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MacFox

32-bit Addressing on Centris 650 without PRAM battery

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Hello,

 

I recently added a Centris 650 to my collection and am having a bit of a conundrum regarding 32-bit addressing.  I removed the PRAM battery the first day I got it.  It wasn't leaking, but I didn't want to take any chances.  Unfortunately, 32-bit addressing must be a PRAM setting because when booting up from a cold boot under 7.5.3 or 7.5.5 24-bit addressing is on instead.  I tried using a control panel named PRAM Auto-restore, but it didn't help much.  It made it so that the 32-bit addressing switch was turned on, but I still had to restart the computer in order for 32-bit addressing to actually work.  I tried upgrading to 7.6.1, which turns 32-bit addressing on by default, but when I do that the Mac restarts itself during startup.  What happens is: chime -> happy Mac -> black screen -> chime again -> happy mac again -> boot proceeds as normal.  This also happens under 8.0 and 8.1.  I should note that I formatted the drive, a 500 MB Quantum, using the patched version of 7.5.3's disk tools.  The 8.1 installer reports my drive as a non-apple drive and refuses to update the disk drivers.  8.1 will still install though.  HD SC setup on the 7.6 and 8.0 boot disks can't see the drive at all. 

 

What I am asking is this:

 

1) Is there any way under 7.5.3 or 7.5.5 to make it so that 32-bit addressing is turned on by default without having to restart?

 

2) If I must upgrade to 7.6.1 or above, is there any way to fix the issue of 7.6.1 and above restarting during the startup process or is that normal for those OSes?  Is there a third-party tool I can use to update the hard disk drivers if necessary?

 

Thanks in advance

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Just to be clear, you're running the system without a PRAM battery?

There are a lot of unpleasant side effects to no PRAM battery in that vintage of machine, you might want to install one.

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1 hour ago, Gorgonops said:

Just to be clear, you're running the system without a PRAM battery?

There are a lot of unpleasant side effects to no PRAM battery in that vintage of machine, you might want to install one.

Yes I am running it without the PRAM battery.

 

Any recommendations for brands available today that are the least likely to leak?

Edited by MacFox

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21 minutes ago, MacFox said:

Yes I am running it without the PRAM battery.

 

Any recommendations for brands available today that are the least likely to leak?

search "3.6V half-AA" and it should get you some good results. Saft is a common brand that's decent in reliability. Others might chime in with their own experience.

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I recommend buying a new one in order to avoid leaking. Most of the PRAM batteries that have leaked are 20-30 years old.

 

In addition, it would be a reasonably good practice to remove the batteries before storing a system long-term, and open the system from time to time (yearly, maybe?) to inspect the battery.

 

As to 7.6.1 and 8.0/8.1's automatic reboot behavior: My guess is this is happening because the system (as you say) boots into 24-bit mode by default, then reboots into 32-bit mode so 7.6 and 8 can run. If you install a PRAM battery, the system should, under most circumstances, not reboot itself during power on.

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As Cory notes, it's a good idea to remove the PRAM battery before you store the system for a "long time". This would apply to any brand.

 

Under normal circumstances a battery that has enough charge to do its job isn't going to leak. "Battery Explosions" are generally the result of letting a battery sit after being completely drained for weeks/months/years. If you're using the Quadra and the battery is holding PRAM contents it's *very* unlikely you'll just wake up some morning and find it's gone nuclear.

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Just wondering, would using a DC supply to supply 3.6V to the battery terminals eliminate the need for the battery?  If so, one could conceivably create an adapter to step down 5V off of a USB connector, and have a port for it in a spare NuBus slot or something. 

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It should.

 

The biggest concern, I would think, is that the actual power draw should be fairly low, given that the first battery on most of these things lasted ten to twenty years, depending.

 

You'd need a USB adapter (if you were to use that) that doesn't try to be smart by turning off power with a draw below a certain amount.

 

With that in mind, it might be easier just to use a real PRAM battery, or some kind of battery-based alternative.

 

As a child, I avoided doing the pizzabox power-toggle on a 475 by taping two AAs together with some random wiring I had and attatching that to the terminals, I don't know if that would be good enough in this instance. I was experimenting with re-casing the machine at the time, but I later ran the batteries out the back of the machine wired through the PDS slot.

 

 

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Really, those batteries are not that expensive, and if you're worried about leaks just remove them before storing the machine for any length of time. Unless you get a really terrible battery the machine should start showing symptoms of having a dead battery well before the battery gets acidic enough to start corroding. Remember, these machines trashed by exploding batteries have in many cases been sitting literally for decades.

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One thing I noticed while removing/replacing these batteries is that if you’re not careful, the plastic on the top half of the battery holder can snap off.

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