My Miggie 2K

[Damion]

I acquired the 3.1 ROM for the unit and I am looking to install a new RTC battery.  The old one having been removed to prevent PCB damage.  I have been advised to perhaps use 2 AA batteries, but wanted to find out if anyone has ever used a button cell and what might be involved in installing that kind of solution.  For example:  would I need to install a diode to insure that the system does not try to "charge" the CR2085?  Should I worry about this same kind of issue with the 2AA cell holder idea?

My solution was to install a 2032 coin socket directly on the motherboard, then remove R803 (charge limiting resistor for the original Ni-Cad) and install a germanium diode... I used a 1N60 IIRC. Looks nice, and very inexpensive. I'll post a pic of it later this eve.

[Damion]

So I guess the remaining question is, do you place the diode on the postive lead or the negative lead...I assume you want the direction of current flow towards the mainboard if on the positive lead preventing the charging circuit from being able to reverse the polarity if the voltage drops?  I have not decided whether or not I want to mount the holder on the mainboard or attach leads, that I will determine at a later time.

On the positive lead, with the stripe facing away from the battery. Going to try to get that pic up today... camera died, so I have to bum my gf's.

[Damion]

Had the cover off of my A2K today, but wasn't able to get a good shot without removing the CPU card and drive cage. Fortunately, the posted pic pretty much shows everything. The only thing I did differently was to install the 1N60 diode at R803, with the stripe facing away from the drive cage.