NSI Melange Video Port Issue

707lineman

Member
I just picked up a used Melange controller. I got it for a screaming deal on ebay. The one I learned on 18+ years ago had a DB15 jack for the video output on the monitor. However this one has a DB9 connector for the video. The console beeps when turned on and the submaster buttons light when bumped so I know its working. Has anyone ever used a console that had the DB9 jack? I tried a DB9 to DB15 for VGA but I don't think there was any converting going on so I got no video on my VGA monitor. Monochrome monitors are running around 100 on ebay which is what I got the dang console for HAHA
 
You need what is known as a TTL monitor, also known as an MDA monitor. These were indeed monochrome but you could also have a composite video monochrome monitor which will not work in this application.
MDA was before VGA, EGA, and CGA, so back a ways in technology. The prices for these monitors are usually pretty outrageous on Ebay, but sometimes you can come up with one for a good price. One place I have bought a brand new TTL monitor is: http://www.computerreset.com/monitors.html#6. Definitely call to see if they can still get them. I have the Miracle M107T amber on black screen from them and it works great with all the old DB-9 memory consoles like the Melange and GAM Access.
A TTL/MDA to VGA converter box is listed here: http://www.ebay.com/itm/XVGA-box-MD...250695?hash=item27de9858c7:g:oWsAAOxyNepRm8dX
but their DB-9 pinout does not correspond to the pinout I have for TTL/MDA. I am going to order one and see if it will work with my DB-9 consoles as it would be nice to use a flat-panel VGA monitor rather than the bulky TTL/MDA CRT unit.

Maybe more than you wanted to know. Good luck.
 
You need what is known as a TTL monitor, also known as an MDA monitor. These were indeed monochrome but you could also have a composite video monochrome monitor which will not work in this application.
MDA was before VGA, EGA, and CGA, so back a ways in technology. The prices for these monitors are usually pretty outrageous on Ebay, but sometimes you can come up with one for a good price. One place I have bought a brand new TTL monitor is: http://www.computerreset.com/monitors.html#6. Definitely call to see if they can still get them. I have the Miracle M107T amber on black screen from them and it works great with all the old DB-9 memory consoles like the Melange and GAM Access.
A TTL/MDA to VGA converter box is listed here: http://www.ebay.com/itm/XVGA-box-MD...250695?hash=item27de9858c7:g:oWsAAOxyNepRm8dX
but their DB-9 pinout does not correspond to the pinout I have for TTL/MDA. I am going to order one and see if it will work with my DB-9 consoles as it would be nice to use a flat-panel VGA monitor rather than the bulky TTL/MDA CRT unit.

Maybe more than you wanted to know. Good luck.
Thank you very much for enlightening me on this. Ill look around and see what I can find.
 
Please forgive the lengthly post, but I’m excited to have finally found time to test a GBS-8219 MDA/CGA/RGB to VGA converter box, which in theory would allow the use of a standard VGA monitor with many of the “old school” memory consoles with 9-pin video displays from the late 1980’s to the mid-1990’s such as the GAM Access, Rosco-ET Eclipse, NSI Melange, and ETC Vision and Microvision.
The converter cost $155 plus shipping and was obtained from:
http://www.ebay.com/itm/XVGA-box-MDA-RGB-CGA-EGA-to-VGA-industrial-video-Converter-/171238250695
They ship very promptly.
The instruction manual proved to be somewhat cryptic, so experimentation was necessary. Consoles I tested the unit with were GAM Access and NSI Melange which output a MDA signal, and an ETC Microvsion FX which outputs a CGA-type signal.
First up was trying to get a display on the VGA monitor from an NSI Melange MDA output.
A cable with a molded DB-9 male on one end and bare wire on the other was supplied with the converter. A loose DB-9 male and female were also supplied, but without hoods. If you still have a RadioShack, the hood is stock number 276-1513.
Difficulty getting the MDA to work was encountered with the supplied cable because pins 6 and 7 were tied together inside the molded DB-9 end, which meant that the pin 6 Intensity and pin 7 Video signals were shorted to each other producing an unusable display. Twisting off pin 6 fixed that problem.
The converter itself has an on-screen menu which customizes the unit. Looking at the attached photos, the important choices are RGB (A) format, separate H &V sync, 75 ohm impedance, and progressive scanning. In theory pin 7 should carry the video signal, but the converter manual indicated that pins 6 and 7 were not hooked up inside the converter. By playing with different combinations of connecting the molded plug’s pin 7 Video wire to pin 3 (Red), pin 4 (Green), and pin 5 (Blue) of the male DB-9 you’re putting on the bare end, you can create the color text you desire on a black background. I tied the pin 7 wire to pin 4 (Green) for the classic “green screen” look. See the MDA cable wiring diagram for details.
The same cable worked fine using a GAM Access console.
The resulting display is sharp and very usable, but not perfect. Some of the text has slight imperfections, and there is a little what I would call “jittering” or slight pulsing of certain graphics lines. You can see some of this in the photos. But hey, for a reasonable price I’ve got a nice lightweight flat panel monitor for my 25-year old memory consoles!
Getting a display on the VGA monitor from an ETC Microvision FX’s CGA-type output was pretty straight forward and the results were similar. See the CGA cable wiring diagram for the details. Have fun!
MelangeScreen.JPG XVGAmenu.JPG MelangeXVGA.JPG MicrovisionFXscreen.JPG MDAcable.jpg CGAcable.jpg
 

Users who are viewing this thread

Back