Re: Serial-Pro card in a coma!

[jdb8042@tam2000.tamu.edu (John Donald Baker)]

In article <3ujemm$lsn$3@mhafm.production.compuserve.com>,
Michael Gasperschitz  <100255.523@CompuServe.COM> wrote:
>replace the cmos clock chip.
>
>grab it from an old 286 motherbooard. They use generally the 
>same.
>I had the same problems

My problem turned out to be what I expected.  The Varta MemPac
3.6V cell was now registering 2.88V and this condition was enough
to keep the 6818 clock chip "confused" even when system power
was on.  I removed the old power cell and everything operates normally.

Now my only problem is that I need to know exactly what kind of cell
it was.  NiCd?  Lithium?  What?  I want to replace it, but don't know
where to get an appropriate replacement.

In the interrim, I scavenged a perfectly good 3.6V lithium cell from
a dead GRiD Systems' 286 laptop and soldered it in in place of the
old Varta cell. My SerialPro now retains its setup but the clock
runs slow when run by the battery (system power off).

Am I headed for disaster with this arrangement?  Is a lithium cell
appropriate for use on the Serial Pro?

(As for replacing the 6818 chip:  I'll have to buy one as I don't
have access to any dead 286 motherboard except by special, lengthy
travel.  And then, the dead 286 motherboards available have been
stripped of everything I could possibly use except those parts that
are soldered into the board--and I haven't had much success desolding
parts without destroying them.  I have a Motorola 146818A chip, but
it didn't work in the SerialPro.  I don't know if it's bad or if the
SerialPro requires the plain 146818 (the "A" and "non-A" versions have
different access methods and different requirements for battery power).


John D. Baker ->A TransWarp'802'd Apple //e CardZ180 Z-System nut //
Internet:  jdb8042@tam2000.tamu.edu, @blkbox.com, jdbaker@taronga.com
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http://tam2000.tamu.edu/~jdb8042/