Samsung 245bw No Power No LED

[Ober]

Directly plugged into wall, Switch to on (and ofcourse tested off just incase of bad labeling)

One night it was working, next morning i had no blue led or power atall..

i have VERY VERY little experience with electronics/soldering

i do have a multimeter, need to grab a 9v for it when radio shack opens tho..

opened the case up, tried to look for bulging caps or heat damage or really anything that may look wrong... absolutely nothing looks wrong..

tho the 2 fuses i can find on the power board (the only board ive really looked at closely so far) are completely opaque white glass tubes so i cant tell if they are blown until i have a way to test (which i would like to request the method to test)

Also, im quite afraid of what ive heard about TV/Monitors storing up a charge, i dont know how to discharge it if it is charged so ive been basically trying not to touch anything but the edges of the boards so far...

802-805 look ok, brown goup on top but they still look good....

donno what else to say, i searched all over for this problem and all i found was post after post of the same problem of power with no image, but ive got no power and couldnt find anything on it, so i apologize if im reposting like the others...

some step by step would be great, i dont have any high quality camera unfortunately either.... but ill see if i can find one from friends/family...

Thank you very much..
..Patrick

[Rtech]

Re: Samsung 245bw No Power No LED

The storing of a charge that may give you a shock, is centred on the large Capacitor on the Power supply, probably reads something like 120uF at 400volts,but this normally discharges in a short time after switching off...although not in every case...use a standard electric light bulb and put across the cap,and that will immediately discharge the cap.
Th first things to do with no Power is check the two fuses on the Board, by putting your Meter on resistance and you should get a very low reading,you can advise them on here and someone will advise,if they seem ok then put the Meter on DC volts and measure the voltage on that large cap,you need power on for this part,but NOT to test the Fuses.Put the Black lead on the negative of the capacitor ,normally indicated by a white line on the side of it,and the red lead on the other pin,and advise.

[Lumberjack777]

Re: Samsung 245bw No Power No LED

tho the 2 fuses i can find on the power board (the only board ive really looked at closely so far) are completely opaque white glass tubes so i cant tell if they are blown until i have a way to test (which i would like to request the method to test)

Normally you would set the multimeter to 200 ohms and touch both sides of the fuses. You'll see it drop to like .01 ohms. That means the fuse basically has no resistance because the fuse is good. It will either not move (bad) or drop down to a very low number (good)

802-805 look ok, brown goup on top but they still look good....

If that 802-805 are electrolytic capacitors. Brown "goup" on top means they have built up pressure and leaked . That's definitely a bad sign. Some clear pictures would definitely be helpful.

Since you admit that you have little experience with electronics or soldering. I would go to youtube and study and learn before attempting a repair. Lots of good videos on replacing capacitors and soldering.

Maybe retiredcaps or somebody else could give you some good youtube soldering and capacitor replacement links if you need some.

It's so much easier if you study and learn before attempting a capacitor replacement. But it's not really that hard when you watch and understand. Good luck.

[retiredcaps]

Re: Samsung 245bw No Power No LED

Maybe retiredcaps or somebody else could give you some good youtube soldering and capacitor replacement links if you need some.

CuriousInventor makes excellent soldering videos

http://www.youtube.com/watch?v=I_NU2ruzyc4

This site has an excellent FAQ with pictures on soldering and cap replacement at

https://www.badcaps.net/forum/showthread.php?t=485

[Ober]

Re: Samsung 245bw No Power No LED

Ok well i tested both white fuses @200ohm , they started ~1.2 and dropped down to like 0.5-0.6

The goop on 802-805 is as other has explained, liek a glue, not so much like damage, theres several others that have dif color glues, this one is just the darkest glue... so just as a test, i tried leavin the multimeter at 200ohm and tested 802-805 and they all came out to ~68 -- so with all 3 responding the same isnt that a good sign?

When doing the power test, do i have to plug EVERYTHING back together (ribbon cables) or just plug the power into the power board?

Also i couldnt find a 400v 120uf cap, but i went ahead and touched the top of all the obvious caps (black tubes) heh, theres only one huge one and it says 450wv 82uF - is that the one that i should worry about possibly havin a charge at times?

Thanks for the help, i greatly appreciate it, once i get responce on ribbon cables for testin the 24v then ill do that and will be ready to the next possibility..

Oh also, ive got the DT-8308 Digital Multimeter, it has 3 locations for the probes... i only had a little experience with the meter before and it was so long ago i dont remember much... i did the fuse test with the probes in the bottom 2 but id welcome any advise on using the multimeter too - which settings and which probes go where when i do the test -- Also keep in mind i had Red in middle hole (labeled V/Ohm/m/A) and Black in bottom (labeled COM) for Fuse Test (was assuming it didnt matter in this case but i know it will in some)

Thanks again..
..Patrick

[Ober]

Re: Samsung 245bw No Power No LED

Just noticed when lookin at it in low light that theres 2 Caps 100uf 10v that have a VERY VERY slight raise in the top, most of them have a crosshatch pushed into the top and are completely flat, these 2 have prob ~1mm raised "cone" top, but it doesnt really look damaged i just wanted to make sure to note it... i believe they are CB879 and CB809 (hard to tell for sure, lots of labels jammed together heh

[Rtech]

Re: Samsung 245bw No Power No LED

Just noticed when lookin at it in low light that theres 2 Caps 100uf 10v that have a VERY VERY slight raise in the top, most of them have a crosshatch pushed into the top and are completely flat, these 2 have prob ~1mm raised "cone" top, but it doesnt really look damaged i just wanted to make sure to note it... i believe they are CB879 and CB809 (hard to tell for sure, lots of labels jammed together heh

You need to change them

[Ober]

Re: Samsung 245bw No Power No LED

is there not a way to test them to be sure? it really looks like it could be from mfg
Thx..

[rogfanther]

Re: Samsung 245bw No Power No LED

Please, post pics of your board(s). Instructions for that are in the signature of retiredcaps post.

[selldoor]

Re: Samsung 245bw No Power No LED

If that 802-805 are electrolytic capacitors. Brown "goup" on top means they have built up pressure and leaked . That's definitely a bad sign. Some clear pictures would definitely be helpful.

802 805 and 807 are 68ohm resistors - they are a classic fail on this monitor

[Lumberjack777]

Re: Samsung 245bw No Power No LED

is there not a way to test them to be sure? it really looks like it could be from mfg
Thx..

If they are anything but perfectly flat on top. They are bad and probably have high ESR. You'd need an ESR meter to test them. "Coneheads" on Saturday Night Live. Good. "Coneheads" on electrolytic capacitors. Bad.

If you have no experience you really need to take your time here. Study those links retiredcaps gave you. You'll understand how to solder and change the caps. You can order those caps from digikey. They usually only cost around 50 cents or so each.

[momaka]

Re: Samsung 245bw No Power No LED

is there not a way to test them to be sure? it really looks like it could be from mfg
Thx..

There is - with a device called an ESR meter. But those cost upwards of $50. New caps online cost much less than that. Better yet, post some pictures so we can see what you are seeing and let you know if there is anything else you should check or anything else you might have missed.

As far as using your multimeter and where to plug its probes, have a look at this video:
http://www.youtube.com/watch?v=bF3OyQ3HwfU

[selldoor]

Re: Samsung 245bw No Power No LED

and touched the top of all the obvious caps (black tubes) heh,[/COLOR] theres only one huge one and it says 450wv 82uF - is that the one that i should worry about possibly havin a charge at times?

I dont know if your having us on or if you are just plain stupid.

I know I'll just go and find a known to be faulty electric item that could be charged to 400 volts and just poke it here and ther.....


Oops!

[Ober]

Re: Samsung 245bw No Power No LED

Selldoor> I meant with the lightbulb! Rofl as was suggested to discharge...

About Pics> i dont have a camera with good enoguh resolution, asked around and noone ive talked ot has anything but phone camera and they are low rez, but im tryin, i definately want to take the pics i just dont have the ability yet...

Debating the ESR meter, it may come in handy later and $50 is cheaper than a new monitor, the more work i have to do on it the more chances to make a mistake..

So is it likely that those 2 caps could be the cause of no power and no led?

Also do i need the ribbon cables plugged in to test the cap that RTech suggested - wasnt sure if you had to have everything plugged together when pluggin in the power cord? is 450wv 82uF the right cap to test? seems scarry to test the thing that can cause harm while plugged in heh - any tips on that test definately appreciated heh..

Thanks..

[Ober]

Re: Samsung 245bw No Power No LED

unfortunately my multimeter was SO different from the one in the video that i really didnt get much from the video... i picked up this meter thinkin it was GOOD cause it had so many options, turns out its "the pain in the ass" meter that you constantly have to change... i dont evne have a clue which selection is "resistance" -- i tried setting it to ohms and puttin on my hand like he did in video, mine doesnt change from the 1 when turned on...

also my red holes show ALL the things he switches between on the same hole while the other is 10ADC (i guess for higher voltage/amperage stuff?) -- makin me wish i hadnt bought this meter, seems like a POS after watchin that video.... i THINK i have another around here somewhere but will have to search..

Edit: Searched, found 3 hard drives i forgot i even owned, but no luck finding the other multimeter...

[selldoor]

Re: Samsung 245bw No Power No LED

Ok - Not that that would do any good!! To make sure the big cap (or any other for that matter) is discharged you need the bulb in a socket with insulated wires - cut the insulation back 5mm and solder to make a probe.
You then touch the "probes" onto the capacitor leads.
Touching the tops will do nothing.
If there are heat sinks take care not to touch them as they can hold a charge as well.

ESR meter yes cheaper than a new monitor but a lot more than a new set of caps and you may still have to buy most of the caps anyway.

You do really need to plug everything in to test the voltage on the connectors.

The BIG 450v cap is the one to test first.

Do couple of dummy runs without the power on so you get used to looking at the meter and the probes.

Meter on VDC 600 put the black probe on the negative leg of the cap and the red probe on the positive leg.
Some probes have little aligator clips use them if you have them but make sure they cant slip.

You need to do the test twice once when it is just plugged in and again after you press the power button.


I will post some ideas for your meter

[selldoor]

Re: Samsung 245bw No Power No LED

Ok - They come in Black and yellow - is yours like the attached pic.
I have put some red labels on and where to plug in the probes.
If it is not like this tell me.
Have you given us the part number off the power board just so we know
we are talking about the same ( or at least very similar)

[Ober]

Re: Samsung 245bw No Power No LED

Alrighty, i wonder why it was suggested to just touch the lightbulb to the cap, glad ive still been very careful not to touch anything, i woulda been under the assumption it was completely safe at that point.... grr... Is there an easier way to discharge? i dont think i even have a lamp and it would be kinda tough to get everything high up to my ceiling bulbs...


Part Info for Power Board
Made in Korea
Model: HUB-24P 4-26-2007
Written on both sides: BN44-00173A


Yes, thats exactly the multimeter ive got...

[momaka]

Re: Samsung 245bw No Power No LED

unfortunately my multimeter was SO different from the one in the video that i really didnt get much from the video... i picked up this meter thinkin it was GOOD cause it had so many options, turns out its "the pain in the ass" meter that you constantly have to change... i dont evne have a clue which selection is "resistance" -- i tried setting it to ohms and puttin on my hand like he did in video, mine doesnt change from the 1 when turned on...

The only reason I posted that video was to show you the techniques the guy was using for measuring voltage and resistance. The only difference between your multimeter and the one in the video is that yours is manual ranging so you have to sort of know which range to select before making a measurement. That's actually not very hard. In some cases, it's even better.

Knowing number prefixes and what they mean is key here.
- kilo (or k) is 1000 times the base number
- mega (or M - note that it's a capital M) is 1000000 (1 million) times the base number
- mili (or m) is 0.001 (1/1000) times the base number
- micro (or u) is 0.000001 (1/1000000 or one millionth) times the base number

Also, a "1" on the left side of your multimeter indicates an out-of-range reading. If you are trying to measure DC voltage on a battery, for example, and you get a "1" on the left side of the screen, then select the next higher scale on the DC range on your multimeter. This technique is applicable to the other ranges as well.

also my red holes show ALL the things he switches between on the same hole while the other is 10ADC (i guess for higher voltage/amperage stuff?) -- makin me wish i hadnt bought this meter, seems like a POS after watchin that video.... i THINK i have another around here somewhere but will have to search..

There's nothing wrong with your multimeter. I have one almost like yours and I've been using it for 10 years now. I think you just need to spend some more time online reading how to use multimeters.

And to prevent you from doing damage to your multimeter, monitor, and injury to yourself, just connect the leads as shown in selldor's picture (i.e. black lead to COM, and red lead to Volts/Ohms/mA).

[selldoor]

Re: Samsung 245bw No Power No LED

Its getting late over here - it usually is fairly safe - what I suggest is after the board has been off for a while do the test and see if you get anything on the big cap it may hold a residual 5v but be careful just in case the built in discharger in the cap is not working.
Have a couple of trys with the voltage off then do it for real.
Hopefully you will only have to do the high voltage test twice then everything else will be low