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