I've just bought a second-hand Sony GDM-W900 24" CRT computer monitor and it's great apart from 3 very thin lines (red, green and blue) which run at about a 4 degree angle downwards from right to left then continue horizontally from left to right (but much fainter), in the bottom third of the screen. They are there at all resolutions and I have tried adjusting every setting in the menu to no avail.
I know about the damper wires but I've seen those. These are about the same thickness but at a slight angle and coloured. I found out how to do a monitor self-test (with no leads) and the lines are there. With no input they flicker up and down the screen so it's nothing to do with the input but a monitor fault unfortunately. I've also tried tapping the screen, degaussing etc.
Is there any hope?

The best information source/forum on the FW900 is probably the Hardforum thread. The site is down right now, but you can visit the thread later:

http://www.hardforum.com/showthread.php?t=952788

That problem doesn't sound familiar to me, though. It it maybe a convergence problem?

This problem can be solved via Sony WinDAS software. You'll find more information in the thread that GreenMonkey linked. I think the setting you need to change is G2. Should be good as new after that.

It does sound like G2 "retrace" lines. An adjustment may fix it or you may have some sort of failure in the hardware of the device. Does the picture looked washed out? Usually over driving the G2 which will cause these lines, will also wash out the picture.

The picture looks great - not washed out at all. I have the Win DAS software now - all I need is a cable. There is a socket at the back marked 'Service' but I suppose that would require an impossible-to-find Sony cable.

I have opened up the monitor and found a module with 2 screws both of which seem to affect focus. On the tube itself is a large grey module with large wheels to adjust: TLH, APH, XCV and XBV along with screwdriver adjustable YBH, YCH and TLV. Any idea if one of these affects the G2 I don't really want to start fiddling around with them in case I damage something or do something I can't correct.

You probably need to dig up the service manual for your monitor on the Web I know it is out there because I saw it when looking for the manual for my older GDM-W900 monitor. You do NOT want to go twiddling knobs without knowing what you are doing. I have adjusted G2 on my CRT projector before and it is real easy with the instructions (which will vary from device to device). Also it is unusual for G2 to get too far out of whack unless somebody has fiddled with it, there is a failure or the hours are crazy high on your monitor.

Since you just purchased it can you return it for another one or get a refund?

You probably need to dig up the service manual for your monitor on the Web I know it is out there because I saw it when looking for the manual for my older GDM-W900 monitor. You do NOT want to go twiddling knobs without knowing what you are doing. I have adjusted G2 on my CRT projector before and it is real easy with the instructions (which will vary from device to device). Also it is unusual for G2 to get too far out of whack unless somebody has fiddled with it, there is a failure or the hours are crazy high on your monitor.

Since you just purchased it can you return it for another one or get a refund?

That's the monitor I have. Do you have the manual still or a link? I haven't managed to find it myself.

Sadly I bought it on eBay. I haven't given any feedback yet - I don't really want to ask for my money back yet as it may be repairable.

This may apply to your monitor
Problem: Sony Trinitron monitors with brightness too high. Also affects Multiscan G420 monitors and Trinitrons rebadged as Sun monitors.

The screens on Trinitron-based Video Display Units / CRTs get brighter as they age. There is no Sub-Bright adjustment on these units, and they get to the point where the front panel brightness adjustment is set to zero, and the screen is still way too bright (blacks appear as grey). In extreme cases the retrace lines are clearly visible.

Solution:

Multiscan G420:
1. Set screen brightness control to some middling value (say, 50-70%).
2. Make sure colour mode is set to "preset", "easy", or "expert". This is done by pressing the menu button, and navigating to the toolbox icon, and then the "3-dots" icon.
Once done, return to the main menu.
3. Navigate to the "three dots" icon (a different one from step 2, above) and then the "head-and-shoulderpads" icon.
This is the "image restoration" menu. This function will only be available if the screen has warmed up, which takes about 30 minutes.
If it's not warmed up, this menu selection will state, "Available after warm up", in which case, you'll just have to wait, making sure the screen doesn't turn off in powersave, or screensaver mode.
Once warm, you can select "yes" to start the auto-calibration process. This takes a few moments while it samples different settings.
4. Brightness can now be set as desired.


Sun Trinitron displays:
These are much the same, but have a different menu structure, and button interface, but the icons are essentially the same, and the "head-and-shoulderpads" icon is entitled "colour return".
BAP

Brett Preisig
John Reynolds

May 2005

Are you sure you have the GDW-W900, that is an older monitor with a curved screen. Mine was made in 1997 and is still working great. Based on what Roland posted I guess these tubes do age like that, that is pretty interesting. Any way it is your lucky day if you have a fw900 because it looks like my Service Manual is for the FW-900 not the W900 (so much for my memory). You can get it here (http://rapidshare.com/files/107716171/SONY_GDM-FW9012_G1W.pdf.html). It is too big to post on AVS. I hope it helps.

Yep - W900 ,made in 1999 and looks fine (apart from those *%*^$*% lines!) - no brightness problem at all. I wonder how similar my W900 is to the FW900 - probably completely different knowing my luck. On another forum someone has pointed out a high voltage pot (RV901) in the Deflection block in the circuit diagram of the FW900. If the 900 has the same circuit board, could this be what I need to adjust. If so, is it safe to do so or am I going to end up the other side of the room if I touch it with a screwdriver (I've had enough electric shocks in the past - not an sensation I enjoy)?

Update: a company called Seme Nedis Ltd sells the 'monitor to PC interface cable' here in the UK for £33. I shall buy it and see if I can fix the problem. After that, if any W900 owner wants to buy it off me they'll be welcome to.

Update: a company called Seme Nedis Ltd sells the 'monitor to PC interface cable' here in the UK for £33. I shall buy it and see if I can fix the problem. After that, if any W900 owner wants to buy it off me they'll be welcome to.
Sony GDM-90w10 owner here. Manufactured in 1998.

I've taken apart my monitor to look for a variable resistor on the D board. The monitor has boards on each side that open out like wings. It is pretty cool. My monitor's problem is that the screen is too dim (even at 100% brightness via on-screen controls). I'm at the end of what I can do with software compensation (in addition to the OSD).

The interesting thing is that as the tube warms up, the brightness smoothly and slowly goes up and down up and down up and down until it stabilizes somewhere towards the dim side. I'm guessing it is an automatic voltage regulation that was doing it (I saw what appeared to be that feature on the schematic).

But variable resistor? Darned if I could find one. I tried pretty hard. No such beast that I could find.

BTW: Let me know how that service cable goes. I'm really interested.

Sony GDM-90w10 owner here. Manufactured in 1998.

I've taken apart my monitor to look for a variable resistor on the D board. The monitor has boards on each side that open out like wings. It is pretty cool. My monitor's problem is that the screen is too dim (even at 100% brightness via on-screen controls). I'm at the end of what I can do with software compensation (in addition to the OSD).

The interesting thing is that as the tube warms up, the brightness smoothly and slowly goes up and down up and down up and down until it stabilizes somewhere towards the dim side. I'm guessing it is an automatic voltage regulation that was doing it (I saw what appeared to be that feature on the schematic).

But variable resistor? Darned if I could find one. I tried pretty hard. No such beast that I could find.

BTW: Let me know how that service cable goes. I'm really interested.

I had an old Viewsonic that did that, and my beloved NEC 21" is now doing it too. I'm not adventurous to try and repair it, though.