Display Adapter Failed – Using Alternate
Explanation: Although rarely seen today, some early system systems have the ability to support a primary and a secondary video display (the secondary typically being monochrome text) and the ability to switch to a backup (for lack of a better term) in the event of a failure. This was very popular with governmental users. The essence of the error is that the system has detected a failure in the primary display and therefore is using the secondary one. Some system that have both an AGP and PCI video card can detect a problem and switch to the other. Some dual-PCI configurations can do this as well.
Diagnosis: The BIOS setting for display type may be set wrong, or there may be a failure of the video card.
- Double-check the video display type settings in the BIOS.
- Troubleshoot the video card as follows:
You suspect a possible failure related to your video card
The video card appears to have failed. The PC may be refusing to boot up and the video card is suspected as the cause of the problem, or there may be an unusual error condition that implicates the video subsystem.
There are many possible causes for a video card failure. While an actual failure of the card itself is relatively rare, it does happen. More often, the problem is due to a configuration problem or resource conflict.
What to do:
- If you have recently assembled this PC, or you have recently performed an upgrade and changed the video card or its settings, reposition the video card in another slot and boot the system. If the system still balks at this, try your old video card if it still works and insert it into the same slot. If that works, put the new one in and see if you can detect anything on the screen. If there’s no evidence on the screen, in all probability the video card is bad or your system may not support it.
- Make sure that the video card is tightly and completely inserted into its slot. Try powering down, removing and reinserting the card and then rebooting.
- On older video cards, you may have a problem with “chip creep” on the card itself. If there are any chips on the card that are in sockets, gently but firmly press them into the socket. You may find that they had worked themselves loose and that this solves the problem.
- Watch out for resource conflicts, especially with PCI video cards that often take an IRQ channel already in use by the adjoining PCI slot they are inserted into, sometimes referred to as a shared slot. This IRQ usage is something that isn’t always well known, since before PCI, video cards using IRQs was less common. Changing the slot that the video card is in may solve the problem as this will cause the card to use a different IRQ (there could be a motherboard problem with the slot too, of course).
- If you have added a video card to a PC that originally had an integrated video card on the motherboard, you must disable this integrated video via a BIOS setting or motherboard jumper before adding the new video card. Otherwise, they will conflict with each other and neither will work.
- If possible, try the video card in another PC. If it works there, then the video card itself is probably not the problem, but configuration or a resource conflict is implicated. Of course, if the card doesn’t work in another PC, there is a good chance it is bad, but this presumes that you have set any necessary jumpers properly (if there are any).
- If you just added more video memory to the video card, try removing it and seeing if the problem goes away. If it does, then this means either that the video memory is bad, is the wrong type or was inserted incorrectly. Put it back into the video card and make sure you do this correctly. If the problem recurs, obtain a replacement for the extra memory. Make sure you are getting the exact memory that your video card requires. Make sure that if someone is adding more memory to the card, that they use identical memory to what was in the card before, and that it is all the same speed.
- Try disabling shadowing of the video ROM in the BIOS settings for the motherboard.
- If you are running a VESA local bus system, you may experience system problems if your motherboard is being run at over the nominal 33 MHz system speed. This includes potential problems if you are using a VESA local bus video card in a VLB/PCI combination motherboard running over 40 MHz.
- Some combination VLB/PCI motherboards have difficulties with using the VLB slot or slots that they include. In many cases the engineering on these motherboards is poor, and insufficient testing was done with both the PCI and VESA local buses running simultaneously.
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