Samsung Syncmaster 2233RZ possible bad caps. Need help

[Gouda]

Hey all. Wonderful forum here. Been parusing past few days learning what I can. I have a Samsung Syncmaster 2233RZ 22 inch 120hz monitor that the screen will stay on for 2 seconds and then go black but the LED light is still lit. I have a feeling it's bad caps so I am diving into replacing them. This is a first for me but I watched a few youtube videos and doesn't seem that difficult.

The question I have is regarding what caps to get. I am trying to get them from digikey and looking for low ESR caps which is where I'm getting a bit confused.

I am going to need

4x 820uF 25V 105c's
3x 100uF 10V 105c's.
1x 3.3uF 50V
1x 47uF 50V
1x 330uF 10V

Which one's should I get to recap this board? None of them looked like they are bulging but I've had this monitor for 5 years and it was a hand me down and friend had it a cpl. Hoping to bring it back to life.

[JonathanAnon]

Re: Samsung Syncmaster 2233RZ possible bad caps. Need help

It could be the capacitors, but it could also be one of the elements of the inverter system. Before you go off and buy a load of capacitors, I would probably test for shorts on the high voltage transformers and MOSFETs on the inverter section...

When the screen comes on and then shuts down immediately it can be indicative of a problem on the inverter section... i.e. problem with the CCFL bulbs, shorted transformer etc etc... Tell me, when the screen shuts down
i) Can you still hear the audio?
ii) Can you see the outline of the video on screen when you shine a torch on it?

[Gouda]

Re: Samsung Syncmaster 2233RZ possible bad caps. Need help

Thanks for the reply. I'm not sure. I have it completely apart right now. I can try putting back together and test that out. While I have it apart though, should I look deeper? Not sure what the MOSFETS are and I don't own a multimeter. Had one back in the USAF but they wouldn't let me take it with me.

P.S. The type of capacitors are Sam Young and the reason I suspected those is due to all the threads I have found of people having bad caps with the Samsung syncmasters.

[JonathanAnon]

Re: Samsung Syncmaster 2233RZ possible bad caps. Need help

The capacitors sometimes show visible signs of failure. Usually people take a few high quality images of the relevant boards, back and front, and post them on the thread. Why not do that, then put the screen back together and have a look at it with a torch and see if the video is still there.

It may be the case that replacing all the caps will work. If it was mine though, I would test a little further for two reasons ...
i) the caps may all be fine, and you could spend a lot of time and money replacing them without getting a fix... I've done that and it's really annoying :-(
ii) Usually it will be just one group of capacitors that has failed, and the others are still fine... disclaimer: a lot of lads on here just recommend replacing all power supply capacitors anyway...

[Gouda]

Re: Samsung Syncmaster 2233RZ possible bad caps. Need help

Not sure if these attached or not. Hopefully they did.

Edit: Looks like they did attach. Here is front and back of the power board. As I stated before I don't see any blown or bulging caps but doesn't necessarily mean they aren't dried up. This is a 5+ year old monitor.

[theOracle]

Re: Samsung Syncmaster 2233RZ possible bad caps. Need help

none of the caps in your photo appear to be bulging

as far as which ones to get, well Digi-Key has this cool filter selector tool, and you keep adding filter conditions such as brands, voltages, temperatures etc. and pretty soon you have a cery short list of candidates

So let's do the first one together!
4x 820uF 25V 105c's

I would start with the following filters:

check the check box labeled - In Stock

Manufacturer - use you control key and select these 4 ---> Nichicon, Panasonic, Rubycon, United Chemi-con
Packaging - Bulk
Capacitance - the original value i.e. 820uF
Voltage Rating - the original value and also the next several above it, so in this case perhaps 25V up through 50V
Operating Temperature - select every entry that is 105
Size/Dimension - measure the width (diameter) of yours and select that plus a couple smaller
Mounting Type - Through Hole

Leave the other filters alone and then hit the Apply Filters button

now you will be presented just a very few choices rather than 1000's and you can sort the results based on ripple current or ESR or impedance or price or whatever

[PeteS in CA]

Re: Samsung Syncmaster 2233RZ possible bad caps. Need help

Not sure what the MOSFETS are and I don't own a multimeter.

A decent handheld DMM isn't a bad thing to have around the house.The Fry's store in Campbell (Highway 17 and Hamilton Ave.) has a decent selection of DMMs, and I assume the stores in San Jose, Sunnyvale and Fremont (whichever is nearest to you) do as well. Fry's carries Fluke, which I would regard as in the first-tier in general purpoose test equipment (along with Tektronix and Agilent), and Extech, which I consider second-tier but very good quality (and often at a better price than Fluke). Fry's is better than Best Buy if you want to get into BYO computers, upgrading/repairing computers, and general purpose electronic components.

I don't know where you are in terms of your career and stage of life, but some basic courses in electronics at a local JC (San Jose City College, Evergreen, West Valley, Mission and De Anza come to mind) might be a good start (and not too expensive).

[JonathanAnon]

Re: Samsung Syncmaster 2233RZ possible bad caps. Need help

Before you remove any of the capacitors, I would number the caps and their corresponding position on the circuit board. If I'm replacing a load of capacitors I usually take a picture of the board and photoshop in the value and voltage of the capacitor at each position. Or I get those plastic numbered stickers and put one on each cap and a corresponding one for the spot on the board. You dont want to be in the position where you desolder all the capacitors from the board and then cant remember which ones went in which positions..

Almost all boards have the polarity marked on them so you dont need to worry about recording this.. But you do need to make sure that the new capacitors are put in the right way round...

With regard to solving the shutdown problem, I had a similar Samsung where the inverter transformer failed. I would check this for shorts before proceeding further, but you will need a digital multimeter for this. Even a cheap one should be able to give you enough information to decide whether it's shorted or not.

[Gouda]

Re: Samsung Syncmaster 2233RZ possible bad caps. Need help

Thanks for the reply guys. I had some basic electronics experience in the air force. I used a Fluke MM pretty much every day toning out pairs and pinouts for cables I was making.

A fellow San Joser! Whats up!? I was at Fry's off of Brokaw the other day looking at Capacitors there but all they sell and all Radioshack sells are a brand called NTE. After bunch of reading it sounded like Rubycon or Panasonic is where I want to be at when it comes to caps.

Could you maybe expand more on the inverter section and what I might need to do to see if that's bad?

[theOracle]

Re: Samsung Syncmaster 2233RZ possible bad caps. Need help

I was at Fry's off of Brokaw the other day looking at Capacitors there but all they sell and all Radioshack sells are a brand called NTE. After bunch of reading it sounded like Rubycon or Panasonic is where I want to be at when it comes to caps.

Really Nichicon and Chemi-con are every bit as good of caps as Rubycon or Panasonic - all 4 of those manufacturers has had a dud series, but they make BILLIONS of caps every year that are fabulous and reliable.

It's like just because someone you know who had a Honda, once had a problem with his Honda and had to get it repaired, that doesn't make Honda's unreliable.

Nichicon had a bad series called PF and later HM/HN
Chemicon had bad series called KZG/KZJ
Rubycon had a bad series called MBZ/MCZ

These companies had had hundreds of cap series and produced trillions of caps, rarely EVER do they put out any caps with issues.

These 4 are still ALL great quality companies making great caps and I use all 4 interchangeably, but I would not care to trust most any other company's caps.

PS - sometime you can find some Nichicon's at Radio Shack