Samsung Syncmaster 245BW

[Mr.E]

Re: Samsung Syncmaster 245BW

Thanks PlainBill. I originally planned to not replace the others but agree its probably a good choice.

[keithwbloom]

Re: Samsung Syncmaster 245BW

So I am prepared for next steps...

There are currently no caps bulging on power supply board. I have ordered replacements for the three RB80# resistors, and hope to be able to test everything further once the power flows past the burned out RB805.

There is a little scorching between the NT811S inrush limiter and the VX801S behind it. It could just be the inrush limiter has just baked the thermal glue that binds the two to a toasty brown.

First question: do I need to re-glue the two inrush limiters to each other for thermal protection? I may just replace them, I think I have some from a Samsung power supply recap i did this spring.

Second question: on the Samsung PS for my PowerMac I recapped this spring, I also ended up replacing several of the MOSFETs connected to the heat sinks. I think there has been some chatter about the 5-pin ICM852 being suspect in this thread. How do I test them for failure? Do they fail open or shorted?

[keithwbloom]

Re: Samsung Syncmaster 245BW

I let my edit window expire so I am adding to it here. Some other observations/measurements before I replace the burnt RB805 and its siblings:

1. From post 276 in this thread, the voltage measured across CB876 is 5.15 - 5.29V, fluctuatiing relatively slowly
2. From post 41, voltage between pins 7 and 8 on ICB801S is 11-16V, fluctuating fairly quickly.
3. From post 45, votage between pins 8 and 23 is 168V, all other pairs are at or near 0V

And I completely forgot to list my initial symptoms, start-up gets blue power on standby light and black screen from any video source. I am not suffering from a flickering display, it just didn't come back one day when it went to sleep.

Keith

[hydafl]

Re: Samsung Syncmaster 245BW

Wanted to come back and say a huge thanks here for the guidance. 5 minutes of time and we saved another monitor from hitting the trash heap....

[wolf5]

Re: Samsung Syncmaster 245BW

Hi. Just experienced the same thing with my "old" 245b. Having played with electronics since I was a kid, I have no problems opening up and checking around but I am no expert.

Me not remembering the color codes, what replacement resistor do I need to get for the RB805, RB806 and RB807 (watts and ohms)? I have checked all RB807 shows 66.6, RB806 shows 68.0 and RB805 shows 500K ohm.

So it should suffice to change that last one.

[PlainBill]

Re: Samsung Syncmaster 245BW

Hi. Just experienced the same thing with my "old" 245b. Having played with electronics since I was a kid, I have no problems opening up and checking around but I am no expert.

Me not remembering the color codes, what replacement resistor do I need to get for the RB805, RB806 and RB807 (watts and ohms)? I have checked all RB807 shows 66.6, RB806 shows 68.0 and RB805 shows 500K ohm.

So it should suffice to change that last one.

I say you have several options:

1. Google resistor color code

2. Curse the instructor who failed to teach you Bad Boys Rape Our Young Girls But Viola Gives Willingly

3. Recall that 68 is a standard resistance value.

4. Search all instances of RB805, etc in this thread. One of them will have the value.

PlainBill

[keithwbloom]

Re: Samsung Syncmaster 245BW

Success! Replaced the RB80# resistors with a new trio of 5W 68Ohm ceramic monsters, and display fired right up. I would really like to know what fried the RB805 resistor in the first place, but who can tinker when there is a backlog of work to be done.

Thank you moderators and members for creating such a fantastic resource for DIY electronics resuscitation.

Keith

[jetadm123]

Re: Samsung Syncmaster 245BW

Success! Replaced the RB80# resistors with a new trio of 5W 68Ohm ceramic monsters, and display fired right up. I would really like to know what fried the RB805 resistor in the first place, but who can tinker when there is a backlog of work to be done.

Thank you moderators and members for creating such a fantastic resource for DIY electronics resuscitation.

Keith

Congrats on the repair. I'm surprised that you were able to squeeze in 5W resistors. Since so many people have had problems with RB805, I would suspect that the original 68 ohm resistors barely met design specs at 1 Watt. And over time, constant overheating eventually caused the resistor to break down and fail. I personally would use a resistor rated at 2W as a replacement.

[wolf5]

Re: Samsung Syncmaster 245BW

Replaced the RB508 with a 2W 68Ohm. Same size as the original one. Monitor works!

[ChuckTs]

Re: Samsung Syncmaster 245BW

Hoping to get another success story here, looking for help on what to replace and how. My 245 started clicking, if I remember correctly, kind of quietly for about a week before it went dead. Power still turns on, but the screen is completely black. No gx settings help, almost positive it's internal with the monitor unless I've completely overlooked something. Thank god I normally dual-monitor

Took it apart; here are some 'overview' photos of every board, front and back. I noticed some kind of scum on the back of two of them, but don't see where it's coming from. With my non-existent experience, I didn't notice any busted caps or leaks on the top side of any of the boards. Let me know if you need any part numbers or closer pics or whatever. Also, if/when I get a replacement part, I assume I either need to send it in to get repaired or figure out how to repair it myself - I'll probably need soldering equipment right?

I'm a complete newbie to this so any and all help is much appreciated. Thanks in advance and let me know about anything else I need to post.

EDIT: I tried to upload my pics but got a "there was no security token" error

[PlainBill]

Re: Samsung Syncmaster 245BW

Hoping to get another success story here, looking for help on what to replace and how. My 245 started clicking, if I remember correctly, kind of quietly for about a week before it went dead. Power still turns on, but the screen is completely black. No gx settings help, almost positive it's internal with the monitor unless I've completely overlooked something. Thank god I normally dual-monitor

Took it apart; here are some 'overview' photos of every board, front and back. I noticed some kind of scum on the back of two of them, but don't see where it's coming from. With my non-existent experience, I didn't notice any busted caps or leaks on the top side of any of the boards. Let me know if you need any part numbers or closer pics or whatever. Also, if/when I get a replacement part, I assume I either need to send it in to get repaired or figure out how to repair it myself - I'll probably need soldering equipment right?

I'm a complete newbie to this so any and all help is much appreciated. Thanks in advance and let me know about anything else I need to post.

EDIT: I tried to upload my pics but got a "there was no security token" error

That is probably because they are too large. The maximum dimension allowed is 2000 pixels. I suggest using Vueprint (it's free) to trim them to somewhere in the 1000 x 1000 to 2000 x 2000 range.

PlainBill

[ChuckTs]

Re: Samsung Syncmaster 245BW

Thanks Bill. Resized them but got the same error so I just uploaded to Imgur instead:

http://i.imgur.com/UTrL4.jpg
http://i.imgur.com/leI2n.jpg
http://i.imgur.com/nOocD.jpg
http://i.imgur.com/aoxGh.jpg
http://i.imgur.com/IwYHj.jpg
http://i.imgur.com/DAKwX.jpg

[alexanna]

Re: Samsung Syncmaster 245BW

I have a really nice 10m camera, that takes some awesome pictures but I have to reduce the settings down to around 5m to be able to post pictures here.
So if you have a really high resolution camera try it at about 5m and along with resizing, they should post.

[eagleeyez]

Re: Samsung Syncmaster 245BW

Another succes story by replacing most of Capacitors but The problem was due to CM802 (18nF 630V) bought from this guy in ebay (really great service and fast shipping) :

http://stores.ebay.com/Atlantic-Elec...id=p4340.l2563

You can ask him to ship you only the required amount of parts.

[eagleeyez]

Re: Samsung Syncmaster 245BW

I forgot to thank everyone who participated in this thread the information shared here was really valuable.

I will try to participate more soon

[TQ_uk]

Re: Samsung Syncmaster 245BW

Another massive thank you to everyone on this thread.
One of our office 245B's died the other week & I Googled up this forum.

Despite me being much better at taking things apart than re-assembling them I thought as I'd got nothing to lose, so after following the steps others had taken found resistor RB805 was kaput.
Just replaced it, now all good!

29p replacement saved me spending £hundreds on a new one!

Thanks again

[Atomical]

Re: Samsung Syncmaster 245BW

Just a major thanks for the people who have helped on this post. Sorted my monitor out using the CM802 (18nF 630v) Cap. Put in a slightly higher nF at 21 and all is well

Even changed the 68ohm resistors while I was at it..

Really happy chappy

[wind_watcher]

Re: Samsung Syncmaster 245BW

From opening the "mysterious" plastic case to the varied suggestions and measurements I just wanted to say a BIG thank you. After spending a whole day of reading this substantial thread and poking about my failed monitor power supply board, I too believe to have found the culprit among the RB80x cluster. All three linked in series should be 68ohms each, yet RB805 measured 1740ohms. And since the three in series total 200ohms at 3W, perhaps a nice robust 200ohm 5W single unit may be an improvement.

Thinking on why particularly RB805 seems to fail, perhaps the varied tolerance between the three causes the one with the lowest resitance to carry the larger thermal burden - especially if 3 watts is already marginal. A single fat robust ceramic wirewound 5W is starting to make good sense to me. I'll post again if my monitor fires up again as a result.

[PlainBill]

Re: Samsung Syncmaster 245BW

From opening the "mysterious" plastic case to the varied suggestions and measurements I just wanted to say a BIG thank you. After spending a whole day of reading this substantial thread and poking about my failed monitor power supply board, I too believe to have found the culprit among the RB80x cluster. All three linked in series should be 68ohms each, yet RB805 measured 1740ohms. And since the three in series total 200ohms at 3W, perhaps a nice robust 200ohm 5W single unit may be an improvement.

Thinking on why particularly RB805 seems to fail, perhaps the varied tolerance between the three causes the one with the lowest resitance to carry the larger thermal burden - especially if 3 watts is already marginal. A single fat robust ceramic wirewound 5W is starting to make good sense to me. I'll post again if my monitor fires up again as a result.

Remember ohms law and the formula for calculating power dissipation. In a series string, the resistor with the HIGHEST resistance dissipates the most power.

More likely the prevalence of RB805 is due to position. The resistor with the least cooling air is most likely to fail.

PlainBill

[pegasus5334]

Re: Samsung Syncmaster 245BW

thanks to all the people of this topic for de detailed information about the problem and
solutions.
bleu on/off button blanck screen no OSD nothing i have search a bit on internet and found this forum get my multimeter and yes 3 resistors open loop I spent 50 eurocent by the local
parts store for a 5 x 68 ohm 2 watt resistors and my lcd is lighten up again so thanks folks