samsung syncmaster 460p black screen

[badandy]

Hello all,

I came across a syncmaster 460p that has a black screen (no backlight and I tried using a flashlight in a dark room and cannot see an image).

It seems to power on fine--pressing the power button gives one click from the power supply and the power light is a steady green.

I pulled the back cover off and gave a quick inspection of the power board and logic board and nothing stood out.

Im hoping this is the right Forum for this display since the device has dvi/d-sub/bnc connections.

Thank you in advance for any help.

[Jasgriff]

Re: samsung syncmaster 460p black screen

When you did the flashlight test did you have your PC connected?

Does the screen not come on at all not even for a split second?

Can we have some decent pics of the tops and bottoms of both boards added through the manage attachments option please.

[badandy]

Re: samsung syncmaster 460p black screen

Jasgriff,

I did have the PC connected via d-sub. I turned the monitor on while connected and cycled the source button 10 times waiting 20 seconds each time.

There is zero activity from the screen when turning it on. Just the click and the power light on steady, which I compared to another identical monitor and it is the same.

As far as pics, this display is still at work so I will be posting pics when I bring it home early next week (I dont have room at work to completely disassemble and photograph/test the boards)

Thanks

[Jasgriff]

Re: samsung syncmaster 460p black screen

K,

When you get it back we need some good pics.

Would say you need to start off with the basics. Check the big fuse then all of the less obvious smd ones. If they all test OK then you will need to test the big filter cap and see if you are getting power there.

I'm sure we can help you get it going when you bring it home.

[retiredcaps]

Re: samsung syncmaster 460p black screen

I came across a syncmaster 460p that has a black screen (no backlight and I tried using a flashlight in a dark room and cannot see an image).

It seems to power on fine--pressing the power button gives one click from the power supply and the power light is a steady green.

A steady green power LED indicates the power supply and logic board are likely working properly. If you have a source hooked up with no backlight, then it could be

a) open fuse on the inverter board
b) shorted transistor or mosfet on the inverter board
c) bad caps providing unstable or bad power going to inverter section

I would start with b).

[badandy]

Re: samsung syncmaster 460p black screen

I am having some issues uploading my photos but I managed to get two uploaded where I have circled a bulging cap. I am going to retake some my photos tonight as some were a littly blurry. All of the boards look fine with no signs of arcing/shorts.

The caps on the power and driver board seem to be made up of capxon and rubycons.

I will update once I get better photos.

[selldoor]

Re: samsung syncmaster 460p black screen

As you say the pictures are poor and too small They need to be as near to 2mb as you can get as per retiredcaps post above. The Big Caps seem to be Samyoung which is not brilliant but they are probably ok Capxon tend to fall into the replace on sight category.
The rubycons are usually ok but if they are old and have been subjected to a lot of heat
(near/under heatsinks) they will dry out.

Please can you update your profile with country and voltage..

[retiredcaps]

Re: samsung syncmaster 460p black screen

I have circled a bulging cap.

Replace just that cap first and retest. One bad cap will be enough to stop the entire TV from working properly.

[badandy]

Re: samsung syncmaster 460p black screen

Replace just that cap first and retest. One bad cap will be enough to stop the entire TV from working properly.

My pics didnt do that bulging cap justice, it is really domed at the top so I will work on getting ahold of the replacement part. Do you have any recommendations on brand?

[Jasgriff]

Re: samsung syncmaster 460p black screen

Panasonic are good in most peoples opinions.

[badandy]

Re: samsung syncmaster 460p black screen

I replaced the cap that was bulging and no-joy same as before.

[retiredcaps]

Re: samsung syncmaster 460p black screen

Post a clear focused picture of your inverter board.

[badandy]

Re: samsung syncmaster 460p black screen

I have attached some photos of the boards, I wanted to clarify that it looks like this monitor has left and right inverter boards and there is an A and B board on each side (dsc02913).

They are a PITA to remove so if we could trouble shoot the power supply first before removing the inverters, that would be great.

Just let me know if I need to post any close ups / certain parts of the boards as I figured out my issue in uploading photos, Thanks to all!!

[budm]

Re: samsung syncmaster 460p black screen

I can tell that there are at least 3 fuses on the the inverter board since I can see F3 in one of your Inverter picture, so there may be more. Look for Fxx and check the resistance of the fuses.

[badandy]

Re: samsung syncmaster 460p black screen

Thanks Budm, I will check those tonight.

the photo is of the left side inverter boards if you are facing the screen

If those fuses or even a fuse on that side were bad, would that cause both sides to not power on?