Samsung Syncmaster 245B - Screen freeze -> screen flash 4 diff colours

[drkbef]

Hello,

My monitor has experienced a major malfunction. The screen will randomly freeze, and then get uncontrollably brighter and brighters. Sometimes I can use ctrl+alt+del to snap it out, but now it starts rotating the same four screens over and over again. It will switch from dark, to white, to blue and to red-gren-blue-white stripes.

I searched Google for some answers, and best I could find was this video on Youtube which demonstrates the exact issue I'm having:

http://www.youtube.com/watch?v=5ulXm4Wix5k

The poster was able to get Samsung to replace it, however, my warranty expired back in July. What could be wrong, and what is my best option? I would like to see if it is fixable since it is so hard to find any 16:10 monitors for a decent price anymore.

Thanks!

[retiredcaps]

Originally Posted by drkbef

What could be wrong, and what is my best option? I would like to see if it is fixable since it is so hard to find any 16:10 monitors for a decent price anymore.

It could be capacitors. You will have to open up the monitor and look at them.

For best picture quality and clarity take your boards to a window on a sunny day, turn flash off, and use macro mode. Take a top down view of all your boards (front and back). Make sure the photo is legible so that we can read the PCB printing clearly. A shutter speed of 1/125 or faster will produce nice clear focused pictures. Try to get a photo that is 2000x2000 resolution or as close as possible.

Here is an example of the pictures we want.

http://www.badcaps.net/forum/showpos...94&postcount=1

You can post pictures here and member can help you. Please follow the guidelines in my sig file below.

[drkbef]

Thank you for your kind reply!

I will do as you ask later in the week when I have time.

[drkbef]

Sorry for the ridiculous delay in getting these images. Just started a new job and things have been hectic.

Anyway, I have some even closer shots of the boards done in sections should you require. Please let me know.

Thank you again for your attention and help!

[retiredcaps]

Originally Posted by drkbef

Anyway, I have some even closer shots of the boards done in sections should you require.

1) The pics you supplied are excellent. Clear and focused. I wish more people could do the same when asking for help.

2) You have at least 2 domed/bulged (I'm sure you can determine which 2 are obviously domed) caps by connector CN801 (bottom right hand corner). At minimum, I would replace all 4 in that section.

3) There are 15 electrolytic caps in total. Since this is a nice big monitor, most here would recommend replacing all of them except the largest one which rarely, but not never, fails.

4) Capacitors (C designation on the PCB board) die from age, heat, and shoddy build quality. Capacitors DO NOT have to be visibly bloated in order to bad. They can be out of tolerance uF (a 1000uF measures 20uF) and/or have high ESR (ohm). A multimeter will be insufficient to test for ESR. For that you need an ESR tester which costs between $50 and $300.

5) PCBONEZ talks about how to choose the right series at

http://www.badcaps.net/forum/showpos...47&postcount=3

6) If you don't want to do all that work in step 5, then choose Panasonic FR, FM, and FC caps (in that order of preference) from digikey following PlainBill's ordering instructions at

http://www.badcaps.net/forum/showpos...33&postcount=2

[PlainBill]

Originally Posted by drkbef

Sorry for the ridiculous delay in getting these images. Just started a new job and things have been hectic.

Anyway, I have some even closer shots of the boards done in sections should you require. Please let me know.

Thank you again for your attention and help!

Excellent pictures. I've marked one of them up and attached it.

Two caps circled in red - obviously bad. The must be replaced with low ESR name brand caps, such as Panasonic FM series.

Caps circled in yellow. The recommendation is to replace them with low ESR name brand caps such as Panasonic FM.

Cap circled in blue. Replace if you wish; it is unlikely it is bad.

Shucks, retiredcaps beat me to it.

PlainBill

[retiredcaps]

Also this monitor has problems with the resistors burning up. The three that are suspect are the ones just right of the BN44-00175A. I believe they should read 68 Ohms as per this megathread ...

http://www.badcaps.net/forum/showthr...=245b+resistor

Since you have the monitor open, it is best to test them now and compare them to the color band as per

http://en.wikipedia.org/wiki/Electro...r_and_inductor

Even if they are good, you might want to pre-order spares along with the replacement caps to save on future shipping.

[drkbef]

Wow, such quick replies, you guys are really impressive!

This is my first time with any electronics repair, and it is kind of intimidating. I'll have to do my research this week on how to replace caps on a board.

Thank you both RetiredCaps and PlainBill, you're both great!!

[retiredcaps]

Originally Posted by drkbef

I'll have to do my research this week on how to replace caps on a board.

This site has a good recap tutorial at

http://www.badcaps.net/forum/showthread.php?t=485

Good soldering video at

http://www.youtube.com/watch?v=I_NU2ruzyc4

If you are not going to do another repair in the future, maybe get one of your family/friends to replace the caps for you.

If you are going to replace the caps on your own, then maybe practice on a couple of junk boards?

[drkbef]

Sadly, I don't have anyone that regularly solders electronics... My only option would be to learn myself, or just buy a board :P

[drkbef]

I was looking at getting one of those capacitor kits sold on ebay. I messaged the seller, and these where the ones he said came in the kit:

1 - 10V 2200uF, Panasonic FM
2 - 35V 1000uF, Panasonic FR
2 - 10V 1000uF, Panasonic FM
1 - 35V 470uF, Panasonic FM
1 - 50V 100uF, Nichicon PWM
1 - 63V 68uF, Panasonic FC
2 - 50V 47uF, Nichicon PWM
1 - 10V 47uF, Panasonic FC
1 - 50V 22uF, Panasonic FM
1 - 50V 10uF, Panasonic FC
1 - 50V 1uF, Panasonic FC
1 - Resistor µF-3 2w (That triple resistor that often fails in this model monitor)

Cost to me would be 16.95 US + 6.95 shipping (I'm in Canada)

I don't understand the mixing in of the Nichicon capacitors with the Panasonics... Maybe he doesn't have the equivalent Panasonics on hand.

Do these look like they will work?

Thanks,

[retiredcaps]

Originally Posted by drkbef

Cost to me would be 16.95 US + 6.95 shipping (I'm in Canada)

See below.

I don't understand the mixing in of the Nichicon capacitors with the Panasonics... Maybe he doesn't have the equivalent Panasonics on hand.

He probably doesn't have stock in hand and uses substitutes which is fine.

If you follow PlainBill's quick instructions at

http://badcaps.net/forum/showpost.ph...&postcount=399

you can find out that ordering on your own will save you a few dollars and you get all Panasonic caps.

I did it just to see what the markup was. Keep in mind that the ebay seller is making much more because he buys in bulk whereas this is only quantity = 1 or 2.

1 1 P12357-ND CAP ALUM 2200UF 10V 20% RADIAL 0 0.91000 $0.91
2 2 P14445-ND CAP ALUM 1000UF 35V 20% RADIAL 0 1.08000 $2.16
3 2 P14378-ND CAP ALUM 1000UF 10V 20% RADIAL 0 0.65000 $1.30
4 1 P14441-ND CAP ALUM 470UF 35V 20% RADIAL 0 0.76000 $0.76
5 1 P12392-ND CAP ALUM 100UF 50V 20% RADIAL 0 0.48000 $0.48
6 1 P10341-ND CAP ALUM 68UF 63V 20% RADIAL 0 0.51000 $0.51
7 2 P10321-ND CAP ALUM 47UF 50V 20% RADIAL 0 0.36000 $0.72
8 1 P11180-ND CAP ALUM 47UF 10V 20% RADIAL 0 0.47000 $0.47
9 1 P14452-ND CAP ALUM 22UF 50V 20% RADIAL 0 0.35000 $0.35
10 1 P10316-ND CAP ALUM 10UF 50V 20% RADIAL 0 0.35000 $0.35
11 1 P10312-ND CAP ALUM 1UF 50V 20% RADIAL 0 0.35000 $0.35
12 3 PPC68W-2CT-ND RES 68 OHM METAL FILM 2W 5% 0 0.58000 $1.74
Subtotal $10.10
Shipping $8.00
GST unknown
HST unknown
Total unknown

[retiredcaps]

One other MAJOR thing. Manufacturers routinely make revisions and sometimes completely change boards. So CHECK your board with the capacitors above BEFORE ordering.

PS. Also make sure the height and diameter are okay for your board.

PPS. Now would also be a good time to add other things (maybe soldering items) to the digikey order to "ammortize" the $8 USD shipping/handling.

[retiredcaps]

I should mention that the PPC68W-2CT-ND part number came from the 245B megathread at (thanks to PlainBill)

http://www.badcaps.net/forum/showpos...&postcount=334

Feel free to substitute as you see fit.

[drkbef]

Thanks for the heads up to double check my board.

Oddly, my board has 3x 47UF 50V instead of 2 of those and a 47UF 10V. I would have been really confused what to do with that 10V when it arrived :P.

[drkbef]

I forgot to add, the three resistors on the bottom that everyone recommends to replace are all stuck together with this weird yellow gunk. I tried to gentle wobble the resistors, but this stuff has a death grip on them. What is it and how do I safely remove it so I can replace the resistors?

[retiredcaps]

Originally Posted by drkbef

I forgot to add, the three resistors on the bottom that everyone recommends to replace are all stuck together with this weird yellow gunk.

That was new white glue when assembled at the factory to hold the components in place. After time and heat it turns color and can be conductive.

I tried to gentle wobble the resistors, but this stuff has a death grip on them. What is it and how do I safely remove it so I can replace the resistors?

You can use whatever (exacto knife?) to remove it and when you replace the resistors just install them that so they are not touching. You don't have to replace the glue, but I think you can use silicon caulk to hold them in place to ensure they don't touch.

[drkbef]

I have finally finished the job. While I am not happy with a lot of the solder joints I made (if you look at the picture), my monitor is, however, functioning right now, so that has to be a good sign! I am staying guarded because the monitor would work for a while before having issues, so we'll see. I also changed the resistors and scraped most of the yellow glue off. After more research, and an inability to find silicon that I was 100% comfortable using on my board, I opted to use heat shrink tubing to insulate them. It seems to be working OK with less mess.

I wanted to sincerely thank you both, retiredcaps and PlainBill. It was your help and kind support that gave me motivation and confidence to attempt to fix this myself.

Thank you!

[retiredcaps]

Originally Posted by drkbef

It was your help and kind support that gave me motivation and confidence to attempt to fix this myself.

Good job. Glad you got it working.