Samsung SyncMaster 226BW

[PadMan]

Re: Samsung SyncMaster 226BW

Hi
I have a Samsung 226BW whitch had the flickering backlight problem.
After exelent advice from this forum I have now replaced the caps.
1x 47uf 50v
1x 330uf 25v
2x 820uf 25v (My local distributer only hade this cap as a 35v. But it fitts, just)
2x 680 uf 25v

To my delight the screen worked once again.
For a few seconds until i got the computer to send a fully light screen.
If the computer sends a dimed screen signal all works fine. But a fully light screen cases the backlight to go out after a second or two.
I can see the image om the screen if I use a flash light even when thou the backlight is not light.
When the screen receives a full light signal the IP-45130A rev 0.1 board starts to make a high pitch screetching sound. It sounds like the noise comes from the power half of the board. But this is more of a gues then anything else.

The equipment i have to work with is basic. A soldering iron and a multimeter, that can not mesure capasitance.

I have replaced this far:
caps listed above
3A fuse as this was also blown
2x 4511GED ICs

I have been scouering the forum for a simuler problem.
I have been stretching my electronics knolage wafer thin.
And this has now become a misson to get it to work.
So any input or suggestions are greatly apreciated.

Many thanks and happy christmas

[edster]

Re: Samsung SyncMaster 226BW

Is that the supply rail that goes to the inverters? Its very common to find badcaps on this 226BW model (sometimes they do not bulge visually but measurements may tell a different story) First of all, replace all the capacitors in the secondary section. If that does not help, then start checking the feedback section (the area around the opto-isolator, including the opto-isolator itself)...

Thank you for your reply Lexwalker,

I have replaced the entire lot of caps on the power supply with Panasonic caps of same type. All of the large caps were bulged at the top (6 of them), the little ones weren't but I replaced them as well (3 of them).

Yes, I measured the fluctuating voltage on the supply rail that goes to the inverter. It fluctuates 14 volts to 0 volts continuously. I would think this should be a continuous 13.5 to 14 volts but my electronic skills are not great.

Thanks

Ed

[lexwalker]

Re: Samsung SyncMaster 226BW

I have replaced the entire lot of caps on the power supply with Panasonic caps of same type. All of the large caps were bulged at the top (6 of them), the little ones weren't but I replaced them as well (3 of them).

What were the model/series used? I've replaced capacitors on quite a number of these monitors though mostly using Panasonic FR and Nichicon HE series. So far I have not much trouble repairing them as majority of the problems were due to badcaps...

Yes, I measured the fluctuating voltage on the supply rail that goes to the inverter. It fluctuates 14 volts to 0 volts continuously. I would think this should be a continuous 13.5 to 14 volts but my electronic skills are not great.

Does the voltage fluctuate even when the backlight is off? Problematic rectifiers (overheating ones) can cause such problems (try replacing them first). If that does not help then try changing the main filter/smoothing capacitor, that big 100uF 450V one, and test again. At the feedback section, check that "431" shunt voltage reference thingy (looks like a transistor, usually have markings such as TL431, LM431, SC431, etc) and try replacing that opto-isolator. Could also be that PWM I.C, but first check all the component around it first before pinning the source of the fault on it...

[alternety]

Re: Samsung SyncMaster 226BW

I have been reading through the thread and have a question. I have (actually my wife has) the target 226BW.

I have seen some references to different versions of the board. I have not seen a way to identify what is in there before hand. I would like to avoid taking the monitor apart, reassembling, ordering, disassembling and reassembling. Amongst other things it increases my chance of breaking something. If I take it apart and wait for parts I will not be fed and will have to live in an external shed. Is there information somewhere that identifies the caps based on a manufacture date or something else fairly easily found?

As an alternative, can the caps called out at the beginning page or two of this thread be used in any version regardless of different specs in later versions? Like 8xx when a later version may have 470mf as I believe was the case in one post. I guess another way of putting this is that I want a universal cap set specification.

[alternety]

Re: Samsung SyncMaster 226BW

I did not get a response to my post above so I went ahead and bought caps. But no 680mf. Not intended; just a mistake after dealing with Digikey's system for a while. I have attached an image of the board and the label on the back. I appears I have the earlier version with 680mf caps in C301 and C302.

I also note that there is an empty space labeled C113 aside of C110. Some board versions have another 820mf in C113.

I am not sure about C107. From reading this thread, I assumed there could be three different values in that position. Mine is 47mf. I got all three values to be safe. That worked.

My questions:

1 - Should I fill C113 if it is empty?

2 - Can I use 820mf in C301 and C302.

A reply soon would be appreciated. My wife will be back in a couple of ours to find her monitor is assorted pieces. It will not be pretty.

[selldoor]

Re: Samsung SyncMaster 226BW

1 No just leave it
2 Yes if voltage is correct and they will physically fit

You didnt say at any point what the problem was but check small green torpedo fuse
at F301

[alternety]

Re: Samsung SyncMaster 226BW

It appears that C301 and C302 are simply across the supply voltage to ground. So I am guessing value is not critical. One supply leg does have a resistor between it and the main input power bus.

C113 adds to the input bus filtering.

[selldoor]

Re: Samsung SyncMaster 226BW

Did you see my post?

[alternety]

Re: Samsung SyncMaster 226BW

No I did not. But I see everything now.

C113 goes from +13V before the inductor to gnd. Presumably that is filtering the raw 13V. The other two 820mf go between gnd and the downstream side of the inductor isolating this trace from the input trace that C113 bypasses to gnd. C113 is the only bypass cap in that isolated power input section of the board.

I will go with your recommendations.

Thanks.

[selldoor]

Re: Samsung SyncMaster 226BW

Ok - so how did it go?

[lexwalker]

Re: Samsung SyncMaster 226BW

I did not get a response to my post above so I went ahead and bought caps. But no 680mf. Not intended; just a mistake after dealing with Digikey's system for a while. I have attached an image of the board and the label on the back. I appears I have the earlier version with 680mf caps in C301 and C302.

I also note that there is an empty space labeled C113 aside of C110. Some board versions have another 820mf in C113.

I am not sure about C107. From reading this thread, I assumed there could be three different values in that position. Mine is 47mf. I got all three values to be safe. That worked.

My questions:

1 - Should I fill C113 if it is empty?

C113 is optional, up to your choice whether to fill it or not. Its located right after a filter choke/inductor. You can fill that empty spot with any capacitor. Usually I would either use 330uF 25VDC (following the original 330uF 25VDC), or 470uF 25VDC (if I replace the other 330uF 25VDC originally on the board with 470uF 25VDC also). See attached first image...

2 - Can I use 820mf in C301 and C302.

A reply soon would be appreciated. My wife will be back in a couple of ours to find her monitor is assorted pieces. It will not be pretty.

It appears that C301 and C302 are simply across the supply voltage to ground. So I am guessing value is not critical. One supply leg does have a resistor between it and the main input power bus.

C113 adds to the input bus filtering.

For both C301 and C302, they are located near the inverter section. Usually the values for these are not that critical. You can use the original 680uF 25VDC, or something higher like 820uF 25VDC or the more common 1000uF 25VDC provided they fit in there (the capacitor height must be 20mm or less, with lead pitch of 5mm). Had plenty of these Samsung SyncMaster 226BWs that came in for repair, thus could experiment around with bigger capacitors. See attached second image...

[alternety]

Re: Samsung SyncMaster 226BW

It fixed the problem. Left C113 empty. I looked at where the caps were electrically first. The 2 that are populated are on the supply after the inductor and C113 was before the inductor. I just left it alone.

After I got it repaired, and my wife assured me I had god like capabilities for fixing it (she is very smart; but a lit major), she told me that there were large square "pixels" on the screen sometimes. This had been going on for a long time. We had a brief discussion around "and why don't you tell me about these things?".

They are not a single LCD bit. The are larger. The are intermittent. Maybe 1/32" square or a bit bigger (from recollection after seeing them). And I saw them after the fix. Had I been aware of this I would have tried to isolate it to the monitor or graphics card replaced the monitor if it was in there.

Anyone have any idea what might be causing the squares. A large number of them scattered randomly, static when they are displayed, go away when it has warmed up. It could be a problem with the graphics card in the PC.

[lexwalker]

Re: Samsung SyncMaster 226BW

After I got it repaired, and my wife assured me I had god like capabilities for fixing it (she is very smart; but a lit major), she told me that there were large square "pixels" on the screen sometimes. This had been going on for a long time. We had a brief discussion around "and why don't you tell me about these things?".

They are not a single LCD bit. The are larger. The are intermittent. Maybe 1/32" square or a bit bigger (from recollection after seeing them). And I saw them after the fix. Had I been aware of this I would have tried to isolate it to the monitor or graphics card replaced the monitor if it was in there.

Anyone have any idea what might be causing the squares. A large number of them scattered randomly, static when they are displayed, go away when it has warmed up. It could be a problem with the graphics card in the PC.

Have you tried swapping monitors and see if this screen artifact also appears on a different monitor? Other than that, could be dirty LVDS connection thus try cleaning the connectors and re-seat the cable again...

It fixed the problem. Left C113 empty. I looked at where the caps were electrically first. The 2 that are populated are on the supply after the inductor and C113 was before the inductor. I just left it alone.

If I recall correcrtly, C113 was after the inductor. You are looking at it from a wrong direction. The two populated ones are the main filter capacitors (both 820uF 25VDC), which is then followed by an inductor. Then after the inductor there is a 330uF 25VDC capacitor there. Usually I will also replace this one as sometimes will fail. Here is another 226BW that just came in. Symptom was having difficulty switching on. Has a different power supply board than the usual one (as shown the first image). See that smaller bulging 330uF 25VDC capacitor (as shown in the second image)? Replacing it revives the monitor. Anyway, gonna replace the rest of those awful Samwha XC capacitors (as there is a slight hint of audible hissing from the transformer)...

[alternety]

Re: Samsung SyncMaster 226BW

Looks like the little guy gave up his life for the big ones. Brave cap. I think you are right about the sequence. I was viewing that connector as power in. It is not of course. What makes me suspicious that it is an output is that big AC socket at the other end of the board and all that power supply stuff around it. Duhh. Old brain, getting older.

I replaced all of the electrolytics. I was not going to save a buck and have to do it over again. I even got the big one. That one cost more than all the others together. But I tend to believe that if is worth doing, it is worth overdoing.

The little squares are not bothering her. And they go away quickly as something warms up. The only reason I am concerned is as a precursor to a bigger problem. That was why I asked if anyone else had seen these and a possible cause. Should that happen then I will swap monitors as needed. Way too much hassle to extract my monitor from my desk.

[lexwalker]

Re: Samsung SyncMaster 226BW

Looks like the little guy gave up his life for the big ones. Brave cap. I think you are right about the sequence. I was viewing that connector as power in. It is not of course. What makes me suspicious that it is an output is that big AC socket at the other end of the board and all that power supply stuff around it. Duhh. Old brain, getting older.

You can find some LCD monitor power supply schematics around. And even looking at those schematics (from left-to-right), can see that small capacitor is after the inductor...

I replaced all of the electrolytics. I was not going to save a buck and have to do it over again. I even got the big one. That one cost more than all the others together. But I tend to believe that if is worth doing, it is worth overdoing.

Well, I also replaced all the crap Samwha XC capacitors including those on the primary side, except for that big one (which looks like a Samyoung based on the sleeve and text coloration). Using Rubycon ZLH series for the 820uF 25VDC capacitors this time, as I've ran out of Panasonic FR series (already ordered new batch). See attached images. Currently putting the monitor through burn-in testing...

The little squares are not bothering her. And they go away quickly as something warms up. The only reason I am concerned is as a precursor to a bigger problem. That was why I asked if anyone else had seen these and a possible cause. Should that happen then I will swap monitors as needed. Way too much hassle to extract my monitor from my desk.

Some pictures of the problem would be useful. Otherwise you could try another PC or laptop on that monitor, if not swapping monitors...

[_Jay_]

Re: Samsung SyncMaster 226BW

Just fixed my 216BW by replacing the caps from page 2 of this thread (post 24, 28 and 29). All the caps listed first in post 28 were available at Mouser. Thanks!!!

[stavros67]

Re: Samsung SyncMaster 226BW

Hello from Greece.
I have a 226BW with IP-43130A board, 226BW-VE REV.0.0, 2007.04.18.
I know what capacitors i want to replace expect the big one C105. I don't know if it is 100uF or 150uF at 450v. I am confused, could someone help me?
Thank you in advance and sorry for my bad english.

[selldoor]

Re: Samsung SyncMaster 226BW

I believe there are different versions of the power supply some have 150uf some have 100uf. You should use the same value that you took out.

It is not usual to change the BIG cap unless it is known to be bad or has signs of leakage
or bulging.

You need to be careful with the height of some caps on this board.

Unless there is no other option do not buy off ebay or online from China.
Use good make caps from a known good seller

[stavros67]

Re: Samsung SyncMaster 226BW

You mean that exist different versions of this particular board (IP-43130A, 226BW-VE REV.0.0, 2007.04.18)? Because i want to replace all the capacitors of the board and consider changing and the big one but i can't see the uF value.

[selldoor]

Re: Samsung SyncMaster 226BW

I dont have time to read all the thread to see which board is which I just know
there is mention that 2268A has more than one. Post a picture of both sides
of your cap -someone may be able to identify it.
To be honest, if in doubt, I would just fit a 150uf cap.

Do you think it looks bulged or leaky?