After Tramiel left Commodore in 1984, the company
started to look for other fields to explore. In mid-1980s PCs gained
much popularity and Commodore started a large family of IBM PC clones.
Probably the first one, PC5 released ca. 1984, had single floppy disk
drive and 512kB of RAM. Next models, PC10 and 20 (1985), used the same
casing left from Commodore's graphics workstation (so in early PC10 and
some PC20-II mainboard had to be split to two boards connected by
goldpin interconnect), and PC20 was a cost-reduced version of PC10 with
single floppy drive. In 1986, PC-20 got a 20MB hard drive and was sold
as PC20-II. All of them used different ATI graphics adapters compatible
with MDA, CGA or Hercules, sometimes in one board.
The problem was that PCs manufactured by Commodore (mostly in Germany) were not much different than much cheaper Chinese and Taiwanese clones. So after releasing next versions, previous were made even more "cost-reduced" giving a mess of revisions, versions and editions. PC10 without hard disk was manufactured until 1987 when mainboard was re-designed and... sold as PC10-1 (one FDD, 512kB) and PC10-2 (2 FDDs, 640kB) leaving HDD branch to PC20-II and later types. The goal of these maneuvers was to make older PCs cheaper and, in perspective, more affordable than Asian clones. But even introducing a home-oriented small PC-1 in 1987 did not saved Comomdore's situation with PC clones.
In Europe, Commodore PCs got some small popularity in Germany where they were manufactured, but in other countries they were much more expensive than Taiwanese PC clones. Because PC was, in user's perspective, just a PC with all PC software, most customers bought cheaper Asisn PCs with the same specifications.
|Origin||USA / Germany|
|Year of unit||1986?|
|Year of introduction||1985|
|ROM||Commodore PC BIOS|
|Graphics||CGA/Monochrome (ATI Graphics Solution rev. 3)|
|System expansion bus||8-bit ISA|
|Floppy/removable media drives||2x 360kB 5.25" floppy drives|
|Hard disk:||20MB Kalok KL-320 (non-original)|
Peripherals in collection:
|Controller for hard disk|
My unit has been built for German market, but it was
probably bought by Polish customer. The monitor (Commodore 1402) is
later, and CPU probably had some other one. In 1990 hard disk upgrade
As I got it, hard disk was not working After making ribbon cable more stiff it was possible to make it running with relatively small amount of bad sectors. I've added 256kB to sockets in mainboard to have 640kB of memory.
The mainboard's ISA slots part has holes drilled in tracks, these drills were made in factory.
To quickly distinguish between German and American Commodore PCs, look at floppy disk drives - in my German unit they are operated by pushbutton, not turning lever. German PCs had BASF drives with button mechanism, while USA PCs had Alps with lever.
|Contents:||Starting, usage||Jumper settings||Links|
By hardware it is a bit different than IBM's PC, as it has PLAs and GALs, as well as RS232 and Centronics onboard, but for software it is compatible with IBM PC. It just boots DOS from floppy you give it.
After power on, BIOS starts displaying frame with information and counting memory as part of POST. Then it emits series of high-pitched sounds and tries to boot from floppy.
As of today (2016) it is a bit hard to get jumper and DIP switch settings. These settings have been compiled from similar Commodore computers documentation and tested in my unit.
In the mainboard, there is a DIP stiwch bank near
interconnection of two boards (1 - ON, 0 - OFF):
1 - Deafult OFF - ON reboots after memory test. For factory burn-in testing
2 - Default ON - OFF if 8087 is installed
3,4 - 00 - 640kB of RAM installed, 10 - 512kB of RAM installed, 01 - 256kB of RAM installed, 11 - 128kB of RAM installed
5,6 - Factory set to 0,0
7 - Default OFF - On deactivates floppy disk drives
8 - Default ON - ?
ATI Graphics solution Rev. 3 has a DIP switch bank on
its edge. Near DIP switch bank there are 3 connectors. The two-pin one
is in most ATI cards a composite video output (it should be checked
before using), while longer one is for light pen. I don't know what is
the third one for. Switch 1 is closer to the bracket. I am not certain
of these settings (deduced from SE and Rev. 2 versions), you have been
warned. The possible DIP switch meanings are:
1,2 - 10 - monochrome adapter, 01 - CGA, 00 - CGA emulation
3,4,5 - 100 - TTL RGB/monochrome monitor, 011 - Analog monochrome or composite monitor, 000 - EGA monitor
6,7,8 - Factory set to 100.
JP1 is factory set to 2-3.
Interestong files in Bo Zimmerman's site. Service manuals, diagnostic
manuals, disk images, ROM dumps...
http://dostalgie.de/downloads/pc10-20-10II-20II/PC10_II_SM_COMMODORE_EN_DE.pdf - Mainboard is the closest to this design.
http://www.europeana.eu/portal/pl/record/91658/MM_objekt_1089824.html - described as PC 10
http://gona.mactar.hu/Commodore/monitor/schematics/1402_Monitor_Service_Manual.pdf - Commodore 1402 service manual