🚀 go-pugleaf

In <4nk772$ofc@news.rhrz.uni-bonn.de> mjr@geo.uni-bonn.de (Michael Ritzert) writes:

>Is there any chance to prolong the life of the NVRAM chip with an external
>backup battery?

>My idea:

>add a battery (4.5 V) parallel to the +5 and GND connectors of the MOSTEK
>Chip (does it use its internal battery or the power supplied by the board
>while the machine is running?).

>In addition you have to seperate the connection battery/board by a diode.

>Any chance that a construction like this will be possible and will work?

Yes. I have an SS1 here in which the NVRAM battery had failed when I 
received the machine. I had no record of it's 'official' serial number or 
ethernet address, so I have to make them up based on a few simple rules, 
but that's not relevant to this discussion...

The Mostek 48T02 NVRAM/RTC has a small lithium battery and an oscillator
in the satellite that sits on top of the chip itself. I found a discussion
of how to connect an external cell to the battery terminals in one of the
FAQ documents at the Sun-3 Archive. 

Mark Henderson's NVRAM/HostID FAQ might also include how to do this, but I
haven't seen anything about it there.

I can't remember the URL's offhand, but I have links to both of these
places on 'http://www.zeta.org.au/~craig/srk_sunfaq.html'. 

You need to use a 3 volt cell, not a 4.5 volt one. I had a few spare 3
volt lithium cells out of old calculators, so I used one of them, and
hacked up a battery holder out of a 3.5 mm phone socket and a small piece
of veroboard. The assembly is stuck on top of the NVRAM with some 
double-sided tape. It's ugly, but it works. 

The downside of my approach is that it gets in the way of any cards I want
to plug into Sbus slots 1 or 2, but since the SS1 is my gateway, there's
nothing plugged into them, so it's ok. 

Regards,

Craig.
-- 
             Craig Dewick. Send email to 'cdewick@jedi.apana.org.au'
                 The Core Matrix Foundation - Sydney, Australia
                        http://jedi.apana.org.au/core.html
 Always striving for a secure long-term future in an insecure short-term world