portcommodore.com PET/CBM FAQ

MODELS OF THE PET/CBM - MOTHERBOARD SERIES

The PET line was Commodore's first computer line after purchasing MOS Technologies, the primary design of the computer (as well as its microprocessor, the 6502) was by Chuck Peddle. The line was labeled in series' the first series, the 2001 series, the European 3000 series, and the modern 4000 and 8000 series, and the final single unit 9000 series which is the SuperPET. In Europe due to trademark problems with Phillips Electronics commodore had to drop the PET name early and used the CBM (Commodore Business Machine) abbriviation instead - in the U.S. CBM was used to on the 'business class' PETs and PET/CBM disk drives and printers.

9" monitor units (40 column x 25 line character only display):

PET 2001 series:

Original PET:

• Steel case
• Internal 'datasette' cassette tape drive
• Blue on black 9" display
• Small 'calculator style' keyboard
• Small shipment with 4k, most with 8k RAM
• Original ROMs
• uses MOS 6550 1K x 1 RAM chips
• the Prototype PET has a carved wood case

    2001 4k/8k MOTHERBOARD (9" CRT)          
            IEEE user tape #2
     +------####-####--##-+
     !                    #
     !                    #
     !                    # exp
     !                    # bus
     !                    #
     !                    #    2000 Series
     !                    !       circa 1977/78  Max RAM - 8k
     !       (2k) ROMS    !       [w/daughter board exp to 32k shown]
     !      F F E D D C C !
     !      8 0 0 8 0 8 0 !
     !                    !
tape #       RAM MEMORY   !
 #1  #                    !
     +--------------------+

PET 2001/CBM 3000 series Large Keyboard PETs (no more internal datasette drive):

• Many steel cased, some have molded plastic tops.instead.
• Most had a clearer green on black display
• Used more popular 2114 2k x 1 RAM chips

PET 2001/3000 xN (x=8,16,or 32 depending on amount or RAM it was shipped with)

• Full-size key keyboard w/PET graphic symbols imprinted on keys
• Upgrade ROMs
• Later versions had 4.0 ROMs installed

PET 2001 xB (labeled as CBM, Commodore Business Machine)

• Full size xx key keyboard (no graphics symbols printed on keys)
• Upgrade ROMs (powers up in upper/lower case mode)
• Later versions had 4.0 ROMs installed

PET/CBM 40xx Series (PET= N keyboard/ROM, CBM= B keyboard/ROM, xx= RAM)

• 4.0 ROMs (note: there are variations between the 9"CRT and 12"CRT 4.0 ROMS!)

    2001, 3000, early 4000 SERIES MOTHERBOARD  (9" CRT)
             IEEE user tape #1
     +------####-####--##-+
     !                   #!
     !                   #!
     !                   #! exp
     !        ROMS       #! bus
     !    F E D C B A 9  #!
     !                   #!    3000, 4000 Series
     !                    !       (3000 series is European version)
     !                    !       circa 1979/80  Max RAM - 32k
     !                    !
     !                    !
     !                    !
tape #      RAM MEMORY    !
 #2  #                    !
     +--------------------+

12" monitors - updated video controller (prone to the 'killer poke')

• Internal piezo speaker, audible startup, and right margin sound.
• 4.0 ROMs (note: there are variations between the 9"CRT and 12"CRT 4.0 ROMS!)
• Expanded display control 'escape codes' and bell (CHR$(7))

PET/CBM 40xx (PET= N keyboard/ROM, CBM= B keyboard/ROM, xx= RAM)

• 40 x 25 display, upgradable to 80 columns
• lower case available by CHR$(14) which also changes line spacing.

80 column series (can be set to 40 column mode via software.)

CBM 80xx

• 80 x 25 display, powers-up in upper/lower case.
• business xx key keyboard
• later versions had 64k ( total 96k RAM) expansion board options.
• 4.0 ROMs

PET SP9000 SuperPET (or Micro Mainframe)

• 80 x 25 display
• 6809 co-processor board
• 96k RAM
• True RS-232 interface
• Multiple character sets (for APL, etc.)
• Availability of disk Based languages

CBM 200 / 8032 SK

• Same as an 80xx series CBM unit with rounded case, not sold in the US.

CBM 8296

• Same features of the 8000 series but with built-in 64k memory expansion,
• rounded case and detached keyboard. This unit was not sold in the US.

    4000/8000 SERIES MOTHERBOARD (12" CRT)
            IEEE user tape #1
     +------####-####--##-+
     !                  # # tape
     !                  # #  #2
     !  R       exp bus # ! 
     !  A                #!
     !  M             9  #!
     !                A  #!     4000, 8000 Series
     !  M          R  B   !        circa 1981     Max RAM - 32k*
     !  E          O  C   !       [8296 layout not shown]
     !  M          M  D   !
     !  O          S  E   !
     !  R             F   !
     !  Y                 !
     !                spkr!
     +--------------------+

SUPERPET DAUGHTER BOARDS
ON 4000/8000 SERIES MOTHERBOARD
(DAUGHTER BOARD CONFIGURATION MAY VARY)

Teacher's PET

This unit was usually a 2001 series PET which was re-labeled with "Teacher's PET, Donated by Commodore Business Machines"

The story behind these in many US schools (at Least in California, where I know of it) Commodore had a promotion where if schools bought 2 PETs the third would be 'donated by Commodore. This was a tax write-off and marketing plan for the company similar to Apple's promotion of "an Apple for every school".

Educator 64/4064

This is actually a Commodore 64 in a PET case, thus beyond this FAQ.

Various PETs w/other Commodore computers

(for size comparison)

(note bottom-rightmost three PETs with Calculator, business (B) and graphics (N) keyboards)