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Old 03-06-2013, 06:21 PM   #1
tibimakai
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Default Samsung Syncmaster S23A550H no video on VGA

I have got this monitor from my work place, since it would not work with a VGA signal.
They didn't test it out with other inputs, but I have tried it out with an HDMI signal and the monitor works.
It tries to switch to analog, but then the picture becomes black, even the backlight turns off.
It seems that the analog signal doesn't work, but the digital it works.
What could it be the problem with it.
It has the latest firmware, at least the software that what is states when I try to install it.
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Old 03-06-2013, 06:54 PM   #2
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Default Re: Samsung Syncmaster S23A550H no video on VGA

I would check the protection diodes for each signal pins around the VGA connector.
See PDF for example.
Attached Files
File Type: pdf DVI_VGA protection diodes.pdf (203.9 KB, 136 views)
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Last edited by budm; 03-06-2013 at 06:59 PM..
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Old 03-06-2013, 10:01 PM   #3
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Default Re: Samsung Syncmaster S23A550H no video on VGA

There are three double diodes and two double zenners behind the D-Sub connector.The diodes are MFW15 and the zenners are KZ4 Y6.
On the diodes I measure on one pin 4.99Z and )V on the other two pins.
On the zenners on both double pins are )V and on the single pin side on one zenner is 0V and on the other I measure between 0.34-0.7V.
Not sure what should I check.
Those three double diodes, if I check with the diode checker one side shows on all three 0.5V and the other side 0.075V and beeps.
The zenners shows exactly the same as on the HDMI side. The diodes are not showing the same readings.
In the next hour I will post some pictures.
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Old 03-06-2013, 10:17 PM   #4
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Default Re: Samsung Syncmaster S23A550H no video on VGA

You can use Ohm mode to look for shorted out Diode since we are looking for low resistance, when semiconductor shorted out it will be just like low value resistor (low ohm reading both ways).
As you can see in the sample in the PDF, the Diodes have one leg connected to ground (see if your monitor uses the same setup), so you can use Ohm meter between the Ground and check each as shown in the Diagram to see if one of those signal pin is shorted to ground.
Per diagram, the protections Diodes are on pin 1, 2, 3, 5, 9, 12, and 15.

Last edited by budm; 03-06-2013 at 10:26 PM..
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Old 03-06-2013, 10:41 PM   #5
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Default Re: Samsung Syncmaster S23A550H no video on VGA

It looks very similar.
There are three double diodes(like a SMD transistor) and two double zenner diodes(same as the other three).
The zenners look good, but the three diodes between two legs show 75.5 Ohm on all three diodes.
All three could be bad? Or should I remove them and check again.
On the HDMI side they show as I would expect to show a good diode.
Camera battery is charging now.

Last edited by tibimakai; 03-06-2013 at 10:43 PM..
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Old 03-06-2013, 10:44 PM   #6
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Default Re: Samsung Syncmaster S23A550H no video on VGA

The monitor will still work without the Diodes, so you can remove the suspect diode one at at time to see if it VGA will work. The 75 Ohm may be the termination resistors for the Red, Green, and Blue signal lines (pin 1, 2, 3) that you can see in the diagram.

Last edited by budm; 03-06-2013 at 10:48 PM..
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Old 03-06-2013, 11:12 PM   #7
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Default Re: Samsung Syncmaster S23A550H no video on VGA

Removed the diodes and tested them and they are all good.
The monitor still doesn't run without them. Must be something else.
Why would the backlight turn off when the VGA is plugged in?
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Old 03-06-2013, 11:13 PM   #8
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Default Re: Samsung Syncmaster S23A550H no video on VGA

If the monitor does not detect signal from PC, it will go into standby mode, that is why I have you check and see if the signal lines are shorted to ground or not. i believe right now the video processing circuit is not seeing the VGA signal from the VGA port.
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Old 03-06-2013, 11:20 PM   #9
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Default Re: Samsung Syncmaster S23A550H no video on VGA

I will check, but if nothing is plugged in it sits on the HDMI screen with backlight on.
If I plug in the VGA it tries to switch it, shows up the VGA logo like twice and then go black and the backlight turns off.
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Old 03-06-2013, 11:24 PM   #10
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Default Re: Samsung Syncmaster S23A550H no video on VGA

The middle pin is the 75.3 Ohm, one of the two pins is 0.3 Ohm(GND) and the third one is 2.5 Kohm. Without VGA plugged in.
Should I check with the VGA plugged in, or without it.
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Old 03-06-2013, 11:29 PM   #11
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Default Re: Samsung Syncmaster S23A550H no video on VGA

With the cable plugged in, but no signal(PC off) the resistance at the middle pin drops to 38 Ohm.
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Old 03-07-2013, 12:04 AM   #12
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Default Re: Samsung Syncmaster S23A550H no video on VGA

Found a board for $39.95 shipped and I have purchased it.
Thank you for your help.
It's amazing, these LED monitors how small board have in them. It's like 6" x 5". It's a single board.
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Old 05-08-2013, 10:19 AM   #13
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Default Re: Samsung Syncmaster S23A550H no video on VGA

Hi,

I have the same monitor and the same issue. Where did you buy the replacment logic board?
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Old 05-09-2013, 03:16 AM   #14
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Default Re: Samsung Syncmaster S23A550H no video on VGA

Quote:
Originally Posted by tibimakai View Post
I will check, but if nothing is plugged in it sits on the HDMI screen with backlight on.
If I plug in the VGA it tries to switch it, shows up the VGA logo like twice and then go black and the backlight turns off.
FYI speaking from own investigations and personal experience: the 2xSA550 series (21", 23" and 27") is plagued by corrupted firmware. Reflashing the firmware usually resolves this.
The issues described in this thread appear to have another cause, though. But I guess it can't hurt to reflash the firmware just to exclude this as a possible cause.

I bought a defective 27" one about 3 weeks ago, incredibly it was only 1,5 years old. The seller said he couldn't claim warranty as he didn't have the receipt anymore.

When switched on, the monitor did not display anything besides a box 'Check Cable'. No dice either through HDMI or VGA, but when connected to my laptop monitor brand and type were identified correctly. It just did not give any picture.

Samsung is aware of the firmware issues and has a firmware update for these models avaliable on their website ('SA Series LED Monitor Quality Improvement Announcement'). Download, install, and reflash the firmware. Through the VGA cable, pretty neat
At the end of reflashing the monitor switches itself off. Turn it back on, and voila, we have an image. My 27" has worked flawlessly ever since, both on my laptop (VGA) and mediaplayer (HDMI). Very nice picture as well

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Old 05-09-2013, 10:05 AM   #15
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Default Re: Samsung Syncmaster S23A550H no video on VGA

I'm about to pick one up today(27") with the same issue a you.
Thanks for the hint.
They have the board if you need it, but it's more expensive now.
http://www.ecrater.com/p/13979316/sa...48p-main-board
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Old 05-10-2013, 08:00 PM   #16
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Default Re: Samsung Syncmaster S23A550H no video on VGA

Wow, you are awesome!
The S27A350H had the same issue, with the Check bable on the screen, and by doing the firmware upgrade through VGA cable, it works great now.
I had to install a driver first. I couldn't find the software on the US site, I found it on the Canadian site.
Thank you for this.
Maybe the other 23" monitor, had the same issue and I have changed the mainborad. But I still had a $60 profit on it, ince it was a free monitor
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Old 05-11-2013, 06:20 AM   #17
re-atari
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Default Re: Samsung Syncmaster S23A550H no video on VGA

Quote:
Originally Posted by tibimakai View Post
The S27A350H had the same issue, with the Check bable on the screen, and by doing the firmware upgrade through VGA cable, it works great now.
I had to install a driver first. I couldn't find the software on the US site, I found it on the Canadian site.
Don't you just looove simple solutions like these?
I did leave the reflashing software installed on my laptop, though, just in case the firmware decides to go belly up again in the future.

Quote:
Originally Posted by tibimakai View Post
Maybe the other 23" monitor, had the same issue and I have changed the mainborad.
As you basically have nothing to lose on this monitor, I'd just give it a try and reflash the 23" firmware. Keep in mind that Samsung released software versions for each individual model, so it's safe to say you can't use the software for the 27" monitor to flash the 23" one. I don't know if this can possibly brick your monitor, nor if the software is actually intelligent enough to do a check and prevent this. Better safe than sorry...

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Old 05-11-2013, 09:21 AM   #18
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Smile Re: Samsung Syncmaster S23A550H no video on VGA

The 23" it's already sold. I will sell the 27" too. I alredy have a 27" at my workbench.

Last edited by tibimakai; 05-11-2013 at 09:25 AM..
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Old 05-20-2013, 08:42 PM   #19
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Default Re: Samsung Syncmaster S23A550H no video on VGA

Much obliged for this tutorial, all!

Doing the flash routine (after locating an HDMI wire and a laptop with the port) brought the display back to life.

I want to report a couple of things:

1) My S23A550H wasn't working in either VGA or HDMI and works great after downloading the exe, restarting the laptop and flashing via VGA (!).

2) I was able to locate the exe on samsung.com by navigating the menus to let Samsung pull the model #; here's the url for future reference: http://www.samsung.com/ca/support/mo...lDownload=true

Cheers!

Last edited by jetpowercom; 05-20-2013 at 08:43 PM..
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Old 05-21-2013, 12:16 PM   #20
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Default Re: Samsung Syncmaster S23A550H no video on VGA

Quote:
Originally Posted by tibimakai View Post
The 23" it's already sold. I will sell the 27" too. I alredy have a 27" at my workbench.
Is there any guy around the world that still feels happy with a 17 inch?


To upgrade a monitor is only needed a pc? No special cables?
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