Samsung 305T - Video Distortions

[nosmoking]

Re: Samsung 305T - Video Distortions

hi,
I haven't taken the panel apart,I did email a bunch of people that should know if it's the panel ,they said it was inside the panel ,but would you tell some more about the inside of the panel and is it fixable or is it replacement time,
If you are having other problems the voltages are listed aroung the plugs on the boards ,if you have a volt meter you can check these ,they should be real close to what is written on the board,a Rat shack meter will do this if you don't have one.
Those spots on the boards that are changing color are hot spots,I got a kit off ebay for all the electrolytic caps,and replaced them,mine had 2 rubycon and the rest were samyoungs I checked the first 8 with a caps testor they were out of spec so I replaced all of them,I did notice the icons/colors were much sharper after the caps were changed,
I did try to reflow the Tcon board ,The oven is the eziest the heat gun has got to keep moving and don't bump the other parts on the board as they will move and you don't want that to happen,I took some heatsinks off of old mother boards and JB welded them to the altera chip and a few around it,I got 2 fans from old computer power supplies,and used a 9volt power supply (wall plug in style),These fans must be wired red wire to plus and blk to negitive or they won't run ,I put one fan over the altera board and one at the top of the power supply board,I use quick dry bathtub silicone and boxed the edges with plastic to make the fan fit the metal where the vent holes are,It now runs very cool,

[budm]

Re: Samsung 305T - Video Distortions

Hmm, I never seen the polarizer sheet with 1 pixel wide strip in any of the LCD screen I took apart (hundreds), all of them (polarizer sheets are mounted behind the LCD panel) are the same size of the LCD screen.

[Jag U. Ar]

Re: Samsung 305T - Video Distortions

The polarizer is a sheet of one pixel wide strips bonded together and damage to it can look like vertical lines. Unfortunately, there's really no way to fix that yourself.

[severach]

Re: Samsung 305T - Video Distortions

Are you saying that computer displays have a vertical line but OSD displays do not?

[jetadm123]

Re: Samsung 305T - Video Distortions

hi ,
I am new here and probably for the same reasons 305T ,lol.
I have replaced all the electrolytic on all the boards and replaced the logic board with the famous chip altera I still have one, one pixel wide light green line,running from top to bottom almost in the middle of the screen,This monitor got dropped but owner said he caught before it banged on the floor,the self check looked ok ,no line but I put 2 new logic boards in it and I still have the line,I have checked all the voltages around the cards they are right on,checked plugs at top of screen and on all boards while watching,nope still my line is there ANYONE have this any suggestion would be helpful.I haven't re flowed the new board yet.....and I did rob 2 old power supply fans and square heatsinks form old mother boards to put on the altera and other chips that were rather warm,the fans did make a big difference in hot to cold air and it's just warm on the back now not hot,
Thanks alot !!!!!!! https://www.badcaps.net/forum/images/smilies/cheers.gif

I'm inclined to think that it's more of a panel problem rather than any of the boards. There is a LCD electronics panel/control board that should span the width of the LCD panel. From this board there are a series of flat ribbon cables that connect the panel board to the LCD panel. Failure of the bonded connection between the cable and board will generally cause lines on the screen. You can try gently pushing down on the connection with your finger to see if that solves your problem.

[nosmoking]

Re: Samsung 305T - Video Distortions

hi ,
I am new here and probably for the same reasons 305T ,lol.
I have replaced all the electrolytic on all the boards and replaced the logic board with the famous chip altera I still have one, one pixel wide light green line,running from top to bottom almost in the middle of the screen,This monitor got dropped but owner said he caught before it banged on the floor,the self check looked ok ,no line but I put 2 new logic boards in it and I still have the line,I have checked all the voltages around the cards they are right on,checked plugs at top of screen and on all boards while watching,nope still my line is there ANYONE have this any suggestion would be helpful.I haven't re flowed the new board yet.....and I did rob 2 old power supply fans and square heatsinks form old mother boards to put on the altera and other chips that were rather warm,the fans did make a big difference in hot to cold air and it's just warm on the back now not hot,
Thanks alot !!!!!!! https://www.badcaps.net/forum/images/smilies/cheers.gif

[Jag U. Ar]

Re: Samsung 305T - Video Distortions

Thanks everyone who posted in this thread, the info here showed me how to repair my 305T.

I was getting wavy patterns and flickering. Putting the main logic board in the oven at 400 degrees for 10 minutes fixed me up. I hadn't seen that trick before so I'm quite happy about finding it.

To provide more cooling I cut a pair of holes out of the back cover, one above the logic board and the other above the other hot spot, and glued 80mm usb fans in place. Used the monitor's hub for power, of course. Wiring a 3 or 4 pin fan to a usb cable is easy enough but I went ahead and bought a pair of fans from coolerguys on amazon. The difference in temps with the fans is really dramatic so we'll see how it holds up.

I had this monitor next to a new HP with an IPS panel just today and the 305T's image is still quite competitive. Samsung really did a great job on the image quality, too bad they came up short on the cooling.

[severach]

Re: Samsung 305T - Video Distortions

I used double sided thermal tape to stick the heat sink on. The tape doesn't stick that well so I ground the tips off the heat sink so the frame bar would keep it pressed on without breaking the solder points. The tape is enough to keep it from creeping.

When I saw how expensive heat sinks were I started grabbing them off everything. This heat sink was off a Samsung TV scaler board.

[les_garten]

Re: Samsung 305T - Video Distortions

I didn't want the fans to run all the time but I wanted to ensure there was no chance that the fans wouldn't run any time the T-Con board is running. The UP2202T-01P power supply provides 24v and 12v. The inverter runs off 24v but I couldn't find any power switched with the monitor. Interfacing with BLON would require a MOSFET driver and I'd like to avoid active components and circuits. The T-Con display driver board is supplied with 3.3v and 18v and both are switched on and off with the display. I decided that 2 12v fans in series running on 18v would run them at low speed to keep the noise down. I mounted two standard ATX power supply fans and wired them in series. They were quite noisy. I decided that was due to the dirty power draw of DC brushless fans so I placed 470uf 25v capacitors across each fan which cut the noise. Now when I run my hand across the top of the monitor the case is cool where the fans are. The rest of the monitor stays much cooler than it used to.

The circuit is simple: two fans in series to 18v, a cap across each fan also in series.

The fans mount to a frame member with one screw per fan so they can rotate for minimal interference to assembly. The pictures show them rotated out to allow the RF shield to be put on. Then they rotate together against the shield.

The XHD3000 has two other problems.

All white screens have a light flicker which resembles tube monitor interlace flicker. I can't tell if this flicker is the back light varying in brightness or the image processor has trouble with large patches of one color. Sometimes all white screens will have short periods where there is no flicker.

Shortly after startup from sleep the screen will flash black one time. If it flashes black a lot or shows a distorted picture the cable is bad. There are a lot of bad dual link DVI cables available.

Hi,
I'm workin' my XHD3000 problem. Did you use "Thermal Glue" on the heatsink on the Altera chip? Did you heat sink the other chips on that board as well? Was the heat sink just something you had laying around?

Regarding the Fans, do the Ext. USB ports run power all the time? I'm a little worried about the Fans drawing on that Board if the fan starts to draw high current from impending failure.

Thanx!

[les_garten]

Re: Samsung 305T - Video Distortions

Page 9-7 has the schematic with the part values. In this specific case, the important parameters are 1) capacitance. example 2200uF 2) the working voltage. example 35V 3) the package dimensions - height, diameter, and 4) the pitch - this is the distance between the pins. Obviously the right value in a package that is too big to fit isn't going to be much good. I will check back and post the digikey part values I used if anyone is interested.
.

@Ian, can you post the digikey parts list? I need to do this as well.

[severach]

Re: Samsung 305T - Video Distortions

My reballed XHD3000 lasted about 2 months so heat is the problem and magic solder won't fix it. Through unfortunate circumstances I bought a used T-Con board and this time I added a fan mod. I have no idea how to fit fans into the Samsung 305T but 2 80mm ATX fans, two capacitors, and some wire fits very well in the Gateway XHD3000. The fans are quiet and completely automatic. I cut a hole in the metal frame case and added a real heat sink. I wanted the fans to mount reliably yet minimally interfere with monitor assembly.

I didn't want the fans to run all the time but I wanted to ensure there was no chance that the fans wouldn't run any time the T-Con board is running. The UP2202T-01P power supply provides 24v and 12v. The inverter runs off 24v but I couldn't find any power switched with the monitor. Interfacing with BLON would require a MOSFET driver and I'd like to avoid active components and circuits. The T-Con display driver board is supplied with 3.3v and 18v and both are switched on and off with the display. I decided that 2 12v fans in series running on 18v would run them at low speed to keep the noise down. I mounted two standard ATX power supply fans and wired them in series. They were quite noisy. I decided that was due to the dirty power draw of DC brushless fans so I placed 470uf 25v capacitors across each fan which cut the noise. Now when I run my hand across the top of the monitor the case is cool where the fans are. The rest of the monitor stays much cooler than it used to.

The circuit is simple: two fans in series to 18v, a cap across each fan also in series.

The fans mount to a frame member with one screw per fan so they can rotate for minimal interference to assembly. The pictures show them rotated out to allow the RF shield to be put on. Then they rotate together against the shield.

The XHD3000 has two other problems.

All white screens have a light flicker which resembles tube monitor interlace flicker. I can't tell if this flicker is the back light varying in brightness or the image processor has trouble with large patches of one color. Sometimes all white screens will have short periods where there is no flicker.

Shortly after startup from sleep the screen will flash black one time. If it flashes black a lot or shows a distorted picture the cable is bad. There are a lot of bad dual link DVI cables available.

[TikiMan098]

Re: Samsung 305T - Video Distortions

I will check back and post the digikey part values I used if anyone is interested.

Can you please post the digikey parts list you used?

Many thanks,
-Adam

[jetadm123]

Re: Samsung 305T - Video Distortions

hello
After months having like a haze in front of my eyes, my Smasung 305 T+ died last week, symptoms :
- vertical + horizontal colored lines
- full frame flikering, like a stroboscope.

I first changed all the caps on boards but this has not been very effective.
so i looked around the web to found any information about the differents boards. finaly i found this thread about Gateway HXD3000 witch has quite the same design

http://hardforum.com/showthread.php?t=1527751

And with the help of a heat gun I managed to fix my screen !!

all this is about the Altera chip...

hope this will help you fix your own screen !

best regards

edit : sorry Muratus i have read your post afterwards... by the way i have found the same method

Glad that it worked! The only problem I see is that excess heat was the original cause of the problem and that it's only a matter of time before the problem occurs again. I think severach had a similar issue and he attached a fan to the case for additional cooling. Perhaps he can chime in and share what type of fan he used and how he mounted it.

[flyone]

Re: Samsung 305T - Video Distortions

hello
After months having like a haze in front of my eyes, my Smasung 305 T+ died last week, symptoms :
- vertical + horizontal colored lines
- full frame flikering, like a stroboscope.

I first changed all the caps on boards but this has not been very effective.
so i looked around the web to found any information about the differents boards. finaly i found this thread about Gateway HXD3000 witch has quite the same design

http://hardforum.com/showthread.php?t=1527751

And with the help of a heat gun I managed to fix my screen !!

all this is about the Altera chip...

hope this will help you fix your own screen !

best regards

edit : sorry Muratus i have read your post afterwards... by the way i have found the same method

[Ian_s]

Re: Samsung 305T - Video Distortions

OK guys. I think I can offer a bit of help based on my recent 305T resurrection and 20 years experience as electrical engineer. The short version is I replaced 1) all surface mount electrolytic caps on the logic board. This had no effect. 2) I then replaced **some specific ** electrolytic caps on the power supply board. This did work.

Going through this and other threads I see a lot of common failures that I would tackle the same way. The electrolytic caps on both of these boards are part of the power supply systems for the various boards. These capacitors are used to keep the power supply voltages stable and clean. When they fail, the power supply voltages get very noisy and have strange effects based on the power supply load, which depends on what the systems is doing ... on and on.

Bad caps = a wide range of strange symptoms and problems.

Electrolytic capacitors fail in several ways but the most common is they dry out as they get older. This happens faster in warm or heated conditions. Sometimes you can tell that one has failed just by looking, but other times you would have to take it out and test it to find the failure- not really practical. Typically if one has failed they then some others are failing or will fail soon.

Easy Solution: Replace all of them. They don't cost much. There are some less likely to be the problem like the power supply circuit on the USB hub within the monitor, but it took quite a bit of time to get this monster apart and once I was changing some of the electrolytic capacitors I just changed them all. If I was doing this again I would start with the capacitors on the output side of the SMPS power supply board. These are the caps in the "Rectifying & Filtering" section indicated in the picture on page 13-3 of the service manual. There are six of them and these ones are NOT surface mount so they are fairly easy to change.

BE VERY CAREFUL. PART OF THIS BOARD HAS 120V ON IT AN THESE VOLTAGES CAN STAY IN THE CAPACITORS ON THE "HOT" SIDE OF THE CIRCUIT. IF YOU DONT KNOW WHAT YOU ARE DOING THEN DON'T DO IT.

Page 9-7 has the schematic with the part values. In this specific case, the important parameters are 1) capacitance. example 2200uF 2) the working voltage. example 35V 3) the package dimensions - height, diameter, and 4) the pitch - this is the distance between the pins. Obviously the right value in a package that is too big to fit isn't going to be much good. I will check back and post the digikey part values I used if anyone is interested.

To sum up:
Power supply problems cause all sorts of strange symptoms. Most common power supply failure is electrolytic capacitors. They should be first thing to replace on the boards. It is exceptionally rare to have other problems with chips, diodes, transistors or any other part (maybe broken connectors) unless damaged by having the capacitors fail.

If you are not comfortable with changing parts, I would suggest ordering the replacement parts from Digikey or Mouser or similar, and taking them and the monitor to a TV repair shop and have them do it.

Good Luck.
Ian S.

[TheMinion]

Re: Samsung 305T - Video Distortions

Hi guys, i just joined the forum to thank everyone that has provided help in this thread. It helped me a lot.
Unfortunately, i own a 305T as well, and i have the same problem:
http://www.youtube.com/watch?v=oojI5...eature=related

I don't have any experience with replacing boards, but i will probably buy the board tarbender posted as well, and try to replaced it myself:
http://www.samsungparts.com/Products...0A.aspx?model=

I just have one question though. Some guys in another forum got the same problem and one guy linked this board:
http://www.suppliesnow.nl/english-pr...n81-02450a.htm

From the photos it doesn't seem like its the same board. But the names are the same. Any idea if both will do just fine?

Thanks in advance.

[tarbender]

Re: Samsung 305T - Video Distortions

I am trying a replacement board with the Altera chip that I ordered from the Samsung parts site:

http://www.samsungparts.com/Products...0A.aspx?model=

It cost me $214. I did not want to attempt the heatgun option. I need reliability for my work computer.

I have ordered some USB fans from amazon to keep it cool.

So far so good after 4 hours. I will report back with more details if it is still successful.

[iceace]

Re: Samsung 305T - Video Distortions

Hi,

Just a quick observation concerning the video distortions in my Samsung Syncmaster 305T Plus monitor:

- I have an ATI Radeon HD 4850 video card and by Catalyst Control Center I just adjusted Contrast -> 0 (range 0...200) and Brightness -> -5 (range -100...100) and after this pressed the 305T Brightness key to get the max brightness out of the monitor

=> no more distortion!

The overall brightness and contrast is not very good but I can work with the monitor till I get it fixed.

So just a temporary quick solution before trying any heating. Maybe this will work also in your 305T.

[Muratus]

Re: Samsung 305T - Video Distortions

Hey guys,

Sorry I've not updated in a long time. Just noticed that there was posts again.

I ended up reflowing the ALTERA BGA chip myself. First time I tried the heat gun method talked about here: http://hardforum.com/showthread.php?t=1527751 that lasted a few weeks.

I reflowed it a second time doing the same thing. This time I heated it longer. It held up about a month after that one.

Finally I started reading about how the guys with the HP DV9000/DV6000 laptops were oven baking their motherboards to reflow their gpu's. I ended up baking my whole board in the oven at 375F for 8 mins. That was in Jan 2011. It's been running ever since.

I did also leave the back panel off of my monitor. Then I cut a whole in the metal cover of that board, and added a BGA heat sync from a old motherboard, using thermal paste between the chip and heat sync. I then made a large plastic cover that mounts on the back of the monitor. That cover holds 3 120mm fans powered by my computers PSU. It's quite the contraption.

So really just a reflow will not do it. You need to be able to cool that chip down while it's running. If you google "305T reflow" there is many examples of people doing similar things to their monitors to keep them running.

[flyone]

Re: Samsung 305T - Video Distortions

here is the file