[comp.sys.ibm.pc] InBoard/386 problems

jcmorris@mitre-bedford.ARPA (Joseph C. Morris) (05/06/88)

I've recently acquired an Intel InBoard/386 card for the purpose of getting
reasonable response time from an aging low-serial PC (the original 5-slot
variety).  So far, I haven't been able to get it to run the basic diagnostics
at power-up.

The symptoms don't make much sense to me.  It seems to work fine as
long as I don't  have the expansion chassis transmitter card installed, but
once the card goes into the machine (even if the expansion box isn't connected)
then the EGA fails its diagnostics.  The problems occur with any reasonable
settings of the dip switches on the transmitter.

The board inventory consists of an IBM floppy controller (original with the
machine), the InBoard/386, an IBM EGA with 256K graphics memory, an Intel
AboveBoard with 2M, and the IBM Expansion Adapter transmitter.  The problem
occurs with or without the AboveBoard card installed.  The expansion box
inventory isn't significant since the failure occurs with it disconnected.

I've got a new 150W power supply.  Reinstalling the 8088 and 8087 chip returns
the system to full (if slow) operation, so it doesn't seem to be damaged
boards unless it's the InBoard itself.  Normal IBM diagnostics run fine (with
the transmitter card removed) except that the cassette interface test fails
as expected.

Intel is looking at the problem, but apparently hadn't run into an attempt to
install the card on a unit with an expansion chassis and so far seems to be
rather baffled.  Does anyone in NetLand know of any successful or unsuccessful
installations with this configuration?