# Can someone identify this part?

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#### XenonKilla

##### New Member
I just had my Samsung monitor go out on me. I came home the other night and hit the space bar on my computer to turn my monitors on and only one of them came on. I have two of the same monitors Samsung SyncMaster's 953BW setup via multi-desktop. Well like I said I came home and only one of them came on. When I say came on I mean that an image appeared on the screen. Both monitors were on they were just in sleep mode as I could still see the flashing blue power light on both monitors.

I took both monitors apart and just started swapping parts between the two so that I could narrow down where the issue is coming from. I narrowed the problem down to this board below...

Also compared the the good board, the bad board makes like a high pitched whine coming from somewhere around that yellow thing you see below...

So I'm wondering what the heck that yellow thing is called so that I could perhaps replace it with a new one. Also anyone who knows their stuff about these kinda things do you think that it could be that yellow thing or possibly something else? Like I said the monitor turns on it just won't display an image on the screen. But when I swapped this board out with my good monitor then the monitor works fine again.

#### markwhi

##### New Member
That's a transformer. You'd need to know the specs on the transformer to replace it, though you might be able to order a replacement board from Samsung.

#### markwhi

##### New Member
Also, that looks like the power supply board. It'll take the mains voltage and turn it into whatever the monitor wants. So you could call Samsung and give them the model of the monitor and ask to buy a replacement power supply board.

#### Torben

##### Well-Known Member
Hi there,

I'll start with my usual disclaimer that I'm strictly a hobbyist and that there are others on the board far more qualified to help you out. But I'll stick my neck out and hope that a) it might give you something to go on, and b) if I screw up I'll be corrected.

That looks like the power supply board and the yellow thing looks to me like an HF transformer. Could be humming because it's shot, or something else on the board could be shot and causing the transformer to hum.

I understand that many transformers of this kind are specially designed for their circuits, so there's a chance that you could only get one from Samsung--and they might not be selling. You'd have to contact them to find out. I tried a few quick searches for replacement parts for Samsung monitors and came up empty, but someone else might have a link or two for you.

I'd guess that if you were to take the thing in for repair, they'd not even bother replacing the transformer but just pop in a new power supply board.

If you haven't already tried, you might want to search around on Tech Support, Manuals & Troubleshooting for Consumers for information, and if you don't find anything, you can post your question there as well (although the answers here will probably be more in-depth).

Sorry I couldn't be more help. Like I said, though, somebody with more information may happen along before too long.

Good luck!

Torben

#### XenonKilla

##### New Member
Wow you guys are SUPER HELPFUL! Thanks!

Yes it's definitely the power supply board, I guess I should have pointed that out earlier haha. Like I said I am not 100% sure that the problem is the transformer itself, just as Torben said it could be something else causing the transformer to act up. There is a local electronics store that is pretty big on these kinda things (no I'm not talking about Radio Shack lol) and I am thinking of taking the power supply board in there and seeing if they might know what to look for etc. I just hate to throw this monitor away when I know that the only thing wrong is just something on this darn board.

#### markwhi

##### New Member
I'd suggest checking with Samsung to see what a replacement power supply board would cost. It might not be that much, and it might be worth it in time savings just to do that

#### unclejed613

##### Well-Known Member
i hope your warranty was expired, 'cause you just voided it if it wasn't..... samsung has a lot of high speed rectifiers that go bad, as well as capacitors that go bad. if you don't know how to properly pick a replacement diode (that's the black things with the stripe on one end) or check the caps (the beer can shaped things next to the diodes) i don't recommend you try it. transformers do occasionally go bad, but are not as likely as the caps or diodes. judging by the discoloration of the circuit board around the two diodes standing up, and the fact that the marker ink dots on the tops of the caps is bubbled up, i would suspect diodes and caps first. you might want to take this one to someone with some experience with switching supplies. if the transformer is whining and not chirping, then the overcurrent circuit isn't shutting down the switcher, and that could be yet another problem.

too bad.... the date code on the transformer is March 2008. if you had more than a 1 year warranty, or you bought it less than a year ago, you lost out. if it was a 1 year warranty and you bought it more than a year ago, it would be a COD repair anyway.

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#### ronsimpson

##### Well-Known Member
You cannot get a new transformer. If you have two boards you could swap parts. First use a meter to compare the resistance (or diode test readings) of all diodes. These Samsung boards had some bad solder problems. Check all solder joints. I do not have drawings, I left this group of Samsung about the time this monitor came out.

#### XenonKilla

##### New Member
i hope your warranty was expired, 'cause you just voided it if it wasn't..... samsung has a lot of high speed rectifiers that go bad, as well as capacitors that go bad. if you don't know how to properly pick a replacement diode (that's the black things with the stripe on one end) or check the caps (the beer can shaped things next to the diodes) i don't recommend you try it. transformers do occasionally go bad, but are not as likely as the caps or diodes. judging by the discoloration of the circuit board around the two diodes standing up, and the fact that the marker ink dots on the tops of the caps is bubbled up, i would suspect diodes and caps first. you might want to take this one to someone with some experience with switching supplies. if the transformer is whining and not chirping, then the overcurrent circuit isn't shutting down the switcher, and that could be yet another problem.

too bad.... the date code on the transformer is March 2008. if you had more than a 1 year warranty, or you bought it less than a year ago, you lost out. if it was a 1 year warranty and you bought it more than a year ago, it would be a COD repair anyway.
Warranty haha dude even if there was a warranty I seriously wouldn't waste my time waiting around for Samsung to fix my monitor. I have already bought a replacement but as stated before I just don't wanna throw this one away when there's a possibility that it can be easily fixed.

Yes I know what capacitors and diodes are I will try to test those out and see if perhaps one of them has gone bad.

One thing I will mention is that before when I mentioned that I could hear a high pitched noise, well when I listen closely I can hear the whine kind of pulsing. Not sure if that adds any insight to anything

#### unclejed613

##### Well-Known Member
if the whine is pulsing, that's what i meant by chirping. so yes something is shorted, most likely those diodes and the caps are probably bad too. those are high speed rectifiers, and not just any diode will do. i used to know where to find 1000V 50ns 3A diodes at one time, probably Mouser or Digi-Key. i'm looking into getting SiC (silicon carbide) diodes to take care of samsung power supplies that continuously pop diodes. SiC diodes have ZERO recovery time, and so run much cooler than silicon FR or schottky diodes, and are available in 600V and 1200V PIV ratings.

sorry, you didn't know what the transformer was, so i guessed (wrongly) that you might be fuzzy on the diodes and caps too....

#### XenonKilla

##### New Member
Oh it's cool man no worries, I just didn't wanna look like a total noob lol.

Well what threw me off is that I took everything in to an electronics place today and the guy repairs TV's, Satellite boxes, LCD Monitors etc. Well I showed him everything and I told him everything I have told you guys and I was asking him how long and how much to fix it and he said around $70 bucks and he could have it done in a day or two. I also asked him if he thought it was the yellow thing and he referred to it as the "pot" which I think he only said that because it says HI-POT on it. His exact words were "yes if it's the pot then that will only cost around$20 bucks to replace plus labor etc". But it was almost like he knew that the problem was something else but just didn't wanna say so that perhaps he could charge me more money. I dunno it just sounded fishey to me and there is just way to much shady **** going on out there these days and I know how people like to take advantage of other people who might not know exactly what they are looking at.

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#### unclejed613

##### Well-Known Member
part of the problem is that there's so much going on inside a piece of equipment these days, that you can't know for sure whether something else went wrong at the same time, like the panel going bad, or the main board, until you get the power supply running again.

##### New Member
At least one of those caps looks bulged to me. When I was fixing my Dell monitor, a high-pitched whining/pulsing sound could be heard from inside the case. Sure enough it was the caps...

#### karyoker

##### New Member
High pitched whine is a short in the output side. Prob a filter.

#### sheldonstv

##### New Member
firs thing you need to do is visually check all yr electrolytics-any with bulging tops or split cases need replacing(use 105 degree hi temp,and same value cap at same working voltage or above).... if the smps is pulsing the fault is either related to the primary side of the supply or the secondary side
check all diodes on yr secondary for s/c,on the primary side check all high value resistors for oc or changed value-i see there is a chopper ic fitted -just above that there is a single electrolytic on its own check that for hi esr,also check all diodes on the primary side for s/c
the chopper transformer wont be at fault before making any measurements make sure the big smoothing cap by the bridge rectifier has been discharged-also dont connect any test equipment(scope etc)without using an isolation transformer.........

#### mbarazeen

##### Member
i suspect its a capacitor that got damaged, as some one told above, check visually you can find it out, i have experience in changing capacitors in many cases of switch mode power supplies.

razeen

#### unclejed613

##### Well-Known Member
i've had a little time to do a more detailed study of the picture, and here's what i see. i have circled in red some things to take a closer look at. on the far left, the green resistor-like device is a fuse, you'll want to check that and make sure it's not open. i think that feeds the inverter for the backlight, which is the large balck transformer. under the arrow marked SOLDER is where the driver IC for the inverter is. that section of the board is dark from heat. next i have marked a capacitor and a blue ink mark on the board next to it. looking at the top of the cap, it looks like the ink mark fades from blue to black, possibly an indication of a thermally sensitive ink. all of the caps look as if they have got hot enough to burn the ink, and that's why the ink looks bubbled up on them. also the diodes i've circled have obvious signs of producing enough heat to discolor the board under them. over to the right, next to a cap is a device that looks like it's marked IC102. it's probably a "transistor fuse" and it looks like it's glued to a cap. if it is a fuse, it should have two pins and read as a short. i would replace all of these secondary side caps and check all of the diodes.

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#### XenonKilla

##### New Member
i've had a little time to do a more detailed study of the picture, and here's what i see. i have circled in red some things to take a closer look at. on the far left, the green resistor-like device is a fuse, you'll want to check that and make sure it's not open. i think that feeds the inverter for the backlight, which is the large balck transformer. under the arrow marked SOLDER is where the driver IC for the inverter is. that section of the board is dark from heat. next i have marked a capacitor and a blue ink mark on the board next to it. looking at the top of the cap, it looks like the ink mark fades from blue to black, possibly an indication of a thermally sensitive ink. all of the caps look as if they have got hot enough to burn the ink, and that's why the ink looks bubbled up on them. also the diodes i've circled have obvious signs of producing enough heat to discolor the board under them. over to the right, next to a cap is a device that looks like it's marked IC102. it's probably a "transistor fuse" and it looks like it's glued to a cap. if it is a fuse, it should have two pins and read as a short. i would replace all of these secondary side caps and check all of the diodes.
WOW Thanks a lot man! I will definitely give all that stuff a try and let you know how it turns out

#### Nigel Goodwin

##### Super Moderator
As many others have suggested, the most likely cause is one of the rectifiers S/C - this causes the TX to whistle.

#### XenonKilla

##### New Member
Well I took the board to a local electronics shop a couple days ago. Picked it up today and asked what was wrong. The guy told me a couple of caps, a diode, and an IC Chip. I was charged \$77 bucks for the repair. The repairs sounded kinda suspect so I got home and tore it back apart to see what was replaced. As I suspected the guy is a lying piece of ****! The only thing that I can see that was replaced were the two CAPS pictured below.

I checked on the bottom of the board and I can CLEARLY see soldering marks on the bottom of the board where these two caps were replaced. What I can't find are ANY OTHER MARKS ANYWHERE on the bottom of the board. Plus compared to my pictures that I took BEFORE I dropped the monitor off for repair all the other chips match except for the two CAPS that were replaced.

Needless to say I am heading back down there right now to confront the guy about this. It's people like this that remind me why I try to handled EVERYTHING MYSELF and not rely on the worthless pieces of **** that are out there in the world today!

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