[comp.sys.ibm.pc.hardware] VGA via DB25 into Mitsubishi AUM-1371A monitor?

dick@cimcor.mn.org (Dick Schlotfeldt) (10/12/90)

Can I use a VGA card to drive a Mitsubishi AUM-1371A? If so,
how should I wire the cable?

This color monitor has a D-sub 25 pin analog input connector
described below. It also has a nine pin TTL input and a BNC
composite video input. I want to connect a VGA card to the 25
pin analog input:

Pin                         Note
Number Signal               Number  Remarks
===============================================================
1      Sync GND
2      Red video             1
3      Red video GND         1
4      Green video           1
5      Green video GND       1
6      Superimpose control   2
7      Superimpose GND       2
8      Video input select           Low or open: BNC input video,
                                    High: Pin 9 composite video
9      Composite video in    3
10     Composite video GND   3
11     Composite video out   3
12     Composite video GND   3
13     PGA mode control      4      Low:400 lines, High:480 lines
14     Blue video            1
15     Blue video GND        1
16     Horizontal sync              TTL level
17     Vertical sync                TTL level
18     TTL color select             Low:16 color, high or open: depends
                                    on EGA card
19     NC
20     NC
21     INT                   5      (+5V)
22     Composite/RGB select  6      Low:RGB, High or open: composite
23     Analog/TTL select     6      Low:TTL, High or open: Analog
24     Remote                6      Low: mode switch is invalid
25     GND (shield)

Notes: 1.  0.6 Volts p-p, 75 ohms Positive
       2.  Low: 0 to 0.4 Volts, High: 1 to 3 volts, 75 ohms.
           Superimpose control provides high speed switching between
           composite video and RGB analog.
       3.  1.0 Volts p-p, 75 ohms, Sync. negative
       4.  The manual mentions the IBM PC/AT PGA board as
           an example source of the analog signal but I know nothing
           about PGA. I want VGA.
       5.  What does INT mean?
       6.  It is clear from the manual that I can leave these open and
           select analog input from a switch on the back of the monitor.

Some specs on this monitor:
  Horizontal sync 15.6 KHz to 35 MHz (automatically)
  Vertical sync 45 Hz to 75 Hz (automatically)
  Video bandwidth: 30 MHz
  Trio dot pitch: 0.31mm 
  Resolution: 800 dots horizontal, 560 lines vertical.
  Misconvergence: less than 0.4mm at center.
  CRT: 13 inch viewable, Diamond Matte coating, Super high contrast glass.

For reference, the Orchid Prodesigner VGA/Plus has this pinout:
1  Red                   9  Key
2  Green                 10 Sync return
3  Blue                  11 Monitor ID bit 0
4  Monitor ID bit 2      12 Monitor ID bit 1
5  TTL ground            13 Horizontal sync
6  Red return            14 Vertical sync
7  Green return          15 Not used
8  Blue return

Also, do you have any idea what sort of performance I can expect?
Will analog VGA provide a better picture than TTL input of EGA?
Can it handle 800 x 600 or is 640 x 480 the max? Is it likely to be
damaged if I try a resolution higher than it can handle?
I am currently using this monitor's RGB TTL input for EGA.

Thanks much for any help.
Dick Schlotfeldt       dick@cimcor.mn.org
St. Paul, MN