Samsung 23" LCD P2350 Inverter Repair

[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

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

OK, that is good to verify.

[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, 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

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

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

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

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

just some pics if anyone notice anything strange

[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

[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

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

Yes Pin 8 power and ccfls.

Have you tested the fuse at F201? that takes the power to the inverter.

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

So I should apply 3v here, like on the picture, with only power board and CCFLs connected?

[selldoor]

Re: Samsung 23" LCD P2350 Inverter Repair

Before you do that there is another thing you can try.

First find a pin on the main board connector labelled pson or pwr
Set it all up but without the main board connected then get a 3 volt battery or 2x1.5v
wire the negative of the battery to ground screw and apply the 3v from the battery
to the psonpin. With any luck the lamps may light.

It is difficult for us to say if there is anything else as we have not seen pictures of your boards.

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

buying 2 test lamps costs a lot... so I am thinking of buying those
checked the voltage regulators just out of curiosity, 3,3V gives 3,29V and 1,8V gives exactly 1,8V so those are fine too
now there is nothing else suspicious other than CCFLs?

[budm]

Re: Samsung 23" LCD P2350 Inverter Repair

I use test lamps for real verification of the inverter function.
Yes, it is very possible to have two bad lamps in the assembly as you can see here:
http://s807.photobucket.com/albums/y...klight%20lamp/

I have los of spare lamps!

[selldoor]

Re: Samsung 23" LCD P2350 Inverter Repair

I dont know plainbills post but retiredcaps has similar in his 2 seconds to black guide. My understanding is that that one lamp test is ONLY a quick test to find out if a lamp (or the wiring)is definitely broken as against being faulty.
Using lamps that you KNOW are good is the best test. -

"Do I need one or two?"

It is easier if you have 2 test lamps.

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

Checked out what PlainBill said about testing CCFLs... Unpluged one connector on the CCFL turned on, same thing 2 seconds to black only the brightness is 50% lower, pluged back in the one that was dsconnected, and disconnected the one that was connected in the previous test and the same thing happened again...

SO! I assume the problem is still in the power board unless both CCFL lamps are dead which I assume is not quite possible?

And the MOSFETS are OK