Samsung Syncmaster 245BW

[ChuckTs]

Re: Samsung Syncmaster 245BW

Sorry about that, and thanks for attaching them toasty. I'll do it myself when I post pics from my second monitor.

Toasty: I'm a complete newbie to anything under the hood here. Could you specify which is the mains cap? Would that be the giant one? (board says "cp803"; cap says 450WV, 82mF).

I assume that's all I'll be looking for when shopping for replacements too; the working voltage (had to google that) and the capacitance? You guys have a suggested store for someone in Canada?

Thanks so much for the help, this will save my butt.

edit: just found this kit on ebay. Checked to match the appropriate mF levels and it looks like everything matches, except for the largest cap (82mF). Can someone confirm this kit is legit and has everything I need? Thanks again!

[ChuckTs]

Re: Samsung Syncmaster 245BW

...woops, completely forgot the link: http://www.ebay.ca/itm/Repair-Kit-Sa...ht_4491wt_1052

[mr_jrt]

Re: Samsung Syncmaster 245BW

Hi all. Repairing one of these screen for my little brother (screen showing these symptoms), and just checking the resistors before I unsolder the caps (which all look fine visually) for testing. The fuses are fine, RB804, RB805, RB806 all measure 68Ω, so fine there.

I'm a touch confused by the other resistors though, in particular RM802, which I read off as black, grey, green, black, gold. This makes no sense (black as the first band?), so there's clearly something I'm not aware of, and was wondering if someone could shed a little light on things for me. One of the black bands is thinner than the other...but AFAIK, resistors aren't polarised? An alternative reading could be Brown, Black, Green, Silver, giving 1MΩ, but the measurement starts at 0.82MΩ, then veeeeery slowly climbs up to 0.866MΩ.

Incidentally, RM801 measures as 0.7Ω rather than the marked 0.22Ω (Red, Red, Sliver, Gold?), and RX801S measures as 0.718MΩ rather than the marked 0.750MΩ (Violet, Green, Yellow, Silver, Black). I'll leave desoldering and testing the caps until tomorrow I think....

[Toasty]

Re: Samsung Syncmaster 245BW

In circuit a resistor may read less than its marking. The climb you are seeing is likely a capacitor being charged by the ohmmeter.

A resistor will either read right on or darn near and never more. If it reads more, it's bad. Overheating causes them to fail and the resistance always climbs or they go open circuit.

Toast

[mr_jrt]

Re: Samsung Syncmaster 245BW

Cheers, nevermind though....seems when I was trying to get the frame off I've damaged the screen. The only instructions I found said you had to take the screen frame off, so I tried lifting front away from the screen first before discovering the correct way from the rear.

*sigh*

...incidentally, it may have just been dry connector joints as aside from the messed up big white bars with tell tale LCD damage at the top, the picture seemed to work fine when I powered it up after reconnecting everything. All the more annoying, but luckily my bro had written it off before giving it to me to try and salvage. Feeling pretty bad regardless right about now though.

[TQ_uk]

Re: Samsung Syncmaster 245BW

I posted last year having successfully repaired one of our office 245Bs by changing the 805 resistor.
Last week another of our 245B's started flickering when first turned on, finally settling down after about an hour once warm.

I've just taken it apart, checked the 3 'troublesome' resistors, 1 was showing about 95ohms so flush with my success from last time & full of false confidence swapped that one out & reassembled.

No joy, same problem.

I've read through this entire (& similar) threads & from others with similar problems the finger(s) seem to point towards the big 450V/630V capacitors (CP803/CM(QM)802 etc).

I have a soldering iron, a multimeter & not much electronic knowledge, but
happy to have a crack at it.

Can I test the capacitors easily?

Help me Obi-wan(s), you're my only hope, I don't really want to have to turn that monitor on an hour before I need to use it every time....

[Toasty]

Re: Samsung Syncmaster 245BW

See my response to a similar question in another 245 thread:
https://www.badcaps.net/forum/showpo...0&postcount=29

I believe there was mention (alexanna?) that the mains cap is a source of problems, so replacing that is a very good idea. But just doing one cap, is not so good. That is unless you enjoy taking them apart again and again until you've finally replaced all of them anyway....

Toast

[TQ_uk]

Re: Samsung Syncmaster 245BW

Hmmm, not really...!

Thanks for swift reply, I'm going to pull monitor apart again to see if there's any obvious bulging caps etc that I missed before it my flush of enthusiastic resistor replacement!

Was hoping I could do an easy test with a multimeter to diagnose any bad caps but I guess not....

[TQ_uk]

Re: Samsung Syncmaster 245BW

Ok, quick update for any poor souls with similar problems.

Pulled monitor apart again & main cap CP803 had a bit of a bulge, don't have suitable testing equipment & didn't fancy prodding around the PCB with the power on, so for £4 got a replacement, just put it in & monitor's now been up & running fine for last few hours.

Hurrah

Thanks again for everyone's advice

[impala454]

Re: Samsung Syncmaster 245BW

So a few months ago I replaced the three "evil" resistors and fixed my monitor. Now I'm back with the flickering issue. It flickers and then the flicker slows down as I turn the brightness down, and the flickering essentially stops completely once I get to zero brightness. After thumbing back through the thread it seems like a cap issue. I've got it torn apart again and upon thorough inspection I don't see any blatantly obvious dead caps. I realize "just recap the whole board" is the standard answer but call me a glutton for punishment in that I only like to replace the bad parts. The main cap is domed slightly but not sure how much give it should have. All the rest of the caps appear completely flat on top, but that could just be my untrained eye.

[jetadm123]

Re: Samsung Syncmaster 245BW

So a few months ago I replaced the three "evil" resistors and fixed my monitor. Now I'm back with the flickering issue. It flickers and then the flicker slows down as I turn the brightness down, and the flickering essentially stops completely once I get to zero brightness. After thumbing back through the thread it seems like a cap issue. I've got it torn apart again and upon thorough inspection I don't see any blatantly obvious dead caps. I realize "just recap the whole board" is the standard answer but call me a glutton for punishment in that I only like to replace the bad parts. The main cap is domed slightly but not sure how much give it should have. All the rest of the caps appear completely flat on top, but that could just be my untrained eye.

The main reason people are told to replace all the caps is because most people who seek help here don't have a scope or esr meter to help them troubleshoot bad caps. Besides, it doesn't make sense to replace only a portion of the caps. If the original caps are a crap brand, then it's only logical to replace them all. Asking members to spend time to try and pinpoint which cap(s) is/are bad in order to save a few dollars is a total waste of eveyone's time.

[impala454]

Re: Samsung Syncmaster 245BW

Well I'd hate to waste 30 seconds of someone's time looking at the image vs several hours of my own time replacing every cap. That said, I posted the image more so to see if there was something I was missing that perhaps a person with more knowledge might see. And that said, I went ahead and ordered the full kit anyways. I appreciate how helpful this site has been. Will report back once I get it all done!

[Toasty]

Re: Samsung Syncmaster 245BW

Tough to tell the "doming" of the mains cap with a top down shot. The plastic insulator top gives a false indication of doming because of the capacitor wrap which pulls its edges in.

Also, the mains don't usually dome or leak as the smaller caps do. They just dry out or lose capacitance and -can- be -a- cause of the flickering.

Perfect looking caps can be (and often are) bad.

I don't believe the full kit includes the mains cap, does it?

Toast

[impala454]

Re: Samsung Syncmaster 245BW

Naw the kit didn't include the mains, I figured I'd just get it separately if need be later. Thanks!

[TQ_uk]

Re: Samsung Syncmaster 245BW

My main cap was same as yours (Samwha) and definitely wasn't totally flat so I suspected that. Replaced it, all good so far.
I know its a bit of a hit & miss approach, but my soldering skills leave something to be desired (I blame the tools!) so didn't relish the thought of recapping entire board.
Guess I got lucky (so far) plus main cap was under £4 so not too much of a gamble...

[impala454]

Re: Samsung Syncmaster 245BW

Is there a good purchase link somewhere for the mains cap?

[Toasty]

Re: Samsung Syncmaster 245BW

If you would fill out your profile with your location, it might help...

[impala454]

Re: Samsung Syncmaster 245BW

I'm in Texas... just need somewhere to order online unless you think radio shack or fry's would carry that exact cap.

[jayoung]

Re: Samsung Syncmaster 245BW

I order all of mine from digikey.com. They have an option for USPS first class mail that is usually just a few dollars and arrives within a few days.

If you post the capacitance, voltage, diameter, height, manufacturer and series, someone on here can help in finding a suitable replacement, if needed.

[TQ_uk]

Re: Samsung Syncmaster 245BW

For any UK based people looking I got mine from:

RS Components