

[selldoor]

Re: Samsung 23" LCD P2350 Inverter Repair

Hmm thought I asked if you had anything else to test the panel on in post 68.

Have you re tested your Mosfets since fitting them?

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

I tested the MOSFETs by checking for shorts and using diode check...
I read that any shorts with the gate indicates a faulty MOSFET, so I assume they are ok, since none of them is shorted.

Also you can hear high pitched noise after the backlight shuts down.

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

Is there anything else, any ideas? :/
Could it be the mains cap (the big one)?

[jeranio]

Re: Samsung 23" LCD P2350 Inverter Repair

I have the same problem. Samsung P2350 shuts of backlight after 2 seconds. After reading this entire post, I am not sure which direction to head. Waiting to see if anyone figures out the real reason why backlights switch off. I know without having a complete working module to swap and check this can be daunting fault to find but by now there are have been millions of these made and somebody out there knows a definite way to pinpoint the faulty components with some easy checks.

[Rtech]

Re: Samsung 23" LCD P2350 Inverter Repair

Lots of reasons for the '2 secs to Black' you have...no easy answers unfortunately,just follow the procedure as described in the 'sticky',and hope.