Cornerstone ImageAccel MC1608C/11 and the IBM 6091-19 Monitor

Content by Helmut P. Einfalt, original HERE. Edited by Major Tom.

The MC1608C/11 is a 2 MB graphics card capable of driving fixed frequency monitors. It is no surprise that the Cornerstone monitors of the time (1993/4) are supported, but pretty surprisingly also the 6091 series by IBM.

I tested the card with a 6091-19. This monitor is based on a 20" Sony Trinitron tube and supports 60 (Mode 1 and 2) or 67 Hz (Mode 3) refresh rates at 1280x1024. The monitor has a built-in signal amplifier that allows attaching a second 6091-19 via the five BNC out plugs.

Originally, IBM created the 6091-19 to be driven by the ImageAdapter /A (and later the 6091-19i and the Image-I-Adapter, the latter offering more ISA standard refresh rates). Since there are no drivers for the IA/A and IA/I Adapters beyond Win311 and as yet no driver hack is known to make them work under Win9x, the 6091-19 (and the corresponding 19i) suffer from lack of capable graphics cards.

While there are several brands of ISA/PCI/AGP cards capable of delivering the necessary frequency ranges, the MCA community was restricted to the use of the ATI Mach32 or the Matrox MGA adapters, both of which are fairly rare and are said to call for some tweaking.

To my great surprise, Cornerstone's ImageAccel 1 series has native support for the 6091 series built in. Selecting the monitor is done via a set of jumpers in the JP1 position of the card (top right corner). Refer to the table below for the appropriate jumper settings.

Display Type JP1
1 2 3 4
Autosync on on on on
Cornerstone Color 19 1 off on off on
IBM 6091-16 and -19i on on off on
IBM 6091-19 on off on on
IBM 6091-23 on off off on
Cornerstone Color 20/70 2 off off on on
Cornerstone Color 21/76 3 off on on on
1 Not supported for ImageAccel 1280 controller
2 ImageAccel 1600/70 and 1600/76 controllers only
3 ImageAccel 1600/76 controller only

Installing the card is a pretty straightforward matter, in fact if you install it onto a working NT system, you'll be through the whole procedure in half an hour.

I've installed and tested the card in a 9595-ALF (486DX-2/50) with 64 MB of RAM, but other machines would do as well.

Hardware Installation

Step one: Before installing the card in the AVE slot (slot 7 -- the only one it will fit), download the ADF @80A6.ADF.

(or any other source; there is *no* ADF download at Cornerstone's).

Step two: Adjust the jumper settings at JP1 to match your 6091 monitor (see table above).

Step three: Provide a Base Video card for the ImageAccel in the BVE slot (slot 5). Since one of the readmes around states something about known problems with IBM's XGA and XGA/2 adapters I decided to plug in the short SVGA card that is of no use anyway...

Attach a monitor to the SVGA card, plug in the the ImageAccel (slot 7!) and attach the 6091-19 to the card. The 6091-19 should be set to mode 3 (i.e., to 67 Hz refresh).

(BTW, beware of any attempt to run the ImageAccel as standalone-card. Although I found some documentation somewhere saying that it *can* provide base VGA, this would require an option disk that no one has ever seen. The best I could get the card to do was to fill the 6091 screen with a nice huge red square -- optically pretty, but of somewhat limited use for configuring the machine...)

Step four: Fire up the engine. When the 165 error comes up, run automatic configuration, feed in the ADF(s) for the video card(s), reboot and -- presto: you'll have the nice surprise of seeing the following message at bootup on *both* the screens attached:

Settings for the ImageAccel Display:

Primary or Secondary Adapter <Primary><Secondary>

I/O base address: <2000><2010><4000><4010>

Memory base segment address: <0C0000><0CA000><0CC000><0CE000>

Interrupt Selection: <IRQ3><IRQ5><IRQ10><IRQ11>

The settings are not critical as long as they don't conflict with other settings. For the IRQ I chose 5, but that depends on the rest of the machine's setup. If you select the standard of <Primary> for the video adapter, you'll see all DOS based messages on the 6091. <Secondary> means that you use the ImageAccel only for HiRes output (which would require another monitor attached permanently to the BVA).

If everything is ok, the next boot brings up the following screen message on

"ImageAccel MC1608C/11" plus a long serial number, and

"MEM: C000, I/O: 2000, 6091-19"

Software Installation

Unless you've already a running installation, install WinNT 4.0 (workstation in my case).

Keeping the control monitor attached to the BVA during installation is a good idea:

There are two weird things you might notice:

(1) The DOS (text) based screen does *not* fill the whole of the 6091's surface, and,

(2) once you've got past the basic DOS/text-based installation sequence of NT, i.e., when NT pulls up the blue graphic background, you'll see everything blue in RED. My IBM 15X monitor that was attached to the SVGA did behave properly.

Cure: none for (1), and swap the R and B BNC plugs at the monitor for (2).

Once NT is up and running **in 16-color VGA mode** (standard driver for vga-compatible graphics card), it is time to feed it the ImageAccel NT 4.0 drivers.

You'll find them here or at the Cornerstone site.

Take the ImageAccel 1 NT 4.0 drivers and download **** to your HD.

Make a directory called NT40 and extract the files into that one. Format a 1.44 floppy and *copy the whole directory* onto it. The reason for this move is that the unzipped driver directory contains only 1.2 MB of data, but some 140 files, and that you can't get into a floppy's root directory. (Don't kick me for this statement of the obvious -- it took me over an hour and a couple of formats and re-formats of at least three floppies on three different machines before I found out why the heck 1.2 MB won't fit on 1.44 MB of free space -- neither NT nor Win95 are very helpful with their error messages in this respect...)

The next step is easy -- easier than reading the following instructions that I copied from the IA readme:

"If the ImageAccel Windows NT 4.0 display driver is being installed for the first time, you must first start Windows NT in VGA (640x480) mode before proceeding. If an update installation without a display/adapter configuration change is being performed, it is not necessary to revert back to VGA before installing the display driver. If the display/adapter configuration is changing and an update installation is being performed, we recommend that you first uninstall the existing ImageAccel display driver before proceeding.


1. Right click on the desktop and pick "Properties" to bring up the Display Properties window. Choose the "Settings" tab.

2. Select the "Display Type" button. A display type dialog box will appear. Select the "Change..." button in the "Adapter Type" section of the box.

3. A "Change Display" dialog box will open. Select the "Have Disk..." button. A box will appear indicating the drive where the Manufacturer's information is located. Select "OK" or change to the drive letter and path where the ImageAccel NT release resides.

4. A list of ImageAccel displays picks will appear. Select the appropriate controller with display or timing and press the "OK" button. The system will inform you that it will be changing its configuration. Click "Yes".

5. The operating system will inform you the display settings have been changed and that for the changes to take effect, Windows NT should be restarted. You can restart the system at that time or later, depending on your needs.

NOTE: Selecting an inappropriate display type may distort the screen or bring up the VGA display driver instead. If this occurs, simply reinstall the correct display if the display can be read, otherwise, select the VGA display from the boot menu upon powering up the system.

6. Restart Windows NT.

NOTE: After restarting Windows NT, a Windows NT "Invalid Display Settings" dialog box will appear with the following information: "A new graphics driver has been installed. The old default display resolution has been temporarily used by the system. Use the display option in the Windows NT Control Panel to select your preferred Display Resolution." This message is a misleading message generated by the operating system. Select OK to ignore the message and continue.

7.Choose your desired settings through the Windows NT Display Properties "Settings" and "ImageAccel" Pages. Some changes to the Control Panel default settings require you to restart Windows before the changes take effect.

NOTE: (...) Network NT Installation is not supported. "

While the machine is re-starting after step 7, you'll notice that the screen goes back to normal again, or, if you *did* swap the R for the B BNC-plug, it will come up with a **red** startup screen. Simply change the plugs again, and there you are... From now on, the second monitor attached to the SVGA will stop displaying as soon as the blue start screen comes up -- but then -- who needs a lowly 15-incher if he can have the 6091-19 ?

One more funny thing: the ImageAccel driver provides cursor color settings -- don't be scared if you cursor comes up in a bright yellow -- there is nothing wrong with it. Just change the settings in the Display Properties > ImageAccel menu (and reboot once more...).

And there we are: As far as the ImageAccel is concerned, installation is as easy as anything. And you end up with a wonderful combo of a working NT on a 9595 and a nice huuge display.

Now, if Cornerstone *just* could make an upgrade kit to 4 MB (and true color....)

Thanks to Ulrich Trunk for donating the card that revived the 6091-19.

Content created and/or collected by:
Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

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