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2.698 bytes |
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Document ID: GSMH-3A5H5N |
IBM PC730/PC750 - Cannot see POST via Micro Channel video adapter
Applicable to: World-Wide
Symptom:
Installing a Micro Channel video adapter into a Micro Channel PC 700 renders the POST invisible when the monitor is attached to the video adapter.
Problem Isolation Aids:
Removal of the Micro Channel video adapter plus reconnection of the monitor to the planar video port restores visibility of the POST. Problem only affects Micro Channel PC 700 systems. ISA PC 700 systems are unaffected.
Fix:
A Video Feature Bus (VFB) cable is required, option part number 06H6727. This connects between the planar VFB pins (adjacent to the S3 864 video controller chip) and a corresponding set of VFB pins on the riser card (below slot 1). This cable will be generally available within Europe as of 31/08/95.
Note:
Only Micro Channel video adapters will require the VFB cable. Examples of such adapters include the IBM Image Adapter/A and various OEM adapters such as those from Cornerstone.
The reason that the cable is required for Micro Channel PC 700 (and not for PS/2) is that PS/2 is designed as Micro Channel throughout. In contrast, Micro Channel PC 700 systems have the same PCI/ISA planar that is found in ISA PC 700 systems. Micro Channel adapter expansion is provided from PCI using a bridge chip set that resides on the riser card itself. For reasons of planar commonality and other design constraints, it was not possible to route VGA pass-through via the planar riser socket, requiring a separate route instead; hence the VFB connectors.
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Search Keywords |
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Hint Category |
Adapter Cards, Video | |
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Date Created |
02-10-95 | |
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Last Updated |
27-04-98 | |
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Revision Date |
23-04-99 | |
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Brand |
IBM PC | |
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Product Family |
PC 730, PC 750 | |
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Machine Type |
6876, 6886 | |
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Model |
Various | |
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TypeModel |
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Retain Tip (if applicable) |
N/A | |
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