17. What is this article about?
1. This is a set of step-by-step tips for how to install a new AGP or PCI video card when the PC has (non-card) video capability integrated (built-in) on the motherboard, and there is apparently no jumper, switch or BIOS setting to disable that built-in video.

This article is based on my personal experience with an Intel TC430HX "Tucson" motherboard installed in a relative's Toshiba Infinia 7161 PC. We replaced the on-board 2MB S3 Virge DX video with an 8 MB Matrox Millennium PCI card.

This information probably applies to other PC brands and models also based on this motherboard (MB), such as some HP Pavilions. It may apply to similar OEM and retail Intel MBs with on-board video. It may not apply to non-Intel boards.

Note:

These instructions don't apply in all cases.

Note:

In some cases, it is apparently impossible to defeat the built-in video.

If your PC has a motherboard like the Tucson I fought with in 1998, the on-board video may be silently auto-disabled if you take precisely the correct, undocumented, steps.

Before taking those steps, however, you need to do your due diligence on finding a switch, jumper or BIOS config setting to disable the video.

• BIOS Technical Reference Manual (TRM)
• Motherboard TRM
• Hardware Service Manual
• FAQs on the topic

Also try their service parts pages and see if manuals can be ordered. As far as I know, no TRMs or Service Manuals are available for HP Pavilions (unlike HP Brios, Vectras and Kayaks), either on-line or in paper form.

Inspect the motherboard and see if you can figure out who actually made it, and what model/part/SKU it is. It is often impossible to tell by visual inspection, particularly on the truly no-name boards made by firms like Jabil. Ask in the PC maker-related, and PC component netnews discussion groups, such as comp.sys.ibm.pc.hardware.chips

Then go to the MB manufacturer's web site and see what tech ref info you can dig up.

In my case, the MB turned out to be an Intel OEM board, and that was key to getting the info on how to nuke the video. After determining the manufacturer and model, I was able to go back to the component newsgroups (esp. comp.sys.intel) and ask the question again, and actually got a response from an Intel person, who explained the magic sequence.

And yes, I did hit the Intel web site, and downloaded every page and Acrobat document available on the TC board - nothing discussed video disable. Getting a solution involved a large measure of luck. Be sure to keep some handy.

The Sequence

If indeed your PC has no switch, jumper or BIOS setting for disabling the on-board video, then this is probably the proceedure for installing a replacement video card.

This is for Windows 95 OSR2 (OEM Service Release 2, also known as Windows 95B). Generic Win95 and Win98/ME is similar. NT has some differences. Caution: This is from memory. Perform this at your own risk. Your mileage may vary. CMOS batteries not included.

1. Can you actually use the new card?
   • Do you have a spare PCI or AGP slot for the new card? Most PCs have ample PCI slots, but AGP is a slot, and not a bus. If the on-board video is AGP, you may well not have an AGP slot for an AGP card.
     
     If you have a spare PCI slot, but no spare AGP slot, you might be able to use a PCI graphics card, but keep in mind that the latest-generation of super raster-blasting graphics cards are offered almost exclusively in AGP, and rarely PCI anymore. You may need to do some digging to find a decent PCI card.
     
     
   • Do you have a spare bulkhead opening for the new card? (Some openings are shared between an ISA and a PCI slot, since these standards have the actual card on opposite sides of their bulkhead plate. You could have a free slot, but no free opening.)
     
     
   It theoretically isn't necessary to worry about an IRQ for the new card, as it will likely be assigned the IRQ that the built-in video used. However, if the old card refuses to die, having a spare IRQ can reduce the complications of resolving matters.
   
   
2. Collect some data on the current drivers.
   
   Select: Start:Settings:ControlPanel:System:DeviceManager:
   [+] Display Adaptors
       [Icon] RasterBlaster 3Dfx Plus (name of built-in video)
   [Properties]
     [Driver]
       [Driver File Details]
   Make a note of the paths and names, especially those that appear to be supplied by or for that particular chipset, like "3DFX64.VXD".
   
   Also get into
   ...:DeviceManager:Computer
   [Properties]
     (*) Interrupt request (IRQ)
   and see if you have any spare IRQs (they will be assigned to "IRQ Holder for PCI Steering" but will have no device currently also assigned to that IRQ).
   
   If you don't have any free, you might want to consider making one available, if only temporarily, so that there at least won't be any IRQ conflicts if Win9x attempts to configure both old and new video. If you aren't using both COM ports, or the LPT port, you can usually free the IRQ by disabling the port in BIOS setup (and it wouldn't hurt to "remove" it in DeviceManger just before rebooting to BIOS). If no ports are spare, you might temporarily "remove" any modem card in DeviceManager and from the slot.
   
   
3. Install drivers for new card?
   If the vendor of the new card instructs you to install the software before installing the card, do so now, but don't install the card, and don't reboot.
   
   
4. Because you are probably changing video chip brands, and almost certainly changing drivers, drop back to generic VGA resolution (which works with both your old built-in video and your new card - we actually switch to the VGA driver at step 6).
   
   Place the mouse sprite somewhere on the desktop wallpaper (i.e. not on an icon or toolbar), and right-click.
   Select: Properties
   Configure this screen for:
      640x480 display area or resolution,
      256 (8-bit) color,
      small fonts,
      60 Hz refresh rate
   [Apply][OK]
   or whatever, however, you don't need to reboot at this time, although you can if you wish, but follow the no-reboot cautions later.
   
   
5. Remove the old video controller in DeviceManager.
   Start:Settings:ControlPanel:System:DeviceManager
   [+] Display adaptors (to show the current video)
   Select the line for the built-in video.
       [Icon] RasterBlaster 3Dfx Plus (name of built-in video)
   Select [Remove], then [OK]
   
   DO NOT REBOOT at this time, or Plug'n'Play will rediscover your same old built-in video.
   
   If the first pass through these instructions doesn't work, try it again, and instead of [Remove], select
   [Properties] [General]
   [x] Disable in this hardware profile
   [_] Exists in all hardware profiles
   
   
6. Switch to the standard VGA driver:
   Start:Settings:ControlPanel:AddNewHardware
   Search? (*) No [Next]
   Select "Display adapters" [Next]
   Select: (Standard display types)
      Standard Display Adaptor (VGA)
   [Next]
   (and I didn't go beyond this point when I wrote this)
   
   
7. Shut down the PC (DO NOT REBOOT)
   
   
8. Unplug the PC.
   
   Yes, really unplug it. Most recent PCs (with APM) are never really "off". Their power supplies provide at least +5Vdc to the AGP and PCI slots whenever they are plugged in. Swapping I/O cards without actually unplugging can result in serious hardware damage.
   
   
9. Install the new video card.
   Be sure to reconnect the monitor from the old port to the new card.
   
   
10. Power up the PC.
    The BIOS will discover the new card and give it preference over the on-board video. Because the old video is "removed" by Win9x, Win9x won't try to use the old on-board video, and will configure the generic VGA driver (or if you're lucky, the card's own driver) to the new card. Your desktop will probably be a scrunched mess, however.
    
    
11. Remove the basic VGA driver in DeviceManager.
    You may need to use the FlagLogo key to pop the Start menu.
    Start:Settings:ControlPanel:System:DeviceManager
    [+] Display adaptors (to show the current video)
        [Icon] Standard Display Adaptor (VGA)
    Select the line for the VGA.
    Select [Remove], then [OK]
    DO NOT REBOOT.
    
    
12. If you weren't instructed to install the software for the new card before installing the card, install the software for the new card, either using the vendor's instructions, or
    Start:Settings:ControlPanel:AddNewHardware
    as at step 3.
    
    
13. Reboot.
    You "should" now be running on the new card with the correct drivers. Right-click the desktop to configure the optimum res/color/depth/refresh/etc for the card's video RAM and the monitor's capabilities.
    
    
14. Old Chipset Still Configured?
    Try it again, except this time, as the last task in Step 5, rename all the old-chipset-specific files from
    Whatever.VXD
    to
    Whatever.VXD.old,
    so that Win9x can't find and configure them.

Why do motherboard makers use "silent disable"?
Because with a BIOS disable option, you could leave yourself unable to re-enable the on-board video (for example, if the new video card is defective).

So why not use a switch or jumper?
Because most customers hate them, and they add a few cents to the factory cost, the majority of PC customers never upgrade their video, and there are static discharge risks when customers touch MBs, but the real question is...

Why don't the PC makers document the silent-auto-disable, or at least put the above procedure on their web sites?

Why indeed. The above procedure is admittedly complicated, and a nuisance, but a significant non-zero percentage of the PC population do purchase video upgrades (which is a thriving after-market business), so this process is undertaken thousands of times.

If the PC makers won't document it, why don't the video card makers do it?

Again, Why indeed.
It is more likely their support phone that rings when the customer can't get the spiffy new AGP card to work.

Anyhow, welcome to Plug&Pray.
If you are beginning to think you will have different criteria when you buy your next PC, this is called enlightenment, grasshopper.