arra@inmet.inmet.com (04/13/91)
I have a Z-248 with a memory card which has a problem, but I have no
documenation for it.
Memory Card:
The card contains 128K conventional memory, rounding 512K up to 640K.
This is with soldered 64K chips.
It also has 1 Meg extended memory, base address at 1MB.
This is with 512K soldered 256K chips, 512K socketed 256K chips.
The card has the connectors for the extended Zenith slot.
There are 3 2-pin jumpers labelled J403, J404, & J405.
The writing on the chip side of the board says:
85-3260-20 072286 Memory Board (then in big, 7-segment LCD-like
characters, 0787)
The back side of the board says: 050686 85-3260
The problem: the 128K contains a memory parity error, which occasionally
occurs with software (presumably which accesses memory that high),
and repeatedly occurs (at the same address) when I run the
ROM-resident Zenith memory test. This test says to replace chip U407,
which I did. However, the test still reports a memory parity error
so I no longer trust the ROM test's chip identification.
The 1 Meg extended memory is OK. I would like to either
1) fix the "parity" error on the 128K, or if I can't accomplish that,
2) disable the 128K and still use the 1 MB extended memory.
I guess that the jumpers might be able to re-configure the board to accomplish
2), but without documentation, I'm lost.
Does anyone have any user documentation, or board schematic, for this board?
Thanks in advance,
=====================
arra@inmet.inmet.com
Arra Avakian
Intermetrics, Inc.
733 Concord Ave
Cambridge, MA 02138
(617)661-1840 x4500
=====================johnh@eecs.cs.pdx.edu (John Harris) (04/17/91)
In article <34600002@inmet> arra@inmet.inmet.com writes: > >I have a Z-248 with a memory card which has a problem, but I have no >documenation for it. > Arra Avakian, If you have not yet found it, I have the Docs. Please call me! PS... I have 22 of the Z-248, all with memory cards, and your right, the diag's cannot be trusted unless you REALLY know what your doing. (503) 725-4294 PST 9am - 5pm John Harris CAD Lab Supervisor Portland State University