Samsung SA850 screen flashing/lines/not switching on

[rash.m2k]

Hi All,

I've got this monitor and of course it is not working.

it has a seperate power supply, so it can't be that.

The screen flashes on, stays on for a few seconds then goes off. The power led is constant though. It could be that the actual power supply is 4A and I only have a 3A one (going to buy a 4A soon).

But that doesn't explain the lines down the screen.

Hoping someone can help me fix this or happy to send it to someone to fix it for me! (in the UK)

Given these as links as the images are very high res:

https://farm6.staticflickr.com/5575/...5f005db8_o.jpg
https://farm6.staticflickr.com/5570/...0880e94d_o.jpg
https://farm4.staticflickr.com/3917/...259706b0_o.jpg
https://farm4.staticflickr.com/3852/...845870f5_o.jpg

[selldoor]

Re: Samsung SA850 screen flashing/lines/not switching on

Just a few problems with your post
1 Please can you update your profile with country and mains voltage.
2 Pictures tell little - what lines down the screen?
Reduce the size of your pictures to less than 3mb jpg and you can post them using manage attachments. You need to post one of the Led driver board if there is one and also report the voltages on the socket with the black and 1 blue wire with respect to ground. Find and test any voltage regulators.

See 2 seconds to black guide sticky at top of this forum ( mainly for ccfl backlights but has lots of useful tests start at post19)

[rash.m2k]

Re: Samsung SA850 screen flashing/lines/not switching on

Just a few problems with your post
1 Please can you update your profile with country and mains voltage.
2 Pictures tell little - what lines down the screen?
Reduce the size of your pictures to less than 3mb jpg and you can post them using manage attachments. You need to post one of the Led driver board if there is one and also report the voltages on the socket with the black and 1 blue wire with respect to ground. Find and test any voltage regulators.

See 2 seconds to black guide sticky at top of this forum ( mainly for ccfl backlights but has lots of useful tests start at post19)

Dude! Where abouts in Lancashire are you? I'd be happy to drop it off to you can pay for your services!

[selldoor]

Re: Samsung SA850 screen flashing/lines/not switching on

Heheheh - I have enough problem machines of my own !!- need to see the picture of the lines down the screen - I suspect it is going to be a bad panel so probably a waste of time trying to fix the rest.

[rash.m2k]

Re: Samsung SA850 screen flashing/lines/not switching on

heres a pic of the lines mate and the voltages too.

[selldoor]

Re: Samsung SA850 screen flashing/lines/not switching on

" Car repair man intake of breath" Fsfsssssssssshs.
Doesnt look good - does it always appear in the same place?
There will be a cable goes to the panel from the main - LVDS
If that is removable try removing cleaning and replacing.

[rash.m2k]

Re: Samsung SA850 screen flashing/lines/not switching on

" Car repair man intake of breath" Fsfsssssssssshs.
Doesnt look good - does it always appear in the same place?
There will be a cable goes to the panel from the main - LVDS
If that is removable try removing cleaning and replacing.

Fortunately no its not in the same place, cleaned contacts no luck, I've got a video i'm uploading now. It flashes a few times first then comes on and I can see the lines moving across the screen.

ok here is the video:

https://app.box.com/s/z4ilsnvm3u6sqk5if49t

[selldoor]

Re: Samsung SA850 screen flashing/lines/not switching on

Hmm - does it have a tcon or is it all on the one board does that metal cover come off
easily?

[rash.m2k]

Re: Samsung SA850 screen flashing/lines/not switching on

Hmm - does it have a tcon or is it all on the one board does that metal cover come off
easily?

tcon board - yes (if I understand you correctly) it does have one and the connectors are soldered on to the display.

The metal cover does come off, but would need to be de-soldered.

[selldoor]

Re: Samsung SA850 screen flashing/lines/not switching on

perhaps a picture of the tcon? panel board might yield some clues.

[rash.m2k]

Re: Samsung SA850 screen flashing/lines/not switching on

perhaps a picture of the tcon? panel board might yield some clues.

See attached, I also have images that are taken closer so you can make out more detail (>2 of course)

[rash.m2k]

Re: Samsung SA850 screen flashing/lines/not switching on

Ok, I've done some more tests. Tried a DVI connection and the monitor is detected and the screen changes from black to all blue which white/grey/possibly other colours lines - and I can see a vertical think white/grey bar which moves across the screen when I move the mouse (so must obviously be the mouse pointer).

The USB ports also work (plugged in my phone to charge).

I suspect you may be correct in that the Tcon board could be faulty - if a component on the tcon board can be replaced easily thats fine, otherwise I may be screwed

OK I've switched it on and two chips get very hot, I accdently touched it, one of them reads as E7=DL AOB (unsure if zero or O between) and the other reads 17814HS P247NFH (3 of these in total and the others don't get hot)

[selldoor]

Re: Samsung SA850 screen flashing/lines/not switching on

Ok - well at least the fuse is working
There is a voltage regulator on there, near the fuse - U??? perhaps test that if its supply ing an off voltage perhaps other items are overworking (heating) to compensate.
I thought I found something about the 17814HS but got distracted and lost it.
Perhaps a picture of it and the other you mention?
That mini hotair blower seems to be a medical gadget - I posted a link in the other thread.

[rash.m2k]

Re: Samsung SA850 screen flashing/lines/not switching on

Yeah - I thought I saw something about the 17814HS on the polish forums, but nothing concrete.

Where is the voltage regulator? Is it the black component below the ribbon connector on the left? And looks like like this but a bit has no screw hole? http://m2.uxcell.com/photo_new/20110...x0169_ux_c.jpg.

Ok so reading from left to right (and upside down as in the picture above), the voltages are
4.58 ==== 3.287 ==== -1.7

And the big tab is 3.287v

Be easier if I just brought it to you?

[selldoor]

Re: Samsung SA850 screen flashing/lines/not switching on

Yes I think you have the right one - IC3 - what is the part number on it?
I have never heard of one having a negative voltage? or is it just 1.7

Ok see picture now it is one of these
http://www.richtek.com/download.jsp?...RTOTE2NEMtMDND

So output is correct. 3.3v

[rash.m2k]

Re: Samsung SA850 screen flashing/lines/not switching on

Yes I think you have the right one - IC3 - what is the part number on it?
I have never heard of one having a negative voltage? or is it just 1.7

Ok see picture now it is one of these
http://www.richtek.com/download.jsp?...RTOTE2NEMtMDND

So output is correct. 3.3v

Nope, it's definitely negative 1.7, if I connect the multimeter legs the other way round it becomes positive and the others become negative.

Also there are marks on the plastic film on underside metal cover of the tcon board (I can remove them by rubbing it), they are directly above the chips that I said get hot (just to the left of the ribbon cable)

[selldoor]

Re: Samsung SA850 screen flashing/lines/not switching on

Ok - looks like we are stuck less we can find datasheet - nothing at all for the other one

[rash.m2k]

Re: Samsung SA850 screen flashing/lines/not switching on

Ok - looks like we are stuck less we can find datasheet - nothing at all for the other one

Yeah, aren't even able to buy the component!

But I've checked the voltage on the corner pin and it's almost zero (0.19mv) on the one that gets really hot, same pin on the other two ICs register at 4.6/7v.

Similar thing for the other corner pin, 1.something volts vs 4.6v.