Samsung Syncmaster 245BW

[jetadm123]

Originally Posted by nordhaus

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~

In the upper right of your power supply photo there is a white connector. This connector connects to your inverter. Correct? There looks to be 24V silkscreened on the board below the connector. Reconnect the logic board, power supply and inverter. Set your meter to 200V DC. Apply power. Place your neg probe on a mounting screw and your pos probe on one of the 24V pins of the connector. Are you seeing 24V?

[nordhaus]

Originally Posted by jetadm123

In the upper right of your power supply photo there is a white connector. This connector connects to your inverter. Correct? There looks to be 24V silkscreened on the board below the connector. Reconnect the logic board, power supply and inverter. Set your meter to 200V DC. Apply power. Place your neg probe on a mounting screw and your pos probe on one of the 24V pins of the connector. Are you seeing 24V?

Note: I did replace all 14 of my capacitors (not the big 850V one). Also replaced all of the three troublesome RB resistors.

Thanks for the tips jetadm123!

I reconnected logic board, power board and inverter. Reading 0 on all 24V pins. No joy.

Wow........what next? 850V capacitor?


N~

[nordhaus]

Hi,

Ok, here are the photos of the Inverter board, per RetiredCaps request.

I don't see any 3-pin mosfets on this, but there were 4 mosfet-like items that had 4 pins. I tried testing them on the multimeter in various pin configurations, but got no readings.

Regarding fuses, I did see a small item that could be a micro fuse (very tiny, copper looking ends, small white body), near the connector pin.

Tested it on the multimeter and got a 0.2 ohm reading, indicating that the fuse is ok, right?


Thanks!

N~

[nordhaus]

Originally Posted by selldoor

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.

- Glue removed. Nasty stuff, that red glue.

- I saw a red rectangular block there (photo attached). Didn't look like a fuse, but I turned the board over and tested with the multimeter.....got a 0.2 ohm reading, which should be ok, right?


Thanks for your help!

N~

[nordhaus]

Originally Posted by jetadm123

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.

Here is a photo of the CM802 I could find (the blue chiclet). It looks to be marked 630V.

Is this the one? Doesn't look like a regular capacitor.........and where would I get this one?


Thanks!

N

[retiredcaps]

Originally Posted by nordhaus

Here is a photo of the CM802 I could find (the blue chiclet). It looks to be marked 630V.

Is this the one? Doesn't look like a regular capacitor.........and where would I get this one?

See (where I get schooled by PlainBill )

http://www.badcaps.net/forum/showthr...ighlight=CM802

[selldoor]

@ retiredcaps -As you mention PB -do you know where he is, another MIA? although his profile says last contact 3 April im sure its been weeks- Away for birthday? Hawaii?

[retiredcaps]

Originally Posted by selldoor

@ retiredcaps -As you mention PB -do you know where he is, another MIA? although his profile says last contact 3 April im sure its been weeks- Away for birthday? Hawaii?

Not to drag this off topic, but this was the last post I remember from him (March 3).

His comment regarding budm below leads me to believe he might be taking some time well deserved time off?

http://www.badcaps.net/forum/showpos...6&postcount=12

"You are making a large number of pictures available and directly helping many people here. That is a very good thing, and I can now take a half day away from the forum without feeling guilty. Thank You!!"

[nordhaus]

Update:

Just ordered the CM802 and also the large 450V large capacitor (just in case) from Digikey.

Will update again when I get the goods and install them.

But I still have questions -

1) For these two capacitors, I looked at the backside of the board. Unlike the other smaller capacitors, the solder point looks different. The Capacitor wire seems to be ringed by 5 tiny prongs in the solder - is there some different sort of mounting/soldering system going on for these "heavier duty" capacitors? Anything I need to look out for?

2) Is it necessary to reconnect everything (powerboard, logic board, inverter board, etc) to test for 24V? Couldn't I just plug the power cord into the unconnected power board and turn the power switch on? Or is it a safety issue?


Thanks!

N~

[selldoor]

1 - As you guess its just a heavier carrier for the heavier capacitors - nothing to worry
about - may need pre heating a bit to unsolder if you have to do it.

2 - My understanding is that most boards start off with a low voltage which goes to the logic board which carries out various tests then sends a signal back to the power board via pin PS-on which starts up the higher voltages to drive the inverter/ back lights.
Some boards see not having the whole thing connected as a fault and will not start and
I have read other members saying that starting the inverter board without the panel puts
pressure on that. I am sure there are longer explanations on the forum Budm will probably have done a guide if you can find it.
So you can plug it in and test quickly and if its there great! then switch off, but if it isnt it may be because of the above.

[retiredcaps]

Originally Posted by nordhaus

2) Is it necessary to reconnect everything (powerboard, logic board, inverter board, etc) to test for 24V? Couldn't I just plug the power cord into the unconnected power board and turn the power switch on? Or is it a safety issue?

Connect everything together.

The main board tells the power supply to turn on secondary voltages (like 24V DC). No main board = no 24V DC.

[nordhaus]

Thanks for that.

One more question.......two of the new capacitors are touching each other (they have a brand new coating). One of the caps is a bit larger than the one it replaced, and thus, in a crowded area, it is unavoidable that they are touching. Is this a really bad thing?

Thanks!

N~

[retiredcaps]

Originally Posted by nordhaus

One more question.......two of the new capacitors are touching each other (they have a brand new coating).

As long as the legs of the capacitors are not touching, it is fine.

[nordhaus]

Hi,

Ok, so I got the CM802 Replacement from Digikey (a part referenced by PlainBill in another part of the thread) here:

http://search.digikey.com/us/en/prod...550-ND/2567798

It is a Panasonic part, but looks quite a bit smaller than the blue chiclet cap it is replacing. The other issue is that there appear to be no polarity markings on this new one, nor on the blue original (both pictured), nor on the board itself.

The photo of my new cap (reddish brown) only has text on one side, and no other markings, and the wire legs are both the same length.

I'm assuming for this particular kind of Cap, polarity does NOT matter?

Thanks!

N~

[jetadm123]

Originally Posted by nordhaus

Hi,

Ok, so I got the CM802 Replacement from Digikey (a part referenced by PlainBill in another part of the thread) here:

http://search.digikey.com/us/en/prod...550-ND/2567798

It is a Panasonic part, but looks quite a bit smaller than the blue chiclet cap it is replacing. The other issue is that there appear to be no polarity markings on this new one, nor on the blue original (both pictured), nor on the board itself.

The photo of my new cap (reddish brown) only has text on one side, and no other markings, and the wire legs are both the same length.

I'm assuming for this particular kind of Cap, polarity does NOT matter?

Thanks!

N~

Correct. Polarity does not matter.

[nordhaus]

Hi Guys,

Just wanted to give you a big thank you to all - I swapped out the CM802 capacitor, and BAM, got 24 volt readings on all 5 24-volt pins near the plug. Checked the monitor screen and got an image!

The monitor is working great now, and the image even seems a bit better! I was having some streaking near the top of the screen (it matched the corners of my windows and browser tabs, so I assumed it was an early burn-in), but now, all the streak marks are gone too!

Special thanks to jetadm123 and selldoor for their kind tips. And exceptional thanks to retiredcaps, who hung in there with me through all the dumb questions I asked!

I'll follow this post up with some tool tips that helped me out - hopefully another newbie like me who comes here will find it useful.

Thanks again! I have another 245BW monitor, and yet another similar 245T monitor on another computer, so all of this "training" will come in extremely handy down the road, I'm sure! Not to mention the fact that I was able to acquire some cool new tools and gadgets with the wife's approval!

Many thanks!

N~

[nordhaus]

Hi,

I was able to successfully able to repair my Samsung 245BW monitor recently. I replaced nearly all of the capacitors, replaced the problematic RM805, RM806, and RM807 resistors, and finally replaced the CM802 capacitor - all on the monitor's power board.

I've only had limited experience soldering, and even less so on any kind of circuit board. I made some mistakes along the way, and learned a few things, especially about the tools to use.

Here are some of the tool lessons I learned:

1) Taking the rear plastic panel off the monitor is a challenge, as the panel is "snapped" in via plastic tabs. I ended up using a set of nylon-style pry bars that I found at Harbor Freight (a U.S. tool chain that specializes in low cost tools). These nylon pry bars are mainly for use by the automotive trade (stereo installers, especially) to pry off and remove door panels on cars. They worked fantastically to pop the tabs on the monitor panel, and also acted as wedges while I worked my way around the back panel popping more tabs. I had absolutely no damage to the panel. (tool photo attached).

They run a mere $5.99, and can also be ordered online.

http://www.harborfreight.com/4-piece...kit-95214.html


2) When I first started trying to remove capacitors and resistors I tried using a solder wick to soak up the solder - it didn't work that well. Then I picked up a cheap "solder sucker" that worked better, but was far from ideal. Then I ran across a larger solder sucker tool from Edsyn Soldapullt and bought it. It worked GREAT. (photo attached).

Runs about $20 on Amazon, but can also be found on Ebay too. Lots of positive reviews.

http://www.amazon.com/Edsyn-Deluxe-S...4465565&sr=8-3


3) In order to cut the excess wire legs from capacitors and resistors, you'll need a small wire cutter that can cut flush to your solder point. I bought a Cresent Miniature Wire Cutter and Miniature Plier set from Home Depot. The pliers came in very handy to compress and remove the plastic tabs on the plastic shielding covering the power board. As I recall, the price was about $12-$14. (photo attached)

You can find these type of wire cutters and pliers all over, from a small electronic store, to Home Depot or Lowes, to Radio Shack. Amazon and Ebay too.


4) Early on, I decided to "re-cap" the entire power board (except for the largest "main" capacitor - the big black one). I found a seller on Ebay that sold the entire set of capacitors as a kit for the 245BW. I think this seller was also mentioned in this thread as well. They only sell items from Panasonic, Nichicon and Rubycon - brands that seem to be mentioned often in here. The kit also includes the problematic 3 resistors (RM805, RM806, and RM807).

I'd link to the auction, but over time it will go away, so here's a link to the seller instead:

http://stores.ebay.com/LCDALTERNATIVES

Do a search for "Samsung 245BW" from inside his eBay store, and you'll find the kit.

Note, my kit included an extra capacitor - according to the seller, some versions of the 245BW power board do have an extra capacitor. So if you're replacing the caps, and come up with an extra one, don't panic.

If you go to their website, they also have many useful generic videos on how to solder a capacitor, how to remove a capacitor, and so on. Go watch them.

http://www.lcdalternatives.com/


5) I've got a 15 year old Radio Shack-style soldering iron, and for this job, I wanted something better, a big-boy Soldering Iron kit. Member retiredcaps recommended that I look at the Hakko FX-888 Soldering Station (I was previously about to buy the Weller Station).

Very, very pleased with the Hakko...........it can provide enough wattage/heat to punch through the solder even for the larger capacitors.

It isn't cheap (about $85), but it does go on sale........Amazon carries it, as do many other stores.




Tip: If you're a newbie like me, or a bit rusty, practice your soldering. If you have a broken piece of electronic gear with a circuit board, practice on that. If you don't have anything, go to your electronics store or Radio Shack and pick up a small blank circuit board and a couple of cheap resistors or capacitors (should be under $2 for everything). You can practice setting and removing capacitors and sharpen up your soldering technique with the gear you have.


Hope this helps you! There are LOTS of friendly, helpful people here, so ask questions! I learned a lot from the senior members of this forum, and even more by just reading through this entire thread.

Thanks again everyone! Your help has been so valuable, and has given me high confidence should I face monitor problems again!




N~

[Jasgriff]

Glad to hear you got your monitor going. Also thank you very much for taking the time to write your last post and explaining your learnings that will definately help people in the future.

[selldoor]

Well done Nordhaus! This thread will be a useful tool for others in future and your summary is great - wish other would do that - some dont even report whether its fixed or not and the thread just dries up.
Thank you.

[retiredcaps]

Originally Posted by nordhaus

Here are some of the tool lessons I learned:

1) I ended up using a set of nylon-style pry bars that I found at Harbor Freight (a U.S. tool chain that specializes in low cost tools).

They run a mere $5.99, and can also be ordered online.

2) Then I ran across a larger solder sucker tool from Edsyn Soldapullt and bought it. It worked GREAT. (photo attached).

Runs about $20 on Amazon, but can also be found on Ebay too. Lots of positive reviews.

3) As I recall, the price was about $12-$14. (photo attached)

4) I found a seller on Ebay that sold the entire set of capacitors as a kit for the 245BW.

5) I've got a 15 year old Radio Shack-style soldering iron, and for this job, I wanted something better, a big-boy Soldering Iron kit.

Well, for post #500 , I will present the lowest possible cost way of getting the monitor fixed. These are my real life tools that I started with almost 2 years ago and still mostly use today.

Obviously, good tools makes the job much easier and last longer, but for a one time DIY fix, these will suffice as well.

1) The old butter knife. Yes, it might scratch, scar the plastic and break a few tabs, but it works.

2) Sewing kit (free from some hotel). I used the stainless steel bobby pin to clear the holes after removing the capacitor. I used to use a solder sucker, but the bobby pin works way better.

3) Dollar store wire cutter. I think I got this at the dollar store back when all items were actually $1 and not $1.25 or $1.50.

4) If you live in the USA, a DIY capacitor order through digikey.com will save you about 50% or more the cost versus the kits found on ebay.

5) Sort by lowest ebay price 40W (around $4 USD) soldering iron. These irons work, but they come with a conical tip which has less thermal transfer area than a chisel tip. It is almost impossible to find a cheap 40W iron with a chisel tip and replacement tips are non existant so consider this a disposable iron after the tip dies.

5a) Stainless steel scour pad. I used to use a wet sponge to clean off the solder iron tip, but I find the scour pad works just as well with no thermal shock. $2 for 3 at Wal-Mart or equivalent.

6) Nordhaus never mentioned his multimeter, but I made the foolish mistake of buying your 99 cent cheap crap multimeter off ebay when I first started. I have long since fixed that problem by buying several good used Fluke brand multimeters. You can always borrow one from a friend or get yourself a decent one as it is a handy tool to have around the house.