Samsung 23" LCD P2350 Inverter Repair

[momaka]

Re: Samsung 23" LCD P2350 Inverter Repair

Does anyone know if the 15v, 3.3v & 5.1v output pins can be tested with out the lamps and main board connected?

Looks like yes, because the power board has only one transformer (excluding the inverter). This means the transformer is used both for standby and main power.

[markcoenen]

Re: Samsung 23" LCD P2350 Inverter Repair

Does anyone know if the 15v, 3.3v & 5.1v output pins can be tested with out the lamps and main board connected?

[markcoenen]

Re: Samsung 23" LCD P2350 Inverter Repair

Hi guys,

Another repair of this one.

I need a better shot of the part marked on the attachment.

Or if anyone can tell me what are the R39, R40, R41 and R42 since they
burned out on my board.

I just started working on the same monitor and i can read the 4 parts you are looking for. all 4 are 563

[budm]

Re: Samsung 23" LCD P2350 Inverter Repair

It has two pairs of lamps so four lamps total, I do not have answer for the rest of the questions.
It may have bad solder joint at the end of the lamp.

[Alejandro86]

Re: Samsung 23" LCD P2350 Inverter Repair

I'm sorry to bump this thread up. Its the only post showing up on google regarding ccfl issues (on the P2350).

My lcd screen didn't die (at least its not the black after 2 seconds issue), but it seems one ccfl went out (or tried to), as my room filled with this strange smell and my screen looked fine in the upper areas and faded on the lower ones.

If you don't mind i have a few questions about this:
1) How many ccfl does my monitor have?
2) What is the lenght of such ccfl?
3) A 22 inch ccfl to led kit will give me faded edges (or corners) right?

Thank you very much for your time!

[momaka]

Re: Samsung 23" LCD P2350 Inverter Repair

Or if anyone can tell me what are the R39, R40, R41 and R42 since they burned out on my board.
...
I think its those components that I marked but I dont know what hey are since the whole area burned out.

I don't have this monitor. In case you don't get an answer from anyone else, my best suggestion would be to remove those components and clean the area very well with IPA (alcohol). Make sure there is no carbon deposit left, as that can be conductive.

Those resistors, R39-R42, look like they are on the high-voltage outputs, so they probably have a very high resistance value (I'd say 0.5 MOhms or more). They also appear to have an identical value. Not sure if that would be of any help, though.

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

Replaced every cap (as always jut to be sure), replaced the MOSFETs since they were
severly burned, put everything back together turned ON, everything worked for lets say 5 minutes.

Now its back to start again, keep getting 2 seconds to black.

I think its those components that I marked but I dont know what hey are since the whole area burned out.

[CroTech]

Re: Samsung 23" LCD P2350 Inverter Repair

Hi guys,

Another repair of this one.

I need a better shot of the part marked on the attachment.

Or if anyone can tell me what are the R39, R40, R41 and R42 since they
burned out on my board.

[orangesap]

Re: Samsung 23" LCD P2350 Inverter Repair

I have this monitor. Started getting the 2 seconds to black problem and had some suitable spare capacitors so I replaced them, didn't help though. Got my hands on a DMM and double checked the capacitors and they're all fine. I checked the mosfets as well using diode test and found that I can put positive/negative on any of the white circled pins and it'll connect, if I put positive on the red and negative on any of the white pins it'll also connect but not vice-versa.

http://puu.sh/hZEFV/aad0092ef9.jpg

[erbmit]

Re: Samsung 23" LCD P2350 Inverter Repair

I bought a junked one of these monitors to repair (buttons light up, no image) & found this thread.

My amazement when I realised that I started it 3 years ago!!? I thought those images were rather good!

Old age and senility setting in. I hope this one is an easier issue to fix. I haven't opened it yet, so it may be the same monitor . . . Peter

[madvik]

Re: Samsung 23" LCD P2350 Inverter Repair

Question: Can the FSDM0465R be used instead of the FSQ? pinout looks the same, application range also (LCD monitor smps), but pin 5 is NC (SYNC pin of FSQ0465R) ?

I only ask because: 1. I'm not a pro in electronics;
2. it seems within reach in europe.
Thanks!

[budm]

Re: Samsung 23" LCD P2350 Inverter Repair

"Are there any equivalent ics I can use to get the monitor (hopefully) running?" none that I know of.

[madvik]

Re: Samsung 23" LCD P2350 Inverter Repair

Right. Thank you very much for that.

Now, searched for that full name and no hits around here... it seems it can only be found in the US (20-40$ shipment) or china (freeee shipment but 1-2 months to wait)....

Are there any equivalent ics I can use to get the monitor (hopefully) running?

[budm]

Re: Samsung 23" LCD P2350 Inverter Repair

SMPS IC:

[madvik]

Re: Samsung 23" LCD P2350 Inverter Repair

I have found the (hopefully only) culprit: a six-legged all-plastic mos-style piece (photo1) which aparently had one of the legs (ground it seems) melted from it's upper part (after exiting plastic) and glued onto Vcc. You can check this from the photos to see if i got it correctly.

The main problem is i cannot find any info on it, google knows no pdf, nothing.
Nor the stores can supply it...
Anyone has the knowledge to shed some light over this piece? I'd greatly appreciate it.

If you want more angles on the boards, just say so.

[madvik]

Re: Samsung 23" LCD P2350 Inverter Repair

Hello, guys!

I am reviving this old but very useful thread with my own problem with a P2050, which I think it is P2350's smaller brother.
It is manufactured November 2010, right in my beautiful country.

I've been using it for 2 years and a couple of months (of course no more warranty) when it simply would not turn on anymore. It was put away for when I'd have time to open and view the inside. That time was today.

Once opened I saw both boards looking mint, like it was just out of the assembly line.. What to do? Started looking after the fuse, and found one mini circular red 3,15A "slow blow" fuse, checked for continuity and found burnt.
Now to find it in my city, that will be a big hustle.... (the very beautiful but inhabited country of Romania, Valcea county)

Will post images of the boards for future reference and maybe help to others.

[momaka]

Re: Samsung 23" LCD P2350 Inverter Repair

I'm not an expert with inverter repair, but hopefully that is all you will have to do... just get the new inverter and solder it in. It is not uncommon for these transformers to fail like yours. I think what usually happens is that they develop a short (or multiple) across windings on the output side, and that's when you get excessive heat and meltdown. In some cases, I think this may also be caused by aging CCFLs starting to pull too much current and making the inverter work harder.

Sinc you do get backlight at least for a second, my guess would be that the inverter driver transistors are okay. So yeah, hopefully all should be good with the new inverter transformer.

[bambusha0]

Re: Samsung 23" LCD P2350 Inverter Repair

Little bump.

Read whole thread, didn't really see anyone with this (obvious?)situation. So problem is the same, monitor turns on, then backlight goes off after a second or so, and stays off. On the pic you can see that the inverter melted on that one spot. So, just making sure, I get the inverter from ebay, solder it in place of this melted one, and problem solved? Is there something I can do to make sure it doesn't happen again?

[adamelec]

Re: Samsung 23" LCD P2350 Inverter Repair

Monitor fixed. Turns out Diode "D203" (5V rail secondary rectifier diode) was conducting in both directions.

The inverter chip was going into burst mode due to either overload protection or overvoltage feedback due to there being no 5V rail.

[majkstone]

Re: Samsung 23" LCD P2350 Inverter Repair

I also have the same inverter board, I think someone did a 500V insulation resistance test on the screen an blew it up.

I have tested all fuses. There is 13V on Pin 2, but nothing on the 5V pin 5/6 or the 3.3V pin.

I put the scope across Drain and GND of the SMPS IC (U101) and am only getting switching bursts 500ms apart. I assume this is the low power mode of the chip. Should the chip be in standby mode or is there something wrong here?

chek the other board with vga conn there are the ICs to get 3.3V from 5V chip