Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

[OberAgain]

Heya Badcaps!

Fixed my last BW245 with the help of this forum, but now its been a few years and the second of my three BW245's has died, last one i fixed after some help with a full round of cap/resistor replacements on the power board... its been SO long and with no practice i dont remember how to do some of the tests and this one has different problems than my last...

At the moment the monitor only turns on randomly like once a month or less, if i turn it off while its hot i can sometimes get it to turn right back on but the only times ive tried that was because it was Flickering so badly i could not even ignore it without an image on it, bright images flickered more obviously...

So im assuming i have a problem with the power board lol -- i guess it could be with the lights/inverter board....

68 ohm resistors tested as 67.1 67.2 67.7 ...tho ill replace them anyways with other parts

the double white tube fuses on power board and the fuse on inverter started around 057 down to 001-000 with continuity test...

That is as far as ive gone with the project, two of the SamWha Caps (CB809 & CB876) are seemingly bulging at the top, slight slant upwards, the same two that were bulging on the last 245bw that selldoor basically fixed with my hands lol... so i dont know if thats normal bulge or not but when i said that last time i was reminded that no bulge is normal so i guess those could be a problem but no ESR meter....

Also yes, i just cleaned off the gunk/glue -- if i chipped a bit of the resistor's color off and can see the silver inside a little is that piece now bad? lil about mm sq piece broke off...

[R_J]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

I would start by replacing these 2 caps. they both look bulged. and are most likley bad.

[OberAgain]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

Yea thats CB809 and CB876 i mentioned bulging above.... Is it likely that those caps could be the cause of a flicker screen? i plan to replace all the caps and resistors but i guess i wanted to know if that would be a likely cause with the symptoms i mentioned or if it is likely to be something like the bulbs or maybe one of the other boards?
Thank you much!
Ober

[Lumberjack777]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

Those 2 caps could definitely cause a flicker. Especially the symptom "if i turn it off while its hot i can sometimes get it to turn right back on" because even bad caps have a lower ESR when they are warm.

[R_J]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

You could try replacing the 2 caps, It might just fix the problem invest the $1.00

[OberAgain]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

Its not as much the $1.00 as the idea of having to order it all and wait for the parts lol, if i could go down to a store and grab them i would have done it already...

I had just put together my list of caps and resistors (figuring out the resistor ratings now, some are pretty tough to see)

You really suggest only changing out those 2? (guess i could use radio shack parts to do that?) everything else i read says invest the few more $$ buy quality parts and change the rest as they will go out sooner or later anyways and taking it apart and ordering are the worst parts?

Thanks for Input!

[budm]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

"68 ohm resistors tested as 67.1 67.2 67.7 ...tho ill replace them anyways with other parts"
Resistors are fine, the bad one will show open circuit or very high resistance.
Check the capacitance of the cap in red.
You MUST also remove ALL those yellow glues that turned dark brown, they are conductive and corrosive, especially around the high voltage sections otherwise you will have more damages:
https://www.badcaps.net/forum/showthread.php?t=34692

[OberAgain]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

Tried to find info how to do capacitance test and i couldn't find the setting on my multimeter that was being suggested, one of them showed the Continuity symbol reversed on the same setting so i tried that, result was 541 -- was that the correct way to test?

Glue ive been working on sense first post, broke a chip of ceramic off a resistor trying to remove some making ~1mm sq of silver core visible, assuming that needs replacement? some of that glue is just impossible to remove, im tryin to soften/work it with ISO, the darker stuff is easier to get off (very brittle) and the more yellow stuff is pretty much impossible to remove without destroying the components...

Thank you

[budm]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

Cap has to be removed from the board to test the capacitance, per diagram it is supposed o be 0.018uF (18nF). This cap is for the 24VDC and 5.3VDC power supply section.
BTW:
Is the 5V Standby steady?
Is the 24VDC output feeding the Inverter board steady?
Are the filter caps on the inverter board OK?

[OberAgain]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

Would need instruction to know how to check those, under the assumption i need to reconnect everything and plug into power and source to test the 5v and 24VDC?

Filter caps on inverter board visually look ok (white glob of glue does make the tops hard to see but what i can see looks fine) -- if you mean by testing, please advise how to do the tests...

Is continuity the right setting to test capacitance?

DMM Model: DT-830B (Picture/Info of DMM) http://www.papou.byethost9.com/DT830/

[budm]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

"Would need instruction to know how to check those, under the assumption i need to reconnect everything and plug into power and source to test the 5v and 24VDC?" The 5V standby power supply is always present, the 24V and the 5.3V is turned on when power switch is activated. You have to have the cable between the main board and the main board connected.
"Is continuity the right setting to test capacitance? " No.
Your meter does not have capacitance testing function.

[OberAgain]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

between logic board and power board? not quite sure which two main boards your referring to... still need instruction from there as well, i dont know where to test, is this the test where i put one probe on ground and the other on the pegs to the ribbon cable? (even if so, which ribbon cable am i checking? none of them list both 24v and 5v, several of either but none with both, one has 5v and power?

Sorry, for my lack of knowledge - the only thing im running on was fixing one of these about two and a half years ago, ive been rereading my own previous thread to try to understand but its been so long...Go figure both had the same caps bulging in them...

[budm]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

you better show the pictures of the boards and how they are connected together then.

[OberAgain]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

Here is picture of layout, ribbon going down off the board on right connects to LCD screen just behind where the power board sits

If i have the correct idea,
Inverter board - Power Board - Logic Board > LCD

[budm]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

"Inverter board - Power Board - Logic Board > LCD" That is correct, you do not need to have the cable (LVDS cable) from the Logic (main board) connected to the LCD panel for testing. The cable between the Inverter board and the power supply can also be left out for now. We just want to make sure we have all the correct Voltages at the connectors. You do need the switch board connected and a running pc with VGA cable connected otherwise the monitor will stay in standby mode.

[OberAgain]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

OK Well, i finally got a system setup where i could reach everything to the source/power/ect and still have access to the circuits. Go figure the first time i went to turn it power to on, it lit up lol, it can do that when cold enough...


with the power switch off, basically everything i checked read 0 (if theres a specific that shouldnt, let me know and i can check it again...)

turned power on w/ no backlight shining and i got (THEN noticed i forgot to plug source in - so if it needs source then let me know and ill retest but it had everything but the DVI plugged in)

1 24v 24
2 ""
3 ""
4 ""
5 ""
6 Ground 0.0
7 ""
8 ""
9 ""
10 ""
11 SOS 3.6
12 BL 0
13 A_Dim 0
14 ST_Dim 0


1 PSON 3.0
2 SB 4.3
3 GND 0
4 GND 0
5 GND 0
6 NC 0
7 NC 0
8 NC 0
9 GND 0
10 GND 0
11 GND 0
12 5.3 5.3
13 5.3 5.3
14 5.3 5.3
15 NC 0
16 NC 0


Ribbon next to 5.3v (other three pins were 0)
ST/P-DIMM 5.2
SOS 3.6


Took me awhile but got it done lol... Found another video where someone was explaining how to fix, same exact 2 caps bulging, that's the fourth 245bw ive seen where the only problem when opened was those 2 caps now...

Is there really much more point in testing much more? or should i just be doing a full round of Caps and the 3x 68ohm resistor change out?

Also Video i saw suggested swapping the 10v caps that bulged with 25v of same uF - is this suggested atall? the other one i fixed i put the exact same caps of was was suggested to be high quality parts and its made it another ~2.5 years now sense repair... wasnt sure if higher voltage would be better or more stressful on the rest of the parts ect...

Thank you much!!!
..Ober

[OberAgain]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

was this what was expected? sorry, i know it took me awhile to do it, donno if I got overlooked when i finally got it done...

[R_J]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

There is no problem using 25v caps. they can handle a bit more voltage if required but don't put any stress on anything. the 25volt caps may be slightly larger so they may not fit in some situations. but will be fine here. you could also use 16volt caps if you wanted. If you want to replace the 3 68Ω resistors go ahead. and clean off that brown glue as suggested.
I take it the monitor is working with those caps replaced?

[OberAgain]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

i havent made order yet, this was result to test.... one person said to only change those 2 caps, others have suggested to always change them all... im assuming changing them all would be smart while its apart and its cheap, i did it for the other monitor afterall... mostly wanted to make sure the problem atleast lie within those parts not something else like the bulbs or inverter board stuff...
Going to make order now - hopefully ill get the parts and have it done this coming week
My assumptions are that its just those 2 caps with how it still nearly works, it does still turn on once in awhile just flickers ect.

Highly appreciate the help and had fun relearning some of the testing stuff and cant wait to get to do some board work...

Might need my order looked over when i get it put together - will probably have parts out of stock that ill have to substitute like every time i order from digikey and im never sure im getting exactly the right substitute...will try ot get that posted on here this weekend

Thanks again!

[OberAgain]

Re: Samsung Syncmaster BW245 - Flickers when on, normally wont turn on, no blue light

Sooo, Had been sick then family was in hospital then i was in hospital yadda yadda ect... Finally got the parts and had a moment to work on project but i made a Big Boo Boo that i am not so sure i can fix... in one picture you can see where i accidentally ripped up the pad and my solder sucker just sucked that baby right up and into the bulb - now im not sure if i can fix this or not - Conductive pen i had was already rock hard (never even got to use the damn thing, didnt know it hardened if stored) and $25 for replacement at radio shack - whole board can be replaced for something like ~$65 so not sure if 25 to see if i didnt screw up elsewhere is alot... i changed ALL the caps/resistors on the board already and this area was the only major problem i ran into, the opposite lead to the one i ripped off is also slightly ripped up but its soldered to and still connected so i hope that one is alright...

Also in the other picture, accidentally scratched across the black line/bar that goes around the edge of the board, not sure if it is part of the ground and if i have to do anything about it or if i can just ignore it...

Thanks again for all the awesome help i get around here! Appreciated!
...Obes