🚀 go-pugleaf

In <829242141.26919@plumgate.demon.co.uk> Andy Michael <andy@plumgate.demon.co.uk> writes:

>I need a couple of replacement NVRAM chips for machines that have exhausted
>the lithium batteries on them.  One is for a 4/350, which seems to a Mostek 
>MK48T02B-25.  The other is for a SparcStation 1+ (or 4/65, if you prefer)
>which may or may not be the same chip - I can't tell because Sun have put
>a large sticker over the top of it.

>If anyone knows of a source of these in the UK, I'd be grateful.  A credit
>card over the phone job would be ideal.

Dallas Semiconductor make a pin- and function-compatible equivalent to the
MK48T02. It's called the DS-1642. You can order small quantities direct
from Dallas by phoning them and giving them credit card info.  Check their
web page - 'http://www.dalsemi.com'. 

Mark Henderson's NVRAM/IDPROM FAQ (not sure of it's URL - check my FAQ
page at 'http://www.zeta.org.au/~craig/srk_sunfaq.html' for a link to it)
mentions that the Dallas part doesn't seem to work properly in all
machines that use the Mostek part. I've used DS1642's in some SS1's
without any trouble, and soon I'll be dropping one into a 3/80. 

>Incidentally, the SparcStation 1+ now claims to have forgotten its host id
>and ethernet address as a result of the battery failure.  Are these stored
>somewhere other than the NVRAM chip, and does anybody know how I might
>restore them to a new chip?  Presumably there's a version of the "eeprom"
>command which writes to the part of the NVRAM which is not normally
>accessible?

As long as you have a record of these values, there are ways to write to a
new NVRAM to restore the settings. It depends on if you know what they are
or not, and if you have the NVRAM data saved in a file or not. 

Before I could get some 1642's, I hacked up a holder for a 3 volt lithium
calculator battery for a drained 48T02, and milled away at the resin at
the right end of the chip until I could solder some wires from my
freshly-engineered battery holder to the now-exposed battery terminals
poking out of the plastic package of the 48T02! It's nasty, but it works. 
I wouldn't recommend doing this to everyone though, since I needed to get
a machine going in a hurry, and it's much neater to get a new chip.

Regards,

Craig.
-- 
        Craig Dewick - craig@zeta.org.au - http://www.zeta.org.au/~craig  
                          Located in Sydney, Australia.
          Sun Ripened Kernels - http://www.zeta.org.au/~craig/srk.html
                Surplus and pre-loved Sun Microsystems equipment.