Samsung Syncmaster 245BW

[nordhaus]

Re: Samsung Syncmaster 245BW

Thanks for the iron recommendations! Hakko on order (was always wanting a new soldering iron, and this is my excuse!).

So, would 60/40 (tin/lead) .032 diameter rosin core solder suffice for this job?

N~

[Denbo]

Re: Samsung Syncmaster 245BW

Interesting...first time I've heard of the BN96-04024A used on a 245B. Also, good work on troubleshooting. It's not often a shunt regulator fails.

My Bad, the power supply part number should be BN96-04034A, not BN96-04024A.
The backend is of this supply reused the design of the 245B, 24 volts, 5.4 volts, and 5 standby.
I noted it on this thread, in case someone else with this samsung LS20EDBEB/XAA , will have a starting point.
samsungparts.com lists this supply at $97.00. And it cost me $3 to repair.

[retiredcaps]

Re: Samsung Syncmaster 245BW

So, would 60/40 (tin/lead) .032 diameter rosin core solder suffice for this job?

Yes, good old 60/40 with rosin core. BTW, this model is also notorious for 3 failed resistors on the power board.

[nordhaus]

Re: Samsung Syncmaster 245BW

BTW, this model is also notorious for 3 failed resistors on the power board.

Stupid question time - I know about the polarity for Capacitors, but is there such a thing for the resistors?

Do the resistors have to be installed in a certain direction/orientation, or does it not matter?

And if yes, how do I tell which side is which (for the resistors)?

Thanks!

N~

[retiredcaps]

Re: Samsung Syncmaster 245BW

Stupid question time - I know about the polarity for Capacitors, but is there such a thing for the resistors?

No polarity for resistors.

[nordhaus]

Re: Samsung Syncmaster 245BW

No polarity for resistors.

Thank you!

[nordhaus]

Re: Samsung Syncmaster 245BW

Hi,

I notice that the 3 resistors on my board have some kind of brown paste or adhesive on them that "holds" them together. (photo attached).



Three questions for you all:

1) Is this important to replicate (the adhesive) when I put the new resistors in? If yes, what do I use?

2) And, just for grins, I've also attached a photo of the power board - the capacitors look remarkably clean to my eye, anyway. Anyone disagree?



3) Lastly, I want to check the two fuses, but they both appear solid white and don't look blackened in any way. What's the best way to test them?


Thanks!

N~

[jetadm123]

Re: Samsung Syncmaster 245BW

Hi,

I notice that the 3 resistors on my board have some kind of brown paste or adhesive on them that "holds" them together. (photo attached).


Three questions for you all:

1) Is this important to replicate (the adhesive) when I put the new resistors in? If yes, what do I use?



2) And, just for grins, I've also attached a photo of the power board - the capacitors look remarkably clean to my eye, anyway. Anyone disagree?


3) Lastly, I want to check the two fuses, but they both appear solid white and don't look blackened in any way. What's the best way to test them?

Set your meter to 20 ohms resistance setting. With power off, place your probes at each end. A reading of approx 0 ohms indicates a good fuse.
Thanks!

N~

1) No. The adhesive is used to hold the resistors in place during the assembly process. It should be removed as it can become conductive as it dries out over time. Before you go replacing the resistors, take a resistance reading. Each one should read approx. 68 ohms.

2) You cannot tell if a cap is good/bad by just looking at it. A ESR meter will provide that info.

3) Set your meter to 20 ohms resistance setting. With power off, place your probes at each end of the fuse. A reading of approx 0 ohms indicates a good fuse.

[selldoor]

Re: Samsung Syncmaster 245BW

I dont know about "for grins" but posting pictures of the front and back of your power supply and main/video/logic board is almost mandatory and they should be as clear as this one https://www.badcaps.net/forum/attach...1&d=1290283049

As retired caps said earlier


If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here.

Please do not post inline and offsite as they slow down the loading of pages.

[retiredcaps]

Re: Samsung Syncmaster 245BW

I've got the issue on my 245BW where my power button lights up, but no picture on the screen (totally black).

Post a picture of the backside of the power board.

No backlight could indicated an open fuse in the inverter section or shorted mosfets.

[nordhaus]

Re: Samsung Syncmaster 245BW

If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here.

Please do not post inline and offsite as they slow down the loading of pages.

Hi,

I DID use the "Manage Attachments" function and uploaded the photos to the board (hosted). The photos are hosted on the forum.

Secondly, my photos were each 4mb large in origin, so I had to cut them down a bit to meet the guidelines (which I DID READ).

Perhaps, you could give advice on what guidelines I DID miss? And I'd be happy to correct.

Thanks,

N~


P.S. If you click on the thumbnails I posted above, they will show the full size photo I took.

[nordhaus]

Re: Samsung Syncmaster 245BW

Hi,

Ok, per retiredcaps request, here is a photo (again, done by "manage attachments") of the bottom of the power board.

Please note that I've already removed the 3 resistors so don't mind the empty holes.

And while I have the sunlight, I took another photo of the top of the board, and tried to max out the photo in Photoshop, so here it is again (note again, the resistors are missing, as I just removed them).

Thank you!

N~

[nordhaus]

Re: Samsung Syncmaster 245BW

As a side note, I ran the multimeter on the 3 resistors I removed. 2 of them measured .068 and one of them measured .076.

I'm assuming that the variance might indicate an issue since all 3 resistors are the same.

(I'm a novice at reading and using the multimeter, so be gentle).


N~

[jetadm123]

Re: Samsung Syncmaster 245BW

As a side note, I ran the multimeter on the 3 resistors I removed. 2 of them measured .068 and one of them measured .076.

I'm assuming that the variance might indicate an issue since all 3 resistors are the same.

(I'm a novice at reading and using the multimeter, so be gentle).


N~

Here's my suggestion:

The original resistors are 68 ohm 1/2 Watt 5% tolerance. Since one is reading 76 ohms, it's out of spec. The dried glue covering them probably also didn't help. Ideally, I would recommend 1 Watt replacements, but in the interest of time/testing I suggest you go to your nearby Radio Shack and purchase a pack of 5 68 ohm 1/2 W resistors. Should set you back $1.19. Also, pick up some 60/40 solder if you haven't already done so. Solder the new resistors in and see what happens.

[retiredcaps]

Re: Samsung Syncmaster 245BW

Ok, per retiredcaps request, here is a photo (again, done by "manage attachments") of the bottom of the power board.

Okay, those are excellent pics. The reason we are picky about clear focused top down pictures is because doing remote troubleshooting without them is almost impossible. Pictures at an angle or out of focus makes troubleshooting and spotting problems difficult.

We need another set of pictures of your inverter board. This is the board where all the ccfls plug into. On that board is likely one SMD fuse and several mosfets. If the fuse is open or the mosfets are shorted, then you would get no backlight.

See fuse and mosfet testing at

https://www.badcaps.net/forum/showpo...4&postcount=19

[PaFromFL]

Re: Samsung Syncmaster 245BW

...After reading through posts about the burned out resistor RB805, I checked mine, and it was dead open. It did not show visible signs of burns or charring, but it was dead nonetheless...

My son's monitor had the same problem. I replaced RB805 with a large 50 year old 68 ohm wirewound resistor. Fortunately there was plenty of room for it to stick out beyond the edge of the circuit board. I never would have found the problem without this forum. Many thanks for the advice!

[nordhaus]

Re: Samsung Syncmaster 245BW

Update: Ok, I replaced the 3 "usual suspect" resistors on my 245BW Power board (RB805, RB806, RB807), but no joy. Monitor still doesn't light up (blue light on power button remains lit, as before).

So I've moved on to replacing the 14 capacitors on my power board (except for the big 850V capacitor).

Will take a photo of the Inverter board when I get up in the morning.

Thanks!

N~

[selldoor]

Re: Samsung Syncmaster 245BW

Hi - sorry about the photo mix-up I am still 99% certain that the pictures were not there when I made my post.
I usually look them over while I am considering what the poster has said.
Whilst that may seem incredible and I cannot prove, it If you look at the Quote in post 468 by jetadmin 123 the links to the pics are not there (perhaps he deleted them)

Anyway, they are there now and they are excellent.

Suggest you remove the glue from other components if it touches conductive parts - near cp810 and DB801

There is also another fuse on this board you can test at FB802S just about dead centre of the board.
"(except for the big 850V capacitor)" should probably read 450V

[jetadm123]

Re: Samsung Syncmaster 245BW

Update: Ok, I replaced the 3 "usual suspect" resistors on my 245BW Power board (RB805, RB806, RB807), but no joy. Monitor still doesn't light up (blue light on power button remains lit, as before).

So I've moved on to replacing the 14 capacitors on my power board (except for the big 850V capacitor).

Will take a photo of the Inverter board when I get up in the morning.

Thanks!

N~

Okay, replacing the resistors was a step in the right direction. If you have verified that you're not getting the 24V output, which powers the inverter board, then the second most common failure of this board is capacitor CM802. It's rated at 18nf 650V.

[nordhaus]

Re: Samsung Syncmaster 245BW

Okay, replacing the resistors was a step in the right direction. If you have verified that you're not getting the 24V output, which powers the inverter board, then the second most common failure of this board is capacitor CM802. It's rated at 18nf 650V.

Ok, stupid question time again......How and where do you measure for 24V?

I've done a search and theres plenty of references to 24V output (or lack thereof), but can't find any pointers or how-to style posts.

I do have a multimeter, so I can do it, if there is a how-to I am missing somewhere.

Thanks!

N~


P.S. CM802 looks like a square blue chiclet, and not like a traditional capacitor. Is that the one? The rating I read on it is also 18nf 630V, not 650.