Archived from groups: comp.sys.ibm.pc.hardware.video (
More info?)
Not Gimpy Anymore wrote:
> "J. Clarke" <jclarke.usenet@snet.net.invalid> wrote in message
> news:d48ecf02un8@news2.newsguy.com...
>> meirman wrote:
>>
>> > In comp.sys.ibm.pc.hardware.video on Wed, 20 Apr 2005 16:07:45 +0200
>> > "Tal Fuchs" <fuchs_t@bezeqint.net> posted:
>> >
>> >>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.
>>
>> 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.
>>
>> >>Tal
>> >>
>> >>"meirman" <meirman@invalid.com> wrote in message
>> >>news:ikha615gjt22fk8j0aar0nnb5hj1b6svgp@4ax.com...
>> >>> 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
>> >>> --
>> >>> If emailing, please let me know whether
>> >>> or not you are posting the same letter.
>> >>> Change domain to erols.com, if necessary.
>> >>
>> >
>> >
>> > Meirman
>> > --
>> > If emailing, please let me know whether
>> > or not you are posting the same letter.
>> > Change domain to erols.com, if necessary.
>>
>> --
>> --John
>> to email, dial "usenet" and validate
>> (was jclarke at eye bee em dot net)
>
> 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.
> Looks pretty futile, overall, from this perspective.
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
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