Sothius' Home of Ancient Microcomputers - Commodore 64 (ASSY 250425)

Commodore 64 (ASSY 250425)

Commodore 64 ASSY 250425 (64 KBytes)

A C64 based on the ASSY 250425 board ('version B board') with original box in the background, and power supply to the right. This machine has been built in the United Kingdom. If you compare its case with that of my Western Germany-produced ASSY 250407 machine, you'll note that apparently different plastics have been used in C64 production
(picture copyright by M.A.Grundke)

Specifications

Name
Commodore 64
aka 'C64-I', 'breadbin', 'bullnose'

Codenames 'VIC-30' (while in development)

Made by Commodore Business Machines (CBM)

Released
1984
this particular machine was produced in 1985, as indicated on its chips
the first version C64s (ASSY 326106/ ASSY 326298-01) appeared in January 1982

Serial-No.
U.K. B 2157824
Box also says MADE IN UK

Board-info
P/N 251470-01 REV.B
ASSY NO. 250425
(C)1984 COMMODORE INTL
COMMODORE 64
ASSY-NO. 250425
in this ASSY 250425 ('C64 version B') board's design, locations for some of the chips such as SID, color SRAM and PLA, have changed. Also, some TTL (near VIC-II) has been replaced by a MOS 8701 clock generator for cost-reduction ('improved system clock circuit design')

CPU MOS 6510
6502 code-compatible but with
8 bit bi-directional I/O port and
256 bytes SRAM integrated
produced in NMOS-process
there are also machines of that board revision making use of MOS 8500-CPUs, implying that MOS started HMOS-2 production that year (1985), shortly before becoming CSG (Commodore Semiconductor Group)

Speed 985.248 KHz (PAL)/ 1.0227 MHz (NTSC)

RAM
64 KBytes:
8 pcs. Motorola MCM6665BP20 (64Kx1)
additional Toshiba TMM314APL-3 (1Kx4 SRAM) for storing screen color data ('color RAM')
up to 16 KBytes can be addressed as video-RAM by VIC-II
expandable to 576 KB/ bankswitched (CBM 1750 RAM-expansion)

ROM/ Native OS C901226-01 Commodore BASIC V2 (8 KBytes)
C901227-03 CBM C64 KERNAL Revision 3 (8 KBytes)
C901225-01 character generator ROM (4 KBytes)
In this early C64 board-layout, BASIC and KERNAL were stored in two separate ROMs

Keyboard/ Layout 66 keys/ US (QWERTY)

Graphics MOS 6569 'VIC-II' ('Video Interface Controller')
MOS 8701 clock generator
Max.Resolution: 320x200 pixels ('high-res')
40x25 attribute cells, each 8x8 pixel in size
2 colors per cell (background, foreground)
Max.Colors: 16 ('multi-color' @ 160x200 pixels)
40x25 attribute cells, each 4x8 pixel in size
4 colors per cell (3 foreground + background)
most common mode for games
with tricks (such as combining two multi-color modes with interlace, or forcing BAD SCAN LINE at each raster line), it is possible to use up to 16 colors per attribute cell, or to increase the palette to 128 colors. However, since these modes all have major drawbacks (such as interlace flicker, extensive CPU- and VIC-cycle usage), they're mostly used for demos
furthermore, VIC-II can create up to 256 movable display objects ('sprites'), 8 per line, and max. 21x24 pixels each
Text: 40x25 characters with graphical charset
this is a PAL-B version; the NTSC-M version of VIC-II was the 6567. Additionally, there were 6572 (for PAL-N) and 6573 (PAL-M)

Sound MOS 6581 'SID' ('Sound Interface Device')
3 independant voices, each with 9 octave range (0.1Hz-4KHz in 0.059Hz steps)
4 waveforms (sawtooth, triangle, variable pulse & noise)
programmable ADSR (attack, delay, sustain, release) envelope generator
programmable filter, independantly selectable for each voice (low pass, high pass, Band pass, notch outputs)
master volume control

Media
standard Audio-cassettes (via CBM VC-1530 'Datasette')
5.25" disks, 170 KBytes/ disk (serial drives; CBM VC-1540, CBM 1541, CBM 1570 and so on)
later: other CBM-drives via IEE488-interface
later: 3.5" disks (CBM 1581), 800 KBytes/disk
later still: harddisks up to 30 MBytes

Input/ Output 2x MOS 6526 'CIA' ('Complex Interface Adaptor')
MOS 906114-01 'PLA' ('Programmable Logic Array')
2x 9 pin joystick/ mouse/ paddles/ lightpen
44 pin female edge conn. cartridge interface
8 pin DIN-41524 audio/video (earlier versions had 5 pin video)
6 pin round-DIN CBM serial IEC-bus (printer or up to five diskdrives)
12 pin male edge conn. CBM cassetteport

24 pin male edge conn. 'user-port' (8 bit, programmable I/O, e.g. for modems, centronics-adaptors)
RF TV-out
7 pin round-DIN power supply-conn. (9V)

Miscellaneous
This is also a 'Model-I' version, but (compared to my C64 ASSY 250407) with a slightly different and newer board layout ('C64 version B'). According to the serial number and packaging, it was manufactured in the United Kingdom. Interesting in that context is that Commodore seems to have used different plastic for machines produced in the U.K. and Western-Germany (where my ASSY 250407 machine was produced) - the color seems to be slightly different

Successors to this best-selling machine were some 'breadbins' with improved boards (such as the 'version B2'-board), the C64C (introduced together with GEOS in 1986, which was cheaper in production and had a better-produced chipset), and the C64G (introduced to the german market in 1987 and appeared in 1989 in the U.S.), which was the last of the successful C64 series (except for the C64GS, the game system, which wasn't successful at all)

'Maniac Mansion' screenshot (6 KBytes) 'Multiplan' screenshot (6 KBytes)

Commodore 64 applications: on the left, Lucasfilm's fantastic 'Maniac Mansion', which was first presented on Summer CES 1987, and probably invented the genre of point'n'click adventures. Still looking for the chainsaw fuel, eh? Forget it, it's in the sequel. On the right, Microsoft's 'Multiplan 1.06' (1983), an early spreadsheet application and Excel predecessor (which was very popular, btw, especially on the IBM PC)

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Sothius' Home - Museum - Commodore - Commodore 64 (ASSY 250425) - additional pictures

Name	Commodore 64 aka 'C64-I', 'breadbin', 'bullnose'
Codenames	'VIC-30' (while in development)
Made by	Commodore Business Machines (CBM)
Released	1984 this particular machine was produced in 1985, as indicated on its chips the first version C64s (ASSY 326106/ ASSY 326298-01) appeared in January 1982
Serial-No.	U.K. B 2157824 Box also says MADE IN UK
Board-info	P/N 251470-01 REV.B ASSY NO. 250425 (C)1984 COMMODORE INTL COMMODORE 64 ASSY-NO. 250425 in this ASSY 250425 ('C64 version B') board's design, locations for some of the chips such as SID, color SRAM and PLA, have changed. Also, some TTL (near VIC-II) has been replaced by a MOS 8701 clock generator for cost-reduction ('improved system clock circuit design')
CPU	MOS 6510 6502 code-compatible but with 8 bit bi-directional I/O port and 256 bytes SRAM integrated produced in NMOS-process there are also machines of that board revision making use of MOS 8500-CPUs, implying that MOS started HMOS-2 production that year (1985), shortly before becoming CSG (Commodore Semiconductor Group)
Speed	985.248 KHz (PAL)/ 1.0227 MHz (NTSC)
RAM	64 KBytes: 8 pcs. Motorola MCM6665BP20 (64Kx1) additional Toshiba TMM314APL-3 (1Kx4 SRAM) for storing screen color data ('color RAM') up to 16 KBytes can be addressed as video-RAM by VIC-II expandable to 576 KB/ bankswitched (CBM 1750 RAM-expansion)
ROM/ Native OS	C901226-01 Commodore BASIC V2 (8 KBytes) C901227-03 CBM C64 KERNAL Revision 3 (8 KBytes) C901225-01 character generator ROM (4 KBytes) In this early C64 board-layout, BASIC and KERNAL were stored in two separate ROMs
Keyboard/ Layout	66 keys/ US (QWERTY)
Graphics	MOS 6569 'VIC-II' ('Video Interface Controller') MOS 8701 clock generator Max.Resolution: 320x200 pixels ('high-res') 40x25 attribute cells, each 8x8 pixel in size 2 colors per cell (background, foreground) Max.Colors: 16 ('multi-color' @ 160x200 pixels) 40x25 attribute cells, each 4x8 pixel in size 4 colors per cell (3 foreground + background) most common mode for games with tricks (such as combining two multi-color modes with interlace, or forcing BAD SCAN LINE at each raster line), it is possible to use up to 16 colors per attribute cell, or to increase the palette to 128 colors. However, since these modes all have major drawbacks (such as interlace flicker, extensive CPU- and VIC-cycle usage), they're mostly used for demos furthermore, VIC-II can create up to 256 movable display objects ('sprites'), 8 per line, and max. 21x24 pixels each Text: 40x25 characters with graphical charset this is a PAL-B version; the NTSC-M version of VIC-II was the 6567. Additionally, there were 6572 (for PAL-N) and 6573 (PAL-M)
Sound	MOS 6581 'SID' ('Sound Interface Device') 3 independant voices, each with 9 octave range (0.1Hz-4KHz in 0.059Hz steps) 4 waveforms (sawtooth, triangle, variable pulse & noise) programmable ADSR (attack, delay, sustain, release) envelope generator programmable filter, independantly selectable for each voice (low pass, high pass, Band pass, notch outputs) master volume control
Media	standard Audio-cassettes (via CBM VC-1530 'Datasette') 5.25" disks, 170 KBytes/ disk (serial drives; CBM VC-1540, CBM 1541, CBM 1570 and so on) later: other CBM-drives via IEE488-interface later: 3.5" disks (CBM 1581), 800 KBytes/disk later still: harddisks up to 30 MBytes
Input/ Output	2x MOS 6526 'CIA' ('Complex Interface Adaptor') MOS 906114-01 'PLA' ('Programmable Logic Array') 2x 9 pin joystick/ mouse/ paddles/ lightpen 44 pin female edge conn. cartridge interface 8 pin DIN-41524 audio/video (earlier versions had 5 pin video) 6 pin round-DIN CBM serial IEC-bus (printer or up to five diskdrives) 12 pin male edge conn. CBM cassetteport 24 pin male edge conn. 'user-port' (8 bit, programmable I/O, e.g. for modems, centronics-adaptors) RF TV-out 7 pin round-DIN power supply-conn. (9V)
Miscellaneous	This is also a 'Model-I' version, but (compared to my C64 ASSY 250407) with a slightly different and newer board layout ('C64 version B'). According to the serial number and packaging, it was manufactured in the United Kingdom. Interesting in that context is that Commodore seems to have used different plastic for machines produced in the U.K. and Western-Germany (where my ASSY 250407 machine was produced) - the color seems to be slightly different Successors to this best-selling machine were some 'breadbins' with improved boards (such as the 'version B2'-board), the C64C (introduced together with GEOS in 1986, which was cheaper in production and had a better-produced chipset), and the C64G (introduced to the german market in 1987 and appeared in 1989 in the U.S.), which was the last of the successful C64 series (except for the C64GS, the game system, which wasn't successful at all)


Commodore 64 applications: on the left, Lucasfilm's fantastic 'Maniac Mansion', which was first presented on Summer CES 1987, and probably invented the genre of point'n'click adventures. Still looking for the chainsaw fuel, eh? Forget it, it's in the sequel. On the right, Microsoft's 'Multiplan 1.06' (1983), an early spreadsheet application and Excel predecessor (which was very popular, btw, especially on the IBM PC)