Search Posts:

Replacing the Internal Battery

View Entire Thread

Return to Threads

  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

Found these:




Buy a Commodore Computer Poster

Popular Topics and FAQs

  • Commodore B Series Tips and Tricks
  • Aerocomp TRS 80 M 1 Expansion Unit DDC
  • Items Wanted
  • Lobo Max 80
  • Zenith Z-19-CN
  • Prototype PET 2001 photo
  • Using Toggle Switches to Analyze Memory
  • Commodore Disk Archive Project
  • PET 2001 Prototype at Gametronics 1977
  • Jim Butterfield Photo
  • IMSAI 8080 With Processor Tech. Cutter
  • Secrecy is the keystone of all tyranny
  • Cromemco System Three
  • Northstar Horizon - Boot Problem
  • Computer History and Restoration Links
  • Commodore BX-256-80 - 8088 Co-processor
  • S-100 board testing with Z-80 ICE
  • Donner 3500 - an early portable computer
  • Digital (DEC) PDP 11/05 NC Assembly
  • Univac 1219 rescue
  • Fido BBS listing node list 6-13-1986
  • PDP 8e
  • MITS 88-2 SIO (2SIO) for BASIC
  • Visual Technology Inc Model 1050
  • Amiga 2500 Restoration
  • The Evolution Of IBM Computers
  • Replacement teletype print hammer head
  • Archiving and Copying Software 101
  • Computers Built 1940 - 1950
  • CBM B-520 (a.k.a B256-80 or B500 256)
  • RCA COSMAC Microkit
  • Commodore 64K C-116 Mods
  • MITS 8800b Turnmon 9600 baud
  • Catweasel, 8in and 5 1/4
  • Raspberry Pi as Gateway to Internet
  • Digital PDP11 late 1969 early 1970
  • PDP 11/40 72 inch cabinet model
  • PDP 11/40 Industrial 11 model
  • Digitial MicroVAX 3100 30 System
  • Digital VAX 4000-200
  • Commodore 64 / 1541 DRIVEKNOCK
  • Booting the System Using RL02 drive
  • PACS: Reflections by Kathleen Mauchly
  • Tele-Graphic Computer Systems Inc.
  • Commodore B Series SID Jukebox?
  • Installing Core into PDP 11/40
  • Setting Up OpenVMS 7.1 DNS CLERK
  • Felt-Tarrant Comptometer Model J
  • NextStation Color
  • Digital Rainbow (PC100-B2)
  • 1970 Compusad Compulogical Tutor
  • Archiving Papertapes Using DSI NC 2400
  • 1976 P.C.C. Features the MAI JOLT 6502
  • 1961 Beckman DEXTIR Computer
  • UNIVAC 1 and UNIVAC File Computer 1
  • Past Issues:

    FamiCom front

    This image was selected at random from the archive. Click image for more photos and files from this set.