6400 PowerPc Performa Pram Battery issues - remove for storage?

The risk of running the battery completely flat is that it may leak chemicals onto the motherboard and ruin it.

Jim [Appaloosa Mac Man] will tell you from his experiments with hundreds of Macs with dead batteries that a battery is not required to start most Macs if you learn a trick or two -- but it does make it more convenient in daily use.

I removed the batteries from my retired 6400s and 6500s, primarily to prevent leakage (as Grant has mentioned). I've seen the corrosive damage to motherboards, caused by leaking alkaline solution from those batteries. When I periodically start up the 6400/6500s, I reset the date & time so that any file modifications have the correct information. Other than that inconvenience, the computers function normally.

Without the memory battery, the Mac cannot retain it's PRAM settings. Some Macs will boot without the battery, but many won't. For long term storage, it's best to disconnect the battery connector. New batteries are not too expensive, or you can make a 4.5V substitute. See Mac PRAM, NVRAM, CUDA/PMU & Battery Tutorial

 Cheers, Tom

Lowell,

As Grant indicated, I choose to spend $15 on G3 computers instead of PRAM batteries. But, I conceed that for daily use, nothing beats a fresh battery.

Let me take an entirely different approach. I prefer external SCSI towers for data backup instead of trying to keep stored CPUs constantly up to date.

This website has new and expensive models.

http://macgurus.com/productpages/scsi/mgscsienclosures.php

I look for used enclosures at government surplus outlets ( yes, that includes your army surplus stores). The last 4 bay tower with four drives was $20.

Finally, if you are really worried about a battery leak, take a plastic magic marker brand felt pen, cut it down to length, solder wires to salvaged battery end caps and create your own remote PRAM battery that is away from the motherboard. The plug fills the onboard battery holder and a Radio Shack (Tandy for you guys down under) battery holder with long wire leads goes in a place of your choosing.

It is a crazy world where a nice computer like the 6400 costs less than a battery.

Jim

If you press the CUDA Reset button in a Mac that allows access to it with the System running, it will do an immediate [panic] power off. Not what you want.

On some Macs, if you run the battery down really low, you have a hard time getting a solid reset using any means. Anecdotes support shorting the contacts of the EMPTY [NO battery present] battery pins/socket with a metal object to drop the voltage all the way to zero.

Hi folks.

After buying a third 4.5V battery for my Performa 6400/200, I got fed up when it too died after only a year of use. Not wanting to spend another 18$ Can for another 4.5V battery I decided to try another approach.

I bough a battery holder able to hold 3 AA size batteries. These three 1.5 V batteries give 4.5 volts when installed in serie.

I cut the two wires from the 4.5V battery case and attached these to the wires that where already attached to the new battery holder, making sure to respect the polarity.

When this was done, I was able to reconnect the small plug on the mother board, slide this in place and get the battery holder outside the computer case (on the back of course). I simply threaded the wires through an opening before connecting them.

The net result is a battery set that last for a long time and that allows quick and easy batteries change since I do not have to open the computer to do it. So far, after two years, it still works well. The computer is now nine years old but it works perfectly.

Performa 6400/200 Mac OS 9.2.x RAM 136 Megs, external 6.3 Gigs Hard Drive

If you routinely disconnect the 6400 from the electrical outlet, a battery pack consisting of (3) 1.5-volt AA lithium batteries would last even longer, when repeatedly called upon to preserve the PRAM settings.