Samsung Syncmaster 245BW

[antok86]

Re: Samsung Syncmaster 245BW

Replacing those are the next step. From Digikey P12411-ND Panasonic EEU-FM1V221 would be my suggestion.

PlainBill

okay thanks ill order some and try that. so your saying its not a psu board problem?

[PlainBill]

Re: Samsung Syncmaster 245BW

okay thanks ill order some and try that. so your saying its not a psu board problem?

I don't know. You bring up a good point. Let's start with a little background. The problem you are seeing is called 'Two seconds to black'. It occurs because the inverter controller sees, or thinks it sees, something wrong in the operation of the inverter. Real problems can include a bad transformer (you have eliminated that), bad wiring to a CCFL, or a bad CCFL (draws too much current or is broken). False problems include bad capacitors in the inverter or the power supply, and a bad component in the protection circuitry.

What we have to do is balance time vs cost vs convenience when trying things. Testing the transformers was quick, cheap, and easy. Replacing all the CCFLs and wiring harnesses is slow, expensive, and difficult. Substituting known good CCFLs is easy if you have a similar monitor on hand.

I keyed on the caps because 'Sam Young' is a cheap Chinese brand in the 'replace on sight' category. If you are in the US, it would cost under $5.00 for 4 caps plus shipping from Digikey, delivery would take two days. To me that qualifies as quick, cheap, and easy. At a very rough guess, replacing the caps on the output of the 24v (inverter) supply would cost under $5 more if they were ordered at the same time. And of course, a complete recap of the power supply isn't a bad idea either. That could boost the total cost of the order to $15 - $20.

PlainBill

[antok86]

Re: Samsung Syncmaster 245BW

I totally with you on this. Now when you say two seconds to black does it matter how it turns to black? Mine doesn't go out to black instantly. It flickers like its struggling to turn on then goes off

[Scenic]

Re: Samsung Syncmaster 245BW

flickering backlight on samsung LCDs usually just means bad caps.. especially if it does actually work for some time or it works after warming up..
(unless it was used (despite the flickering) for too long and it damaged other components..)

i'd say go ahead and do a full recap. that's the only way to really rule out a cap problem.

[antok86]

Re: Samsung Syncmaster 245BW

okay i changed the "BIG" cap not sure if that didnt anything since i didnt test it without the back casing but it works now..but with one problem only with the back casing off. when i put it back on it goes back to flickering then going black.

EDIT:i See some ARC on the inverter area when i press down the the silver covering that goes on top of the inverter

[antok86]

Re: Samsung Syncmaster 245BW

The arc was causing the screen to go black so I just covered the area with electrical tape and now I don't have any problems. Not sure what is causin it

[Aruba]

Re: Samsung Syncmaster 245BW

Isn't there an clear insulator sheet that goes in between the board and
the shield cover ? I think that is shown on the left hand side of your picture.
Do you see any arcing marks on the shield in the area you added the electrical tape ?
In any case the electrical tape seems to be providing you the needed
insulation and should work for the long haul but if you were curious and want
to know exactly where the arcing spot is we will need to dig into it a little
more.

[Nog]

Re: Samsung Syncmaster 245BW

It works. Can't tell you what happiness this has brought. No longer have to use my spare 20" Belinea. Many many thanks to you all, you have provided me with a fix for £2 - £3 where Samsung would have charged me £130. BTW the resistors I bought first were way too large to fit on the board so I went to some 68R 2.5W ones with long leads and they were perfect even with some dubious soldering.

[Rtech]

Re: Samsung Syncmaster 245BW

Nog, delighted you are OK now....I said earlier 5W. would be overkill for this PCB.

[antok86]

Re: Samsung Syncmaster 245BW

Isn't there an clear insulator sheet that goes in between the board and
the shield cover ? I think that is shown on the left hand side of your picture.
Do you see any arcing marks on the shield in the area you added the electrical tape ?
In any case the electrical tape seems to be providing you the needed
insulation and should work for the long haul but if you were curious and want
to know exactly where the arcing spot is we will need to dig into it a little
more.

yes there is but then theres the silver lining also thats on the plastic. it doesnt arc on the whole plastic cover just on the upper part which i just covered with electrical tape to insulated it

[blblb]

Re: Samsung Syncmaster 245BW

hi.

I have the same problem as a couple of people before me. I have the 5.2V standby voltage but no 24V or 5.3V.
- the 68ohm resistors are fine, fuses are fine
- no capacitors seem bulged,
- there is vcc on the F9222l and ICE3B....
- the PFC is working since there is 380V on the CP803( fattest capacitor

Ironically the F9222l was replaced and the problem remains.
I don't have an ESR meter so I cannot test capacitors. From what my father (he fixes stuff like this) can see the F9222l simply isn't oscillating.

edit: the next step is probably measuring what kind of output the f9222l gives out with an oscillator (needs to be isolated first)

Anybody has any ideas???

[jetadm123]

Re: Samsung Syncmaster 245BW

hi.

I have the same problem as a couple of people before me. I have the 5.2V standby voltage but no 24V or 5.3V.
- the 68ohm resistors are fine, fuses are fine
- no capacitors seem bulged,
- there is vcc on the F9222l and ICE3B....
- the PFC is working since there is 380V on the CP803( fattest capacitor

Ironically the F9222l was replaced and the problem remains.
I don't have an ESR meter so I cannot test capacitors. From what my father (he fixes stuff like this) can see the F9222l simply isn't oscillating.

edit: the next step is probably measuring what kind of output the f9222l gives out with an oscillator (needs to be isolated first)

Anybody has any ideas???

The vcc on the F9222.. and ICE..., are they within specs? Are they fluctuating?

Have a look at post #51 of this thread.

[blblb]

Re: Samsung Syncmaster 245BW

The voltage on the ICE is within specifications but it rises from 12V to 15V and then back to 12V and it keeps doing that.

Voltage on f9222l is 18.6V (stable)

ICE voltage seems mighty strange to me... although nothing was connected to the board.

[jetadm123]

Re: Samsung Syncmaster 245BW

The voltage on the ICE is within specifications but it rises from 12V to 15V and then back to 12V and it keeps doing that.

Voltage on f9222l is 18.6V (stable)

ICE voltage seems mighty strange to me... although nothing was connected to the board.

Looks like the ICE is trying to start up. Usually, on these type of controllers, you have a diode and a startup cap connected off of a tertiary winding of the main transformer that supplies the Vcc pin of the controller chip. The cap is typically 22uf-47uf. Check the diode and if it checks ok, try replacing the startup cap.

[blblb]

Re: Samsung Syncmaster 245BW

Well I replaced the 22uF capacitor and the problem remained. I then hooked everything to the board except the LCD screen itself and the voltage stabilized at 15.5V, so the capacitor wasn't dead

Unfortunately I still don't have 5.3 and 24V.

The only thing I could try to replace is the NPN transistor that some people had problems with. But mine seems fine...

[jetadm123]

Re: Samsung Syncmaster 245BW

Well I replaced the 22uF capacitor and the problem remained. I then hooked everything to the board except the LCD screen itself and the voltage stabilized at 15.5V, so the capacitor wasn't dead

Unfortunately I still don't have 5.3 and 24V.

The only thing I could try to replace is the NPN transistor that some people had problems with. But mine seems fine...

You will probably have to post some good focused photos of top and bottom of the entire power supply, since there's apparently a few different versions of it. Do not post inline. With that being said:

1)The ICE produces the 5V standby. Verify this by measuring across CB876 (1000uf 10V cap).

2)Without the 24V output, you cannot get the 5V, since the 5V is generated from the 24V.

3)With power off. Go to post #45 of this thread. There's a diagram of F9222L. The F9222L generates the 24V output. On the diagram, there's two mosfets, Q1 & Q2 inside the F9222. Check these mosfets for shorts.

4) The NPN transistor you mentioned. Same one as in post #51 of this thread? If yes, check it for shorts.

5) Also, check resistor RB805, 68ohms.

[Perineum]

Re: Samsung Syncmaster 245BW

Just wanted to let you know that I've had success repairing my monitor.

I replaced every capacitor on the board, simply because it's easy, cost be about $10 and I don't want to fix it twice. However, that didn't fix it.

I checked the three 68 ohm resistors and they were dead, even though they looked perfectly fine. I ordered three metal film 68 ohm 3 Watt (+/- 5% and 750V rating) Vishay resistors and installed them.

After reassembly the monitor turned on without any drama. YAY!

Thank you very much for documenting this so well....

[kehall]

Re: Samsung Syncmaster 245BW

Hi, sorry if hijacking a thread but had read mention of flickering earlier on and wanted to clarify/ask a question please in terms of the flickering.

I have a 245B which is just over 3 years old now, I use it with DVI connection 1920x1200 on Custom Magicbright with brightness/contrast (5/50) as anything else is just too bright..

However there is a persistent background 'flicker' which you can see and I'm sure its giving me headaches... you can mostly 'forget' about it but it is there and I don't think it's helping my head! It doesn't SEEM as noticeable the brighter you go (but is there).

It's like a 'pulsing' around (I'd guess 25Hz) of the entire backlit area most noticeable on plain white) certainly not "in your face" but nevertheless its "there". Side by side with Acer AL1722 (no flicker at all).

I also notice a low frequency audible 'hum' probably around 200Hz...

Is this something that anyone has noticed/fixable?

Regards,

Keith.

[alexanna]

Re: Samsung Syncmaster 245BW

Open it up you'r probably going to find bad caps

[kehall]

Re: Samsung Syncmaster 245BW

Whilst I may do just that out of precaution, given some of the tales earlier in the thread about blowing other components, this monitor has always had this flicker that I can recall (yes I know probably should have mentioned sooner whilst in warranty!), however I want to know if anyone else has seen it (and if it's what is being referred to earlier on in the thread).