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Replacing the Internal Battery

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  by Bill Degnan - 12/04/2017 22:18
Access the Next> ROM monitor by hitting the Control + ~ key while the system is attempting to boot. Pictured is an exploratory session to check the system configuration and to display the available commands within the monitor. Pretty straight-forward. Click image for larger view.

I was curious to see if one should back up the system parameters stored in the internal battery-powered ROM while the battery is still good to avoid having to guess how to restore the system setup after losing the battery BIOS or whatever you call the internal configs stored in battery-powered ROM.

Next> p
(initiates the system inspect/setup routine)

I believe the default is to boot off the network (" en ") rather than the scsi drive (" sd "), so the first thing I predict I will have to do after changing the battery (or if it dies) is change the boot device to sd (scsi disk). The image above shows the computer's configs as they are now, in proper working order.

When I probed the battery with a volt meter I found it still had 2.8 volts, fading but not yet dead. It's not a rechargeable so it's less likely to leak. Still it will need to be changed eventually as do all internal computer batteries. I learned the hard way from my experience with an IBM AT that removing the internal battery might cause unforeseen problems, best to know what you're dealing with before you start.

Yup. It's actually easier than I thought. Most of the configs are stored on the hard drive, so when you replace the battery get to the Next> prompt (Control + ~) and enter the command help. That will show you all of the commands you can use, or just do this:

Next> p
(to inspect/modify configuration params, follow the prompts, leave the default values in most cases.)

When asked for the "boot command" value, assuming you're using a SCSI hard drive, enter:


If you have more than one drive or a different boot partition you'll have to be more precise, but that's pretty much it, the rest of the configs are automatic.

When you're done, reboot.

Next> b sd

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