Re: Z-RAM ultra 2... replacing the battery?

[Gary <dontyouspamme_vengefultacos@comcast.nospam.net>]

 Wayne Stewart wrote:
> 
>>I'd think that if it wouldn't work after a few hours, more time isn't
>>likely to help. Having a rechargable battery, you'd think that the
>>charging circuit would power the clock even with a dead battery. If
>>you can, it'd be nice to check the voltage at the battery leads when
>>the IIc is running in case it's the charging circuit that's not
>>working

Checking the leads on the battery would be problematic when running, since
the card sits face up in the //c, and has to be socked down, since it
connects into the MMU and CPU sockets on the motherboard. 

 Michael J. Mahon wrote:

> That's right.  The circuit operates from the battery _only_ when
> the computer power is off.
> 
> That means that the software is choking because the clock
> currently contains an invalid date/time.  Try running the clock
> setting software and see if that fixes it for a warm boot (since
> the battery is still not known to be working).

I had booted up the clock setting disk before, and the setting software
crashed into the monitor, too. Just now, I realized that there was the off
chance that the setup disk would actually run the clock driver before it
ran the setup program... (which, it turns out, it does... sorta stupid
design there) so I booted up from another disk, then ran the clock setting
software directly. And it worked! The clock had a date somewhere in the
year 52. I reset it to the current date and time, then did a warm boot. 

The clock reading software was able to run without crashing, but it read
back the exact date and time I had set with the clock setting program. 
After about 20 minutes, rebooting into any of the disks that has the clock
driver still resulted in the exact time I had set being read. So it looks
like the clock accepted the data, but won't actually update it.

Next I tried a quick powercycle to see what would happen. Loading the clock
driver results in the crash to the monitor again. Running the clock setup
software also ends up in a crash to the monitor, with the time on the
screen showing a date in 04, but a different month and random time. Just
before the crash, the time flips around madly, as if the software is
reading from a spinning clock.

So... I'd guess I'm looking at both a dead battery and a screwy clock chip?
A bit of googling turned up a PDF version of the Z-RAM's manual
(http://tinyurl.com/6xn6l), which identifies the clock chip as an OKI
6242B. The spec sheet I found:

http://www.okisemi.com/jp/datadocs/doc-eng/msm6242b.pdf

says it has an onboard crystal... so I wouldn't be anle to swap out a
crystal to see if that's the culprit. I'm not able to discern many other
relevant details from the sheet (it's been almost 20 years since I flunked
my last EE class ;-). The datasheet is dated 2002, so I assume the part is
still made... perhaps I could just buy another one and swap out the
existing chip (I think everything on the board was socketed, so I wouldn't
have to tax my limited soldering skills). 

Thanks for all the help and suggestions so far!

Gary