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How much of the screen is used on IBM mono screen?

offensive_Jerk

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I have a mono screen, and the display does not use the full screen. There is maybe a inch and a half border around that does not display. Is that how the screen is suppossed to be?

If not can it be fixed?
 
Sorry,

Computer is IBM XT.
I have a MDA card, but it's small. I don't think official IBM brand when looking at the huge MDA cards on the internet.
It's hooked up to a IBM 5151 Monochrome monitor.
 
Sounds like the power supply output in the 5151 is sagging a bit. Not that uncommon, and usually due to failed capacitors.

It's possible to adjust for more width (VR402 and L503), but I'd check the PSU output first; when the PSU output goes low, the picture shrinks.

The voltage at the PSU output should be 15VDC. If it's low, change C603 (4700 uF, 35v) and C604/605 (4.7 uF, 50v). Also check R601 (1 ohm, 5w) and R602 (10 ohm, 2W).
 
You're talking about the IBM XT PSU where the monitor plugs in, correct?

EDIT: Nevermind I see you wrote IN the 5151.
 
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Did you just get this 5151? Was it shipped via the normal gorillas?

If so, one other thing to check is that the yoke on the CRT is fully forward (i.e. toward the faceplate, away from the socket) on the neck of the tube. If it slipped backward during shipping, it can also make for a too-small image.

But since you'll have it open anyway, check the PSU output. The 5151 is a very simple monitor as monitors go.
 
Sounds like the power supply output in the 5151 is sagging a bit. Not that uncommon, and usually due to failed capacitors.

I'd think that a sagging PSU would cause an uneven picture, like when you try to display too much bright color on a TV.

It's possible to adjust for more width (VR402 and L503), but I'd check the PSU output first; when the PSU output goes low, the picture shrinks.

I found a couple pictures on the net of 5151s running, and none of them had a picture that fills the entire screen. My 5151 doesn't either, so I'd assume that with the normal factory settings, you should get a border area like that.

Also, I'm sure we've all seen what happens when you try to run a CRT in damp conditions. The picture shrinks and becomes fuzzy because the moisture in the air sucks away voltage. I've even seen screens go completely blank when this happens.

Did you just get this 5151? Was it shipped via the normal gorillas?

Monitor shipping is always perilous, because CRTs and plasma displays have glass, and LCDs have a fragile membrane screen. I'm fortunate that I got my 5151 locally.

But since you'll have it open anyway, check the PSU output. The 5151 is a very simple monitor as monitors go.

Yes, you can't get much simpler than a TTL monochrome monitor.
 
Yes UPS shipped it.

I am wondering about this, because I have never seen a 5151 screen before and was not sure if this is normal.

Will crack her open and investigate.
 
Put some pictures up.

It seems a little like you have the brightness set way too high. I strongly suggest that you turn it low untill the background turns black, and the letters aren't "blooming" (they should be rather dark green, but still comfortable to read). If you run it too much with the brigthness too high, the risk of burn-in gets higher.

By the way, my 5151 uses just the same borders as yours, so I think it should be like that. It is not a graphics card, and it is only intended for text, so the outermost space is really there to simulate the margin of a typed paper.
 
It seems a little like you have the brightness set way too high. I strongly suggest that you turn it low untill the background turns black, and the letters aren't "blooming" (they should be rather dark green, but still comfortable to read). If you run it too much with the brigthness too high, the risk of burn-in gets higher.

By the way, my 5151 uses just the same borders as yours, so I think it should be like that. It is not a graphics card, and it is only intended for text, so the outermost space is really there to simulate the margin of a typed paper.

Yes, that was my thoughts too. Could it be the brightness is just set way too high?

Tez
 
All the 5151's I've seen have the same border, including my own and I've adjusted them as wide as practical, also needing to allow for the image shifting slightly to the right in the Hercules graphics mode, for what ever reason that is.
 

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Paul, if you turn up the brightness on your screen so the raster is visible, maybe the OP could get a better idea. To my eye, the image on yours appears to cover more of the screen than it does on AJ's monitor.

Maybe it's been too long since I've had a 5151 on my desk. I ditched the 5151 fairly early on and went to a 14" Taiwanese model and a 15" Mitsubishi fairly early on. To me, the 5151 felt like I was working in a cave.
 
I put the brightness and contrast to full, so you could see the fully displayable area.

I guess it is normal to have the border.
 
Okay, you guys are right. I got spoiled fairly early on. AJ's display is normal.

IBM was never one to consider human engineering--and that probably extends to putting a 10" image on a 12" CRT.

Compare the keyboard and display on a Displaywriter to, say, a Tandberg terminal of the same time (It was the German trade unions that made human-friendly hardware more financially attractive). My suspicion is that the reason that IBM lagged so far behind (what was the first monitor with a tilt-and-swivel base that they offered?) was that most of IBM's sales base was in the US, that was very slow to adopt any sort of workplace standards legislation.

To this day, I still use a couple of Acco ergonomic workstations for my computer work. I suspect they're worth more to someone today than the hardware stitting on them.
 
For what it's worth, my IBM 6318 SVGA monitor won't fill the whole screen no matter what you do. It can fill the whole width using the knobs on the front, but it won't fill the whole height (giving you kind of a fake, ugly stretched 16:9 widescreen effect)

And I think, though I may be wrong, that the first IBM swiveling monitor was the original PS/2 monitor.
 
IBM was never one to consider human engineering--and that probably extends to putting a 10" image on a 12" CRT.

It's not just the 5151. My Tandy CM-11 has a huge border as well. On the other hand, I've used two different TVs with the CGA composite output on my 5150, and on both the border is much smaller and gets partially cut off around the corners of the screen.
 
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