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inakito
February 26th, 2014, 05:19 PM
Hi.
I am interested in purchasing a VT525 terminal. This terminal has no monitor. You connect it to an external monitor using a VGA connector.
Although i do not have tried it myself i have read on several places on the internet that this terminal does not work well with LCD monitors. In particular there is a claim that 132 columns cannot be used with other than CRT monitors. Some people complain about quality even when using 80 columns.

Does anyone have been able to use an LCD monitor with VT525 terminal, with acceptable quality?

Inakito.

NeXT
February 26th, 2014, 06:25 PM
I can find at least one photo where it's working with a cheap Dell panel so for the basic modes you should be fine. I assume for 132 column the panel needs to support an oddball resolution.

gslick
February 26th, 2014, 06:55 PM
The manual says this:


Monitor Requirements
The VT525 requires a multisync monitor that supports VGA 72Hz (37.8KHz horizontal scan rate), with a 15-pin, D-Sub connector. Typically most monitors today meet these requirements.

I tried using a VT525 with at least one LCD monitor where the display quality was not very usable. I'll have to hook one up again to the various LCD monitors I have around now and see how it looks.

-Glen

gslick
February 27th, 2014, 06:20 PM
I just tried three different LCD monitors that I had on hand with my VT525, a ViewSonic VP2000s, a Samsung 931B, and a Dell 1704FPTT. All three LCD monitors had the same issue with the VT525, the width of the vertical lines on characters varied from character to character across the display lines. Attempting to tune the display settings on the monitor just moved the issue from some characters to others characters across display lines. The display quality was bad enough that I would not use the VT525 with any of the LCD monitors I had on hand to try.

In contrast, I tried a ViewSonic GS790 CRT display and the display was perfectly acceptable to me with the VT525.

Unless someone tells you that they have seen in person a particular model of an LCD display with sharp and consistent characters across the display lines with a VT525 and you can find the same LCD display, I would assume that you would find the display quality with a random LCD monitor attached to a VT525 to be poor enough that you would rather not use it.

gslick
February 27th, 2014, 07:22 PM
OK, I tried one more LCD monitor that I had on hand, this time a ViewSonic VP150. I got reasonably acceptable results with this monitor. Maybe because its native resolution of 1024x768 is closer to the resolution of the VT525 than the other higher native resolution monitor I tried and the scaling works better.

This image was taken of the ViewSonic VP150 with the VT525 configured in 80x50 display mode. It looks slightly better in person. I didn't spend any time trying to capture a better image.
17510

Unknown_K
February 27th, 2014, 07:24 PM
I only used a CRT with my VT525's , you can do 132 column with those type of monitors.

NeXT
February 27th, 2014, 07:47 PM
LCD's have always been bad at handling nonstandard resolutions and refresh rates that almost any multisync CRT could handle.

inakito
February 28th, 2014, 11:40 AM
Thanks gslick for the test, that picture looks great!
By any chance did you try 132 columns on the same monitor?

gslick
February 28th, 2014, 02:53 PM
Here are three images of the VT525 with the ViewSonic VP150 at 25x80, 50x80, and 50x132.

Going from 25 rows to 50 rows doesn't change the quality as much as going from 80 columns to 132 columns does.

-Glen

175161751717518

inakito
February 28th, 2014, 03:12 PM
Wow, it is not that bad! It is a very usable 132 mode.
I would say that monitor does a very good work!

Glen, have you tried to change 'horizontal position' setting on this monitor? Does it improve/worsen anything ?

Thanks for the pictures!

gslick
February 28th, 2014, 03:45 PM
The adjustments on the VP150 are fairly limited in what they do, and they do not change the image quality all that much with the VT525. I used the auto tune feature and then tweaked the settings slightly, mainly just to center the image slightly better.

inakito
March 11th, 2014, 01:46 PM
well, i finaly bought the VT525. have tried with a couple of LCD monitors. Quality is aceptable on 80 col. mode but is awful in 132 column mode. gslick, your Viewsonic monitor does a far better job than my two monitors. it is interesting that the monitor with larger resolution gives poorer results than the cheap LG 15 inches. So far your Viewsonic is the winner and by a large gap. would like to see a hires picture of vt525 in 132 column mode over a crt monitor but i do not have one available.

inakito
March 12th, 2014, 03:28 AM
Have found that if you leave the monitor to detect automatically the video input settings, both monitors claim input resolution is 640x480. Which is strange, as math does not fit with 640: 132 columns x 6 pixels per column: 792 pixels. That would fit on a 800x600 display.
The VT520 monitor for instance has a resolution of 800x480 pixels (and yes, it is a rare resolution for a PC monitor).
I would like to add that in one of the monitors I have tested, I am able to set CLOCK and PHASE parameters. These settings improve a little the quality, but not too much.