Samsung Syncmaster 225BW

[Hunt]

Is this cap problem getting worse or better?

Can admin delete this as it could be called thread hijacking. Sorry.

[jetadm123]

Re: Samsung Syncmaster 225BW

I received my replacement power board from china (e-bay purchase referenced above) and it doesn't seem to power the backlights at all. I haven't had time to play with it, just plugged it in quickly to see if it would work but alas no luck.

Are there any known issues/differences between Rev 1 and Rev 2 boards? I'm replacing a Rev 1 with a 2.

More info: this particular monitor had the caps replaced 2 years ago. Lately it started flickering. To isolate the problem, I swapped a known working powerboard out of another of my 225BW's and it corrected the problem. This tells me it was a problem on the board.

I plopped a replacement board in, hit power and I get nothing on the screen, it doesn't even fire up for a second displaying the Analog/Digital box in the top left. I haven't had time to look close enough to see if there is a picture on the LCD using a flashlight, more later on that.

The power button lights blue, no image comes, the power button then goes to blinking blue.

I'll investigate further but off the top of your head (Bill or others) do you know of any material differences between the revisions of the boards and if they are compatible with each other?

Thanks



With the board installed,

Maybe you can post photos of the rev1 and rev2 boards and perhaps a sharp eyed member can spot the difference.

[jetadm123]

Re: Samsung Syncmaster 225BW

do u know what size of ccfls do i need? or where can i get CCFL LAMPS FULL ASSEMBLIES for Samsung Syncmaster 225BW?

Try ccflwarehouse.com. Email them if you can't find what you're looking for. They're very helpful.

[termit]

Re: Samsung Syncmaster 225BW

do u know what size of ccfls do i need? or where can i get CCFL LAMPS FULL ASSEMBLIES for Samsung Syncmaster 225BW?

[Konesky]

Re: Samsung Syncmaster 225BW

I received my replacement power board from china (e-bay purchase referenced above) and it doesn't seem to power the backlights at all. I haven't had time to play with it, just plugged it in quickly to see if it would work but alas no luck.

Are there any known issues/differences between Rev 1 and Rev 2 boards? I'm replacing a Rev 1 with a 2.

More info: this particular monitor had the caps replaced 2 years ago. Lately it started flickering. To isolate the problem, I swapped a known working powerboard out of another of my 225BW's and it corrected the problem. This tells me it was a problem on the board.

I plopped a replacement board in, hit power and I get nothing on the screen, it doesn't even fire up for a second displaying the Analog/Digital box in the top left. I haven't had time to look close enough to see if there is a picture on the LCD using a flashlight, more later on that.

The power button lights blue, no image comes, the power button then goes to blinking blue.

I'll investigate further but off the top of your head (Bill or others) do you know of any material differences between the revisions of the boards and if they are compatible with each other?

Thanks



With the board installed,

[nmjwolf]

Re: Samsung Syncmaster 225BW

Sorry, my wording is a bit confusing.

From reading the datasheet, if OVP were "tripped", it would be around 2V DC. Since it is 0V, my interpretation is that OVP is not "tripped".

my interpretation as well. CCFL's it is.

I appreciate your help.

[retiredcaps]

Re: Samsung Syncmaster 225BW

Datasheet shows OVP going into the fault protection logic...so I assume if this is 0V then that part of the circuit is not enabled...ie chip is not faulted.

Sorry, my wording is a bit confusing.

From reading the datasheet, if OVP were "tripped", it would be around 2V DC. Since it is 0V, my interpretation is that OVP is not "tripped".

[Konesky]

Re: Samsung Syncmaster 225BW

I was planning on buying this power board from eBay as it is the cheapest new one available, however the layout is slightly different and it is marked 225BW Rev 0.2. Will this be compatible with what I have? http://www.ebay.com/itm/New-Samsung-...#ht_3166wt_986

Thanks again.

It looks similar but there is just no way for me to tell. I suspect the different revisions are compatible but I cannot confirm that so perhaps for the sake of a couple bucks, you may want to match it with your current revision. Good luck!

[nmjwolf]

Re: Samsung Syncmaster 225BW

Datasheet shows OVP going into the fault protection logic...so I assume if this is 0V then that part of the circuit is not enabled...ie chip is not faulted.

Thanks for your help.

[retiredcaps]

Re: Samsung Syncmaster 225BW

The measurements are:
pin 2 0V DC

Pin2 (OVP) is not enabled. It would be at 2V if it were.

Pin14 2.35V DC
pin 15 0V DC

For pins 14 and 15, I don't know if that is correct for the brightness or not.

Anyway, other than pin 14 and 15, I think most of the electronic components on the inverter board are functioning. That leaves you to check the ccfls.

[nmjwolf]

Re: Samsung Syncmaster 225BW

The measurements are:
pin 2 0V DC
Pin14 2.35V DC
pin 15 0V DC

[retiredcaps]

Re: Samsung Syncmaster 225BW

I suppose at this point I should stop being so cheap and buy a set of CCFL's

Well, I personally would like to see the voltages on pins 2, 14, and 15 before you spend any money. If pin 2 comes back with OVP enabled, then you know it is the ccfl OR the wiring is burnt away and not making contact with the ccfl bulb. This is the farthest I have helped someone in this pwm area. I feel like a starting pitcher in the 8th inning and trying to complete the entire game!

The pwm IC works as "all or nothing" (in lay terms). Either all the bulbs work or none at all.

Sometimes you can find a working monitor (like my example in the above post) for cheaper than a new set of ccfls.

[nmjwolf]

Re: Samsung Syncmaster 225BW

I suppose at this point I should stop being so cheap and buy a set of CCFL's

[retiredcaps]

Re: Samsung Syncmaster 225BW

4.96vdc chip is enabled

That looks good. What about the DC voltages on pins 14 and 15? Also pin 2 (OVP)?

PS. My local ad shows a working 225 BW on sale for $15 (a good price IMHO). If I didn't have working lcds and a few waiting for repair, I would probably buy this.

PPS. Well, I knew it wouldn't last, the 225 BW has been sold.

[nmjwolf]

Re: Samsung Syncmaster 225BW

4.96vdc chip is enabled

[retiredcaps]

Re: Samsung Syncmaster 225BW

i measure 4.96VDC to gnd.

Okay, the pwm is getting power. Now check pin 3 (ENA). According to the datasheet, the IC is enabled when voltage on pin 3 is > 2V.

Also, pin 15 and 14 have something to do with dimming the ccfls. I'm not sure though what is 100% and what is 0%.

[nmjwolf]

Re: Samsung Syncmaster 225BW

OZ964 is the pwm chip. Datasheet is at

http://pdf1.alldatasheet.com/datashe...TC2/OZ964.html

Refer to datasheet for pin numbering.

Pin 5, VDDA, is the supply voltage. Pin 6 is ground. (Page 2).

Measure the DC voltage on pin 5 using pin 6 as ground. The recommended operating range for VDDA is between 4.6V and 5.5V.

i measure 4.96VDC to gnd.

[chez71]

Re: Samsung Syncmaster 225BW

Hey Chez,

Sorry it took so long to get back to you. Some of your caps look bad to me from the pictures but it's hard to tell. In the last picture, the ones in the bottom left look bad.

What you're looking for is for the end of the capacitor to be bulging out a little or even for a brownish (in this case) fluid to be leaking out. It should be noted that even if a capacitor does not exhibit external signs of failure, that doesn't mean it hasn't.

It's cheaper to order parts from digikey and install them yourself however if you don't have a soldiering iron laying around and you're not completely comfortable replacing them, it may make more sense to order the replacement board off of E-bay and save yourself the trouble.

Here are some examples to help guide you:


http://www.instructables.com/id/Fix-...Bad-Capacitor/



http://www.stevenjohal.com/lcd-scree...wer-no-signal/


These caps are good:


Hope that helps, GL!

-Konesky

Thank you very much for the info! I think I'm gonna be lazy and just buy a complete new power board because I'm way to busy to learn how to replace caps right now.

I was planning on buying this power board from eBay as it is the cheapest new one available, however the layout is slightly different and it is marked 225BW Rev 0.2. Will this be compatible with what I have? http://www.ebay.com/itm/New-Samsung-...#ht_3166wt_986

Thanks again.

[retiredcaps]

Re: Samsung Syncmaster 225BW

OZ964CN

OZ964 is the pwm chip. Datasheet is at

http://pdf1.alldatasheet.com/datashe...TC2/OZ964.html

Refer to datasheet for pin numbering.

Pin 5, VDDA, is the supply voltage. Pin 6 is ground. (Page 2).

Measure the DC voltage on pin 5 using pin 6 as ground. The recommended operating range for VDDA is between 4.6V and 5.5V.

[nmjwolf]

Re: Samsung Syncmaster 225BW

Got some better light here are the details:

OZ964CN
T01053 2P
0633C