Running an old computer with a new monitor

[meirman]

Is there an adapter that will allow me to connect a new monitor, with
a 15-pin connector, to a laptop computer that has a 9-pin output jack?

(I have an adaptor to do the opposite, use a 9-pin monitor with a 15
pin video card)

Thanks.

Meirman

 

[rjn]

Is there an adapter that will allow me to connect a
new monitor, with a 15-pin connector, to a laptop
computer that has a 9-pin output jack?

No snap answer is possible, as it depends on what
video signal standard that old port was intended
to drive.

If it's a common historical PC digital video signal
(MDA, CGA, MCGA, EGA, PGA, 8514/A), the answer is NO.
(and no, these can't be adapted to DVI-D either)

If it's some proprietary video signal, it may also
be a lost cause.

If it's an analog signal (VGA, XGA, SVGA or later),
then a simple adaptor may be possible.

 

[Tal Fuchs]

What computer has a 9 pin output jack for video ?
Are you sure it's not the COM port ?

Tal

 

[J. Clarke]

In comp.sys.ibm.pc.hardware.video on Wed, 20 Apr 2005 16:07:45 +0200


Ooooo. That's a good point. Well, below I realize that I am sure it
is the video port.

The 15 pin high density connector came in with VGA. Prior to that the IBM
PC family had a 9-pin connector the same size as the 15-pin.

It's a Bromwell B300 laptop. Looking for specs, etc, I found one for
sale on Ebay and one on an auction site like Ebay, and the ad said
that it ran Windows 3.0.

The LCD? screen just shows some horizontal lines at start-up, and then
goes blank. So I plugged in an old monitor of mine.

Now, I'm using iirc an EGA (or maybe VGA or CGA-?) monitor with a
9-pin plug connected to the 9-pin jack, and I can see it start booting
by the lights: the floppy drive lights up, the hard drive lights up,
and then some "text" appears on the monitor.

It's illegible. It's about 1 1/3 lines long, even though I'm sure
it's really less than a line. My monitor worked fine a few years ago
when it was connected to an AT computer, but now if I adjust the
vertical hold, I can get it stable but only with 3 copies of the same
text, one above the other.

Another line or two of "text" appears as the probable booting
continues. All of the "text" is in 3, maybe 4 colors, blue, red,
white, and maybe light green. The letters are block-shaped.


This is the immediate problem. My previous question was a general one
-- Do I have to keep a CGA or VGA monitor around for testing old
computers? -- and it relates to a specific question that applies here
-- maybe I should test this computer with a SVGA monitor? Of course
I have one of those, but they have 15-pin plugs.

First, the machine you have if it has 9-pin video does not have any kind of
VGA. It could have EGA, CGA, or something proprietary. The symptoms
you're describing are the classic ones of a mismatch in timing between the
monitor and the display adapter. It may be that your monitor is
fixed-frequency (either single or with several to choose from) and
incapable of synchronizing with the display adapter in the computer or it
may be that the monitor's synchronization mechanism has failed. Or of
course it may be that the display adapter is fried.

Now as for keeping a monitor on hand for dealing with old computers, yes, a
good digital (in the sense of the CGA/EGA era, not a modern DVI monitor)
autosynchronous monitor would be a very good thing to have if you routinely
deal with _very_ old computers. The trouble is finding a good one that
still works. My favorite was a Roland model the number of which escapes
me--it locked onto everything I ever tried to throw at it. But it also
died long ago and I don't see any on ebay.

I don't think any current monitors can handle the old digital
signalling--when VGA was new most autosynchronous monitors that handled VGA
could but that was a long time ago.

 

[meirman]

In comp.sys.ibm.pc.hardware.video on 19 Apr 2005 15:49:21 -0700 "rjn"

No snap answer is possible, as it depends on what
video signal standard that old port was intended
to drive.

If it's a common historical PC digital video signal
(MDA, CGA, MCGA, EGA, PGA, 8514/A), the answer is NO.
(and no, these can't be adapted to DVI-D either)

If it's some proprietary video signal, it may also
be a lost cause.

If it's an analog signal (VGA, XGA, SVGA or later),
then a simple adaptor may be possible.

Well, I'm not sure what it is.

This was a general question and I also had a particular computer in
mind, a Bromwell B300 that a friend asked me to help him with.

He doesn't expect it to work again. He just wants to get his personal
data off of it. I haven't found out much about the computer except
that it ran or could run Windows 3.0.

I put more details in my reply to Tal's reply, next.

Thanks.

Meirman

 

[meirman]

In comp.sys.ibm.pc.hardware.video on Wed, 20 Apr 2005 16:07:45 +0200

What computer has a 9 pin output jack for video ?
Are you sure it's not the COM port ?

Ooooo. That's a good point. Well, below I realize that I am sure it
is the video port.

It's a Bromwell B300 laptop. Looking for specs, etc, I found one for
sale on Ebay and one on an auction site like Ebay, and the ad said
that it ran Windows 3.0.

The LCD? screen just shows some horizontal lines at start-up, and then
goes blank. So I plugged in an old monitor of mine.

Now, I'm using iirc an EGA (or maybe VGA or CGA-?) monitor with a
9-pin plug connected to the 9-pin jack, and I can see it start booting
by the lights: the floppy drive lights up, the hard drive lights up,
and then some "text" appears on the monitor.

It's illegible. It's about 1 1/3 lines long, even though I'm sure
it's really less than a line. My monitor worked fine a few years ago
when it was connected to an AT computer, but now if I adjust the
vertical hold, I can get it stable but only with 3 copies of the same
text, one above the other.

Another line or two of "text" appears as the probable booting
continues. All of the "text" is in 3, maybe 4 colors, blue, red,
white, and maybe light green. The letters are block-shaped.


This is the immediate problem. My previous question was a general one
-- Do I have to keep a CGA or VGA monitor around for testing old
computers? -- and it relates to a specific question that applies here
-- maybe I should test this computer with a SVGA monitor? Of course
I have one of those, but they have 15-pin plugs.

Tal

Is there an adapter that will allow me to connect a new monitor, with
a 15-pin connector, to a laptop computer that has a 9-pin output jack?

(I have an adaptor to do the opposite, use a 9-pin monitor with a 15
pin video card)

Thanks.

Meirman

Meirman

 

[Tal Fuchs]

Why not getting out the HDD to another machine and trashing forever this old
computer ?
I think you will have much more luck with this then trying to find an old
CGA monitor

Tal

 

[Not Gimpy Anymore]

The 15 pin high density connector came in with VGA. Prior to that the IBM
PC family had a 9-pin connector the same size as the 15-pin.


First, the machine you have if it has 9-pin video does not have any kind of
VGA. It could have EGA, CGA, or something proprietary. The symptoms
you're describing are the classic ones of a mismatch in timing between the
monitor and the display adapter. It may be that your monitor is
fixed-frequency (either single or with several to choose from) and
incapable of synchronizing with the display adapter in the computer or it
may be that the monitor's synchronization mechanism has failed. Or of
course it may be that the display adapter is fried.

Now as for keeping a monitor on hand for dealing with old computers, yes, a
good digital (in the sense of the CGA/EGA era, not a modern DVI monitor)
autosynchronous monitor would be a very good thing to have if you routinely
deal with _very_ old computers. The trouble is finding a good one that
still works. My favorite was a Roland model the number of which escapes
me--it locked onto everything I ever tried to throw at it. But it also
died long ago and I don't see any on ebay.

I don't think any current monitors can handle the old digital
signalling--when VGA was new most autosynchronous monitors that handled VGA
could but that was a long time ago.

Just to add what has already been correctly stated - the 9 pin will be
either CGA or EGA, and indeed just about every monitor supporting
VGA will not scan down to those frequencies.
CGA was 15.7 kHz, and I think EGA was 21 kHz.
I think there was even a MGA (Monochrome) but that stuff has really
faded from the ole noggin.

Perhaps some TV type of product can sync to the CGA, *if* that's
what the machine puts out, but you still have the challenge of mating
up the proper connection. Also, most TV products still want encoded
dolor, and C/E GA used RGB.

If you could find one of the old original NEC multi-sync monitors, it
should work - but how long will it live???

Looks pretty futile, overall, from this perspective.

 

[J. Clarke]

Just to add what has already been correctly stated - the 9 pin will be
either CGA or EGA, and indeed just about every monitor supporting
VGA will not scan down to those frequencies.
CGA was 15.7 kHz, and I think EGA was 21 kHz.
I think there was even a MGA (Monochrome) but that stuff has really
faded from the ole noggin.

Even if they did scan that low, prior to VGA the signalling used on the IBM
PC was digital, not analog--so the monitor would also have to be able to
handle that.

There was an IBM "Black and white" board (that was the actuall marking on
the board) commonly called the "Monochrome Display Adapter" although that
was never official IBM terminology that was text-only and a third part
graphic version from Hercules that went through a number of variations, and
in addition the EGA adapter could output to a monochrome monitor.

Perhaps some TV type of product can sync to the CGA, *if* that's
what the machine puts out, but you still have the challenge of mating
up the proper connection. Also, most TV products still want encoded
dolor, and C/E GA used RGB.

The "real" CGA had an composite output--to use a TV from the 9-pin connector
you'd need a transcoder.

If you could find one of the old original NEC multi-sync monitors, it
should work - but how long will it live???

The NECs tended to be short-lived in my experience--I'd be surprised if he
found one working. I went through a couple of them myself. I think it's
more likely that he'll find a working CGA, EGA, or IBM monochrome display
than a multisynch.