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Re: IIe Backup

Robert Boucher wrote:
I have used a IIe forever. The current one has a 8mz Zip Chip, 1 meg Ramfactor in slot 6, CFFA card in slot 7 and an Apple high speed SCSI card in slot 5 used to make backups to a Zip disk. This setup has worked for many years; about three weeks ago the computer would not see the SCSI card. I could re-seat the card and it would work for a few days. I cleaned all the contacts, swapped positions on the Ramfactor and the SCSI card. Same problem. I have since used different Zip drives, many different Zip disks, swapped power supplies, etc. Now everything seems to function, Copy II+ can copy to, catalog and verify the Zip disk, and yet when I try to load a file from the Zip disk, I get a Cannot load file on those files that have been saved since the problem started. Older files on the disk, i.e., Expenses.04.DB, will load properly. 

This fact is the strangest of all!

I'm not familiar with a "cannot load file" error message.  Is that
what the application says when it can't find a file?  Can you access the
file with other applications, like Copy II Plus?  (I'm guessing that
you can.)

Have you run any error checking program on the Zip Disk--I'd recommend
Mr. Fixit in the ProSel 8 suite.  This will provide an excellent
"exerciser" function for the Zip Disk, drive, cable, and card.

I wouldn't be surprised if the diagnostic also worked, though your
history suggests that there have been intermittent problems getting
to the disk.

Run a good RAM test overnight, and try it without your RAMfactor card.
Many unusual problems can result from faulty memory, and, since the
Apple II doesn't do any RAM testing, strange behavior is usually the
first sign of a RAM problem.  Does everything *else* work fine on the
machine as long as the Zip Disk is not involved?
Also I THOUGHT I had the Zip Chip slot setting for the SCSI card set to high. Now on high the Zip drive locks up. The card seems to function (see above) on the normal setting. 

The High Speed SCSI card is completely compatible with the high speed
of the Zip Chip.  What the Zip Chip cannot handle is DMA, so that must
be disabled.

Something very strange is going on in this chain of hardware, and
it would be good if you could do some swapping to see if you can
"move the problem".  Try swapping Zip disks, Zip drives (if you have
another one), cables, and SCSI cards (if possible).

You have just reminded me of a possible (ugly) problem--the cache RAM
on your Zip Chip may be failing.  This can cause almost *anything* to
fail in strange ways--for example, code that runs correctly at one
address may fail at another!  Try resetting your machine with ESC
depressed to disable Zip caching and see if you can re-create the
problems.  If you can, then try again after removing the Zip Chip
and replacing the 65C02.

Many years ago, I had a string of Vulcan "crashes" that turned out
to be induced by failing Zip Chip SRAM.  There was a bad batch of
Zip Chips produced...
The slots in the IIe still seem to be fairly tight. If it is a motherboard problem, will a MB from a IIe case without a numerical keypad fit my present case with a keypad? 

It should, but first I'd try just moving the SCSI chain over to the
other //e and try it there.


Any other suggestions?


Be persistent.  Don't succumb to superstition.  The problem almost
certainly has a single cause that you can find.

-michael

NadaNet networking for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

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