Most likely bad filter caps in the horizontal scan amplifier. It will most likely be a high voltage capacitor. Don't poke around CRTs unless you know exactly what you're doing. They can kill you in a split second if you let the voltage go across your chest.

When capacitors go bad, especially filter capacitors, it can cause waveforms to go wonky.
The horizontal amplifier takes the horizontal sync from the video card and scales it to fit on the screen. The signal that it puts out deflects the CRT beam from left to right, scanning the screen. It normally is a sawtooth wave, like the one in figure a. In your case, it looks like the horizontal scan is rising too high, and peaking the horizontal amplifier. This would produce the bright line at the edge, The signal in your case would look more like a sawtooth wave with a curve at the top, and flattening out. (figure b) This would cause the beam to stay in one place longer, causing a bright line.

Hope this helped you understand the problem better. Good luck on fixing the monitor!

dkarguth wrote:

Most likely bad filter caps in the horizontal scan amplifier. It will most likely be a high voltage capacitor. Don't poke around […]
Show full quote

Most likely bad filter caps in the horizontal scan amplifier. It will most likely be a high voltage capacitor. Don't poke around CRTs unless you know exactly what you're doing. They can kill you in a split second if you let the voltage go across your chest.

When capacitors go bad, especially filter capacitors, it can cause waveforms to go wonky.
The horizontal amplifier takes the horizontal sync from the video card and scales it to fit on the screen. The signal that it puts out deflects the CRT beam from left to right, scanning the screen. It normally is a sawtooth wave, like the one in figure a. In your case, it looks like the horizontal scan is rising too high, and peaking the horizontal amplifier. This would produce the bright line at the edge, The signal in your case would look more like a sawtooth wave with a curve at the top, and flattening out. (figure b) This would cause the beam to stay in one place longer, causing a bright line.

Hope this helped you understand the problem better. Good luck on fixing the monitor!

Since a few days mine has the same, although much less worse. Don't think it happens on lower resolutions though. Also the image shakes to the left and right sometimes. Is it bad for the monitor to use it with this issue? I also have a problem with lower brightness, could that also be due to a bad capacitor?

@Brachabre does it improve after letting the monitor warm up? Just curious.

I'd advise against using the monitor if it has visible distortion. Bad capacitors can generate heat, and possibly explode. This can damage other components, and in some cases, ruin the board. The shaking left and right problem is a problem in the horizontal sync section, it sounds like it's not getting a solid sync lock. Likely capacitors. That's pretty much the only thing that goes wrong with those monitors besides the occasional flyback transformer.

Could be a (progressing) short on the flyback transformer as well. Most PC monitors that are not in the "pro" category (and same goes for CRT TVs) have just one main transformer that does 3 things:
- generates HV (high voltage) for the CRT tube
- generates auxilary voltages for CRT focus etc
- generates voltages for the main PCB logic
Usually the power supply is actually pretty simple and outputs just one voltage and then the flyback is the main source of all required voltages.

Since the flyback trafo is switched by the same transistor that does horizontal sweep (and drives the horizontal deflection coil), the HV and focus are linked with scan frequency. Any problems with one with one will affect the others. On "pro" monitors you'd usually have separate horizontal sweep, separate HV and separate PSU for other CRT controls. Plus a lot of shielding so these things are heavy.

Anyway, nothing can be done with the transformer short of replacing it, and even then, even if you get a correct replacement, you still have to recalibrate the monitor afterwards. However quite often the issue is not the trafo itself but rather the solder joints - these crack due to high frequency vibration and all kinds of problems pop up. Usually the very first thing you'd do is resolder all of them with some fresh solder and flux, there is no point in looking for the crack, just go over all of them. Let the monitor sit unplugged for few hours before you start doing that, don't touch the HV wires, and use a good (at least 60W) soldering iron.

Note that CRT tubes do wear out. Eventually the cathode looses it's ability to produce enough electrons and the electronics inside the monitor can only compensate for so long. Once you get the effect of not being able to set the screen so it's in focus in both the center and the corners, the tube is done.

dkarguth wrote:

I'd advise against using the monitor if it has visible distortion. Bad capacitors can generate heat, and possibly explode. This can damage other components, and in some cases, ruin the board. The shaking left and right problem is a problem in the horizontal sync section, it sounds like it's not getting a solid sync lock. Likely capacitors. That's pretty much the only thing that goes wrong with those monitors besides the occasional flyback transformer.

Very interesting, I'd open it just to take a look but I must admit I'm a little scared to do so. It has this huge metal casing around the tube which I'm not sure of I can touch (ie to move it after the plastic casing is removed). A very friendly vogon user @ my other monitor topic Monitor very dark told me a bit about crt's and that you can adjust the voltage to increase brightness. I'm curious if something else could be bad inside the monitor that causes the brightness issue. Besides, if I take it to a repair shop I don't want them to increase the voltage to fix the brightness while it could be a bad capacitor or solder connection that I can fix myself. I"ll take your advice and stop using it for now.

Deunan wrote:

Could be a (progressing) short on the flyback transformer as well. Most PC monitors that are not in the "pro" category (and same […]
Show full quote

Could be a (progressing) short on the flyback transformer as well. Most PC monitors that are not in the "pro" category (and same goes for CRT TVs) have just one main transformer that does 3 things:
- generates HV (high voltage) for the CRT tube
- generates auxilary voltages for CRT focus etc
- generates voltages for the main PCB logic
Usually the power supply is actually pretty simple and outputs just one voltage and then the flyback is the main source of all required voltages.

Since the flyback trafo is switched by the same transistor that does horizontal sweep (and drives the horizontal deflection coil), the HV and focus are linked with scan frequency. Any problems with one with one will affect the others. On "pro" monitors you'd usually have separate horizontal sweep, separate HV and separate PSU for other CRT controls. Plus a lot of shielding so these things are heavy.

Anyway, nothing can be done with the transformer short of replacing it, and even then, even if you get a correct replacement, you still have to recalibrate the monitor afterwards. However quite often the issue is not the trafo itself but rather the solder joints - these crack due to high frequency vibration and all kinds of problems pop up. Usually the very first thing you'd do is resolder all of them with some fresh solder and flux, there is no point in looking for the crack, just go over all of them. Let the monitor sit unplugged for few hours before you start doing that, don't touch the HV wires, and use a good (at least 60W) soldering iron.

Note that CRT tubes do wear out. Eventually the cathode looses it's ability to produce enough electrons and the electronics inside the monitor can only compensate for so long. Once you get the effect of not being able to set the screen so it's in focus in both the center and the corners, the tube is done.

It's an Iiyama Vision Master Pro 514. Because I have plenty of other ones that were used a lot more, I'm not yet convinced that it's worn out. It's still sharp in every corner. It's not 'dark' as in you can't see anything, but more like it's at 70% brightness instead of 100%. I need that extra 30% to see dark areas in games or movies. And yeah it shakes sometimes, my other iiyama has the same shaking issues but is still very bright, even though it's been used more.
Anyway, this isn't my topic:) I don't want to hijack it from Brachabre 😀 Interesting though!

Significant (as in, noticable) loss of detail in dark areas of the picture is also a sign of wear. Internal circuitry monitors both the cathode current and HV value, and will raise HV to compensate for current loss (due to lowered emission). This will usually let you keep the brightness but at the cost of detail on very dark and very bright areas. But you can only safely raise HV so much before you risk producing too much gamma radiation in form of X-rays. Then there are other problems with changing CRT voltages too much, like the loss of focus.

Many CRTs will also exhibit yellowing as they age, which is the result of degradation of the blue phosphor - as blue is highest energy color and typically wears out faster. Same with LCD backlights (and that goes for LED ones as well since white color is usually blue LEDs with yellow/orange phosphor).

If the loss of brightness was sudden, and there isn't any difference in picture shape (it's not wider or narrower now) it could be contrast circuitry issue, which is related to flyback trafo but only because the voltages here are provided by it. Could be also one of the color guns degrading or shorting and the electronics trying to compensate for it while keeping the color range unaffected. In short there's a lot that can go wrong with a CRT.

You have a horizontal linearity problem and squashed raster on both sides at the same time, first thing you have to answer is whether that happens on other resolutions or 720x400 is the only one affected.

Elektrotanya is your friend.

https://elektrotanya.com/gateway_ev700.pdf/download.html

With EV700 connected to the S3 Virge DX PCI video card,I booted into windows 98se and tested all the monitor's default display modes (see table added to OP) and the verdict is 720x400@70Hz and 640x480@75Hz modes are the only two modes exhibiting this horizontal-width-not-scaling-correctly issue I'm having. However, no problem changing to 640x480@85Hz but not sure this monitor technically supports this mode even though it's listed in Win98SE adapter refresh rate settings and seems to work okay.

Display pics at various modes:

720x400@70Hz
(No pic, but we already know this mode has horiz width issue)

640x480@75Hz (start menu and clock cut off due to horiz width issue)

640x480@85Hz (Good)

800x600@75Hz (Good)

800x600@85Hz (Good)

1024x768@75Hz (Good)

1024x768@85Hz (Unknown)
(Not tested as it wasn't listed as adapter refresh rate option)

1280x1024@60Hz (Good)

Horizontal linearity problem (squashed picture on right side+increased brightness) seems to be gone at other resolutions, but squash on both sides still persists, just compare "My Documents" and "Online Sevices" folders, it's very obvious. This monitor supports 720x400 @ 70Hz by default, so you can be certain that it's 100% faulty.

You got scammed there pretty good on Ebay, now you have two options, return it (if it's worth it) or try and fix it.

The fix:

Problem itself manifests in horizontal scan circuit, somewhere between HOT and horizontal deflection coil connector, I'm almost certain that "scan capacitor" went bad due to heat in that area, look for capacitor that connects in series with horizontal deflection coil, it could be electrolytic or film type.

Good luck.

Thanks for all the in-depth feedback. At this time I plan on repairing the monitor if it ends up just needing a cap or other 1:1 off-the-shelf component(s) replaced. If the transformer is shot, PCB cracked, or some other advanced repair I will likely not mess with it and accept a $99 loss.

You know, if this problem only affects 2 modes, and other work just fine (especially the higher frequency ones) it might not be an electrical problem at all.
Modern CRT monitors and TVs are fully digital, all the parameters for different modes are stored on EEPROM memory and the chips insde use that to drive the CRT. It's possible the entries for these particular modes are glitched - not really that uncommon failure. That EEPROM can be a separate chip or on-die the main controller, but reprogramming it either way is difficult since you need to get a correct dump from the same model.
However because of subtle differences between CRTs, coils. flyback transfomers and other parts, there isn't one set of parameters that fits all monitors of the same type perfectly. There is usually a hidden menu for the manufacturer to adjust these on the production line - you should be able to correct this issue with that menu. It's like the OSD except more settings to change - just be careful about that because these usually allow values that might damage the monitor.
The only question is, can this menu be accessed without messing about the PCB inside - no idea. Google "service menu" and that monitor model and see what you can find.

retardware wrote:

Elektrotanya is your friend.

https://elektrotanya.com/gateway_ev700.pdf/download.html

Thank you very much for this golden find as I look into pursuing getting this thing repaired! 😎