Macintosh IIfx: How to Troubleshoot a Monitor/48 Card Problem


We have four Macintosh IIfx systems with the same problem. Each computer
is running System 6.0.5 with an Apple 4-bit video card and the Macintosh
Display Card 4*8. The cards drive a Macintosh High-Res RGB monitor and a
Macintosh Two-Page Display. The color monitors come up, but the Two-Page
Displays don't. The same configuration using the old Two-Page Display card
and the 4-bit card works fine. What's the problem?

Here is a troubleshooting sequence that may help you locate the culprit:

1) Start up with a known-good System disk with no INITs installed. Some
INITs cause problems with video.

2) Try swapping out the 4*8 card if you haven't already done so.

3) Using the original configuration, insert the 4*8 (the card driving
the Two-Page) into a different slot. There might be a problem with the
bus lines or the slot itself.

4) Swap the logic board, if the slot or bus is the problem.


Published Date: Feb 18, 2012