Grumpy new monitor

[AlanHo]

I have just taken delivery of a new 20" Samsung widescreen monitor to replace my 17" LG LCD screen.

I installed it using the same power and digital cables from the old monitor and all seemed well at first - but after about 15 minutes of use, the screen kept going off (black) for a few seconds then coming back on for a few seconds ad-infinitum. The previous screen had performed faultlessly so I assumed the new monitor was faulty.

I possibly shouldn't have done this - but I put the old screen alongside the new one and hot swapped the DVI cable when the new screen was flickering - to find that the old screen did the same. Thus giving me the impression the computer was at fault. However, on reboot, the old screen was stable - but when I hot swapped the cables to the new screen it came on with the wrong resolution (the computer thought it was a 4:3 ratio screen) - when I reset to 1680 x 1050 resolution the flickering problem returned. The use of the word "flickering" might be misleading - the screen actually cycles on and off every few seconds but not consistently. Sometimes it will stay on for a minute or so before flicking on and off.

I then tried the analogue connection which required me to install the appropriate Samsung driver - and it is perfectly stable - not any sign of a problem.

The graphics card is a new Radeon Sapphire 1550 with 512 MB memory which in theory is adequate for the monitor resolution of 1680 x 1050 - but the monitor seems to behave if I set the resolution much lower. My local friends have older computers with lower spec graphics cards so I am not easily able to try the monitor on another computer.

Hence my dilemma - do I send the monitor back as faulty because of the digital connection problem and risk the supplier not finding a problem and claiming it is my computer. Or do I shrug and continue to use the analogue connection which appears OK.

[-pops-]

I'm a recent convert to TFT screens and I've found the digital connection a total nuisance on all three of my machines. I've had them not working at all, working intermittently and the other one failing after about half an hour. On the old analogue connection they all work perfectly OK. I'm not bothering any more with the DVI connection.

[Raddy]

There are some high-end monitors that require a different kind of DVI than is traditionally found on consumer level video cards (I think it's called DVI-I or something like that). I had a friend who had a pair of 19" Viewsonics and was unable to use the DVI because he had two 6800 GTXs and for whatever reason they didn't produce the correct DVI signal. When he upgraded to a high-end workstation video card, the DVI worked just fine.

In short, it may just be that you need a workstation card as opposed to a consumer card.

[-pops-]

Raddy, you are probably right in that - or it's something very similar.

My three machines are a couple of years old and, from what Alan said the other day, his machine is not new either.

I would have been better, though, for the monitor manufacturer to make it more obvious that this was so.

I am certainly not going to upgrade my graphics cards, my machines are just not worth the expense of that so I'm sticking with analogue.

[AlanHo]

For the record - my computer tower casing and some of the innards are oldish - but I have just had it upgraded with a new motherboard, Intel duo processor, SATA twin drives and the Radeon Saphire 1550 graphics.

Following the DVI train of thought - my graphics card has a DVI-I socket and the new monitor has a DVI-D socket. The cable provided with the monitor has DVI-D plugs at both ends.

From what I understand from some googling, the DVI-I socket has four extra pins to carry an analogue signal - whereas the DVI-D socket is purely digital. I also note that you can buy cables with DVI-I at one end and DVI-D at the other. It looks like you can plug a DVI-D plug into a DVI-I socket if you don't require the analogue connection - but not the other way round.

My old LCD monitor also has a DVI-D socket and worked OK with the DVI-D cable - so could this really be a problem.

On the Samsung support website the following information appears in the FAQ's :-

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Question.......My monitor has an DVI-D port and the Graphic card on my computer has a DVI-I port. What cable should I used to ensure that the signal is digital?

Answer.........You can purchase a DVI-D to DVI-I cable that should work with your setup.

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A separate question states......

Question.......What DVI Cable Do I Need For My Samsung DVI Compatible Monitor?

Answer.........All current Samsung monitors that are DVI compatible have DVI-D (Digital) Single Link input ports. You can connect the DVI-D Single Link input port on your monitor to a video card that has either:

A DVI-D Single Link output port

A DVI-I Single Link output port

To connect them, you can use either:

A DVI-D Single Link cable

A DVI-D Dual Link cable

You cannot use a DVI-I (Integrated Digital and Analog) or DVI-A (Analog) cable.

Note: Most Samsung monitors with DVI input ports are both digital and analog compatible. Analog compatibility is provided by a 15 pin D-sub analog video input port. If you want, you can connect both the digital and analog ports to your computer and use either one or the other. On most monitors, you use the Source button to select between digital and analog.

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Frankly I don't understand it.

[andsome]

No problem using the analogue connection. The digital connection was put straight into the cupboard when my monitor arrived.

[AlanHo]

I have now determined the monitor is faulty.

I spoke to Samsung UK support and discussed the symptoms - they concluded it was most likely a fault in the monitor's digital circuit but advised me to check the monitor on a second computer to verify.

I therefore took it to a friend who lives 25 miles away - but he has a computer of similar spec to mine (better in fact - he is heavily into gaming with high end graphics). On his computer the monitor starting playing up after about 10 minutes and then went off. It came on again after a couple of seconds, stayed on for about 20 seconds and repeated this cycle....... This differs from my computer where it flashes on and off every second or so.

Intrigued by this difference - we trotted off to a friend of his who tried it on his computer. Here the monitor again played up - but the behaviour was different again. It took about 20 minutes before it went off - was off for about 10 seconds - then started flashing on and off every 5 seconds or so.

I have therefore proved there is a problem with the DVI connection to the monitor but cannot understand why it varies when connected to different computers. I appreciate that I can use the analogue connection - but am hesitant to retain a product with a fault in case it "spreads" to the analogue circuit.

Back to the supplier on Monday....

[Raddy]

You paid for a digital monitor, there is no reason you should settle for analog. I probably haven't had as many monitors as some of the these other guys, but I've personally never had an issue with DVI. Ship it back.

[AlanHo]

I returned the faulty Samsung monitor and have replaced it with an LG 22 6WTQ which has connected with the DVI cable without a problem.

Anyone looking to buy a 22" monitor should include this LG model in their list for consideration alongside the Samsung equivalent - both have superb displays.