any, and I mean ANY VGA monitor will support EGA resolution - it was (is)
part of the spec - there is an adapter available so you can connect a 15 pin
cable to the 9 pin ega/cga monitor output, and the wiring for the adapter is
available on line.
As far as I know, the original XT did not support EGA, the choice was either
a CGA card that had a 9 pin and composite video with a resolution that was
really pathetic (640×200), ega went a bit higher (640×350 ) and VGA higher
still (64-X480).
wikipedia provides the pinouts
http://en.wikipedia.org/wiki/Enhanced_Graphics_Adapter
The other choice on XT machines was the monochrome (MDA) monitor which was a
much more useful monitor and much higher resolution - it also used a 9 pin
connector, pinouts below - note that the MDA display was frequently
destroyed by connecting it to a CGA card - but the repair is easy, replace a
$3 horizontal drive transistor - I fixed many.
http://en.wikipedia.org/wiki/IBM_Mon...isplay_Adapter
Now, what display is it that you need?
"Ignoramus16651" wrote in message
...
On 2010-04-08, Jon Elson wrote:
Ignoramus16651 wrote:
On 2010-04-08, Bill Noble wrote:
what kind of monitor? why is it hard to just fix it?
It is some kind of old EGA monitor, like those found on "IBM PC XT".
Yeah, our old Bridgeport/Romi lathe with EZ-Trak control has an ANCIENT
B&W EGA display with 9-pin plug. When it went out, I took it over to my
bench and found some solder joints in the HV/horiz. sweep circuit had
partially melted and fatigued, and resoldered them. To my surprise, the
monitor came back to life and is still working after quite a few years.
If you troll the consumer electronic junk swap meets you may be able to
find a compatible monitor. Some of the older NEC multi-sync monitors
will go down to EGA sweep rates. You ought to put a scope on the H and
V sync pins and find out what the actual H sweep rate is, then you can
look for a monitor that will work.
My old PC book says the EGA sweep rates were 15.75 - 21.85 KHz, MCGA was
31.5 and the original VGA was also 31.5 KHz.
I do not think that monitors have the sweep rate info on them
anywhere.
i