Samsung SM 205BW Screen Flicker, Requesting cap selection help.

[DWChris]

I have read the forums and have seen that this is a problem that can be resolved by replacing the capacitors. I have not seen my revision of the circuit board though so I am requesting help in selecting the correct capacitors. In the picture I have the caps numbered. The ones that are bulging are numbered 1 and 2. Here is the information on the caps.

1. 1000uf 25v, KF105C, C715, VENT
2. 1000uf 25v, KF105C, C713, VENT
3. 470uf 25v, YXG, TO635, 105c, PET
4. 1uf 50v, C715, KF105C
5. 22uf 50v, C715, KF105C
6. 180uf-450v, HP VENT 105C, -NEG

If anyone can help me to pick the correct parts to order from digikey that would be fantastic.

Thanks,
-Chris

[jetadm123]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

Unless the 180uf cap is also bulged, you generally do not have to replace it.

Go to digikey.com:

1) In the search window enter:

panasonic FM 1000uf 25V and select "GO"

2) Select the cap that's in stock and of the correct height and diameter.

3) If your value is not in stock or available, then substitute "FC" in place of "FM".

4) Perform this search for each cap you listed.

[tom66]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

The user reports screen flickering, the main cap failing can cause this so would be advisable to replace it at the same time anyway. In fact a bad main cap can kill secondary caps too so I would say replace it, it's only a couple of bucks.

[DWChris]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

Thanks. Just for my personal curiosity what do the "FC" and "FM" represent?

Of the information on the existing caps what does the "C713", "C715" signify if anything?

[tom66]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

FC and FM are Panasonic's series for capacitors. Both FC and FM are low-ESR and high reliability, but FM has slightly better performance (generally a longer lifespan) for only a couple of cents extra. However, Digikey doesn't always stock all FM caps so sometimes you have to choose FC.

Main cap: http://www.digikey.com/product-detai...2788-ND/758001
(No issue that it's 85°C, as it is in a low-stress environment.)

BTW, that series on your board sounds like CapXon. I've replaced more of those than any other. Most other users have similar conclusions. CapXon are awful capacitors.

C713, etc. is a reference designator (refdes), basically a map for a schematic or parts list identifying each component.

[DWChris]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

Yes they are CapXon.

Thanks for clarifying the designator and the series information

Will update as I progress.

[mariushm]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

If you can't find FM, pick FR ... it has the same or better performance as FM series but it's a newer series from Panasonic. It is however optimized for smaller diameter so in some cases they're a bit taller than the FM series capacitors.
Just make sure they're not too tall if you choose them.

[DWChris]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

SO I have a parts list going. I was able to find fr,fc,fm for all but the last 2 caps in the list. I found a Panasonic EB cap for the 1uf 50v and the one suggested for the 180uf 450v. I have attached a spreadsheet list with links to the caps. Does it look sufficient?

Thanks,
-Chris

[mariushm]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

When you can't find something good, an alternative is to pick a capacitor of the same capacity value but a higher voltage rating.
The only problem with this is that the diameter or height can be bigger when going to the next voltage.

The EB is not good enough, in theory, for that 1uF.

You can safely go for these

1uF/50v :

http://www.digikey.com/product-detai...1360-ND/755876
http://www.digikey.com/product-detai...421-ND/3134377

That 180uF one you probably don't need to replace, but if you do your biggest concern is to get one that's not to wide in diameter - the height is not important as it sits horizontally.
So it's probably 25mm diameter by 46 mm wide, as that's what datasheet says. What you chose is ok at 22mm wide but it's only rated for 2000 hours at 85c, we can do better:

10k hours @ 105c http://www.digikey.com/product-detai...355-ND/3134311
3k hours @ 105c http://www.digikey.com/product-detai...1677-ND/483275

[DWChris]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

Thanks Order going in tomorrow.

[DWChris]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

I received my new caps today and couldn't wait to fix the monitor. So I pulled out my static/soldering mat and went to town. Only burnt my finger once putting in the new caps lol. Its a good one to the skin went immediately white haha. Got it all back together and plugged in the cables and fired it up and nothing...... in my excitement I forgot to plug the video cable into the computer Works like a charm. No flickering just comes on like it is suppose to. Its back on my wife's desk where it belongs

Thank you to those who helped and to this great forum. I now have my monitor back functioning 100% for less than $14.

[roseorufa]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

My Samsung 205BW just died with the standard problem. Blue power light on and nothing else - no obvious image with a flashlight. I disassembled the monitor through the help of many good links through a Google search, removed the Power Board. The board has the dreaded CapXon capacitors, although there is no apparent obvious sign of failure (image attached).

I am certainly not a soldering expert and had actually ordered another monitor before I came across this site/forum. However, I would like to try to resurrect the old one. As others have observed, boards are available on line and board swapping would be the easiest option although the actual board (FSP-050 1P1-01) is relatively expensive ($50) relative to the next version of this board (FSP-050 1P1-02) being about half this price.

The obvious thing to do would be to change the caps and if it still does not work, the board. However, if the cap replacement does not work, is the next most likely failure of this monitor also on this board? Any guidance from the experts on this forum would be gratefully received.

[selldoor]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

Hi thanks for moving - saves confusion.
Can you just confirm that when you switch on the blue power light comes on and stays on?
Also try again looking for an image its best to get the pc fired up with a known vivid image so that you know what you are looking for. Remember to connect pc to monitor.
Another simple test (If you have a multimeter ) is to check the inverter transformer - this powers up the back lights. (ccfls)
Power off for 5 minutes or so set meter on Ohms 2000 and test across pins S1 and S2 and S3 and S4 as in the attached picture, and post the results.

Can you also confirm that the screen does not flash on briefly when
switched on.

[jetadm123]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

If you're getting at least a power light, then the power board is putting out voltage. Take your meter and measure the DC voltage of each wire on the wiring harness on the power board.

[roseorufa]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

I can confirm that the blue power light comes on and stays on and cannot be turned off via the switch on the front bezel. It can only be turned off by the main power switch on the monitor.

There is no obvious flicker at all, the monitor stays "black".

I do have a multimeter, but I cannot see on the power board, the transformer that you refer to. Is it somewhere else?

[roseorufa]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

If you're getting at least a power light, then the power board is putting out voltage. Take your meter and measure the DC voltage of each wire on the wiring harness on the power board.

I'm not an electronics export so please advise:

Is that the 9 wire harness that connects the power board to the next board? Do I measure the DC voltage of each black wire against the red one, and can I do this on the back of the board? I assume that I measure the voltage after connecting the power board to the mains and then turning the switch on.

[selldoor]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

I do have a multimeter, but I cannot see on the power board, the transformer that you refer to. Is it somewhere else?

It is the Big black rectangle in the centre bottom of your picture.
Measure on the other side of the board - if it only has 6 pins
measure across the 2 outside pairs - power off-

Is that the 9 wire harness that connects the power board to the next board? Do I measure the DC voltage of each black wire against the red one, and can I do this on the back of the board? I assume that I measure the voltage after connecting the power board to the mains and then turning the switch on.

Yes its that 9 wire connector - its does need to be all connected and switched on - set meter on 20vDC or autorange and put your black lead on an earth screw then with the red lead measure each pin. It may say on the board what the voltage should be.
List results as
Pin No Should be Measured
pin 1(red) 12v 12.01v
pin2 5v 4,47v and so on


Earth Screw + "Ground screw" in american

[DWChris]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

Just an update. 2 months later and the monitor is used 12+ hours a day and is still functioning perfectly. Thanks again everyone

[roseorufa]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

I'm a pretty competent microbial biochemist but not an electrical engineer, so please forgive my naivety. I've attached a picture of the back of the board through which the transformer attaches. The transformer area is outlined in black, so the soldered connections seem to be aligned vertically, so please let me know which pins I should be measuring the voltage across. I'm also assuming that I need to reconnect the board for a bit, turn it off and then measure the voltage rather than being able to do this on the disconnected board that has been out of the monitor for a week!

[selldoor]

Re: Samsung SM 205BW Screen Flicker, Requesting cap selection help.

Hi - Not a problem I know nothing about more things than I know anything about.
Dont actually know that much about this. Anyway I have marked the test points you will need to carefully remove the glue. ( It does not need to be replaced)
Best not to switch the set on - you are measuring resistance ( Ohms) not voltage.
Set your meter to ohms 2000 or autoranging.

THEN for Budms test you do need to switch it on and keep it on. REMEMBER although the connector is low voltage there are high voltages up to 400volts on parts of the board and
possibly 1200-1500volts on the inverter transformer - perhaps that is why they have the glue on.
Heatsinks although they look safe can carry a voltage which will give you a nast jolt so dont touch them either.