..........the attachment is snips from a document that Roger
pointed me toward (which lead to a number of other links, also).
gregy
-- This mail was written by user of Arachne, the
Ultimate Internet Client
9517 Modification Techniques
----------------------------
==========================================D===============================
I will put my comments inside boxes like this to keep them
separate from the text I've cut from that report
==========================================D===============================
---------------snip----------
Monitors like the IBM 9517 are not fixed frequency but are XGA compatible.
This was an IBM abortion and not compatible with VGA/SVGA even for booting
your PC.
---------------snip----------
==========================================D===============================
What this means is that unless you have drivers installed in
your config.sys, or part of your BIOSes, you cannot see your
computer booting.....until Win9x or some other OS finally gets
loaded/booted and installs its drivers....see following:
==========================================D===============================
---------------snip----------
P.S. I see that the IBM 9517 can do 1024x768 if you can get to 85Hz
vertical interlaced, maybe starting with a 1240x768 interlaced mode and
fiddling the frequency up in a similar way that I did would work for the
original question? Of course interlaced modes are yucky unless you're
viewing images...
---------------snip----------
==========================================D===============================
The guy above did extensive tweaking and got possible results
which perhaps could be applied to the Video Card to drive the
9517.........
The guy below actually modified the internal electronic circuits
to make the 9517 work in a very good high resolution mode.
==========================================D===============================
---------------snip----------
Modifying an IBM 9517 XGA Monitor for SVGA Operation
(From Arnoud van der Wel ([EMAIL PROTECTED]).)
Well, I did this to two of them about a year ago. Of course I wrote down
what I did, so I'll try to reconstruct for you what I did.
There are two modifications, one is the H-FREQ control, the other is the H
SHIFT VGA control.
To boot, you need it to display the standard 31.5 kHz VGA text mode.
Turning the H FREQ pot (on the rear edge of the PCB) will eventually give
you a display, but it is off-screen to the right. You then adjust the H
SHIFT VGA pot (on the right of the PCB) and find that this pot has
insufficient range to center the display. The H FREQ pot is 4.7K from the
factory. It is in series with an 18K SMD resistor on the solder side of
the PCB. I found that I had to turn the 4.7K pot to max resistance to move
the display to the left, so I removed the 18K resistor and the 4.7K pot,
and replaced them with a 22K resistor and a 10K pot.
I was then able to center the display for text mode. The only problem is
that the horizontal linearity in text mode is now off. The letters near
the right of the screen are narrower than elsewhere. The problem is not
serious (a casual observer does not see it) so I can live with that.
Moreover, I never use text mode anyway (except during booting and for BIOS
setup, etc.) The 320*200 mode (games) also works correctly after this
modification.
Now, we want it to sync to highter refresh rates, specifically, 1024*768.
That is the mode I adjusted it for. All the 1024*768 parameters are
separately adjustable from the ones for the other modes, except the H
FREQ. The pots that govern this mode are all labeled "4,5", meaning, I
presume, that they govern the operation of what the monitor manufacturer
calls mode 4 and mode 5. I found these to coincide with H frequencies of
over approximately 50 kHz.
I found that by tweaking the H freq, I could get the text mode to be all
right, *or* the 1024 mode, but not both at the same time. (BTW, I run 1024
with a pixel clock of 77 MHz, H freq. of 57.63, and V freq. of 68.13 Hz. I
don't know what the specs for this monitor are, so I thought it was
prudent to stay on the low side.)
So I needed two instead of one H FREQ pots. I also found that there is a
relay click if you throw something over 50 kHz at this monitor. Hence, I
tapped the relay coil to give me the 0/12 volt signal to tell me what mode
the monitor is displaying. This signal I take to a little PCB that holds
my two H FREQ pots, an inverter, and two NPN transistors that switch in
one or the other pot instead of the original one.
The schematic is shown in ASCII below. Or, see the Gif version provided
by: Puiu Chiselita ([EMAIL PROTECTED]).
TO H-FREQ
o
|
+12 VDC +------+-----+
o | |
| / /
| \ 680 680 \
| / /
100K 1N4148 |/ E | |
RELAY o---+--/\/\--|\ 2.5K
| 100K \ / /
| / | |
| | |/ C C \| 1N4148 100K
| +----| NPN NPN |---+--|
Transistors can be any general purpose type:
* Typical NPN: 2N2222, 2N3904, BC547.
* Typical PNP: 2N2907, 2N3906, BC557.
I added the diodes to make sure we have a real OR circuit here, not a bit of
AND left in it, since that would (albeit momentarily) drive the H FREQ up way
too high and send the monitor into its OV protection.
Now I can tweak the H FREQ pot for both modes separately. To sum up, my 9517
now displays VGA text modes, 320*200, and 1024*768 in approx 70 Hz. When it
is warm, I can also get it to display 640*480. I could probably do a fix for
that too, but haven't bothered since I don't need that mode. Moreover, I
don'thave schematics, so I'm a bit hesitant to continue modifying it, when it
already works adequately for my use right now. The H linearity in the 320 and
1024 modes, by the way, exhibits no problems.
This solved monitor number one, and oddly enough, when I did monitor number
two. I was able to get it working after installing only mod number one. A
little help from the VGA card (Diamond Speedstar if I remember correctly) did
the rest. So maybe you are in luck and need only one mod. A flexible VGA card
definitely helps. (Or good setup-software for the VGA card.)
When you are turning all the little presets, be careful not to short the wipers
to the chassis... use a plastic tool! The wipers are not insulated from the
screwdriver slots. You can easily destroy some of the SMD transistors by doing
that. That's what I did, and I had some VERY lucky guesswork in unsoldering
them and replacing them by normal transistors (that is what I tend to do when
I find a dead SMD transistor...)
These are beautiful monitors and well worth modifying. Fortunately, not a lot
of people are able to do this, and this means that they are available rather
cheaply. :)
-------------snip-----------
==========================================D===================================
These are my comments from here to the end.....
These snips were taken from a much longer document which Roger gave
me the URL to.....now....they indicate possible good results, in DOS,
by using both the Software and the Hardware modification routes....
..in addition, it is possible that I will be able to track down those
drivers for the 9517 XGA...(if they were not just a figment of my
imagination).........
gregy
