Surprising Hack: Use a Commodore VIC20 to fix Commodore PET

Описание: Using an older version of the Commodore VIC20 computer to fix a Commodore PET computer? Yes!! There are several chips that are used in both computers. Let's have a look at them.

MOS 6522 VIA (Versatile Interface Adapter) - I\O control like keyboard and ports. The MOS Technology 6522 chip was used in the Commodore PET for peripheral I/O, The 6522 was used for interfacing with the keyboard, cassette tape, and other peripherals The 6522 was also used in the Commodore VIC-20 for peripheral I/O. The VIC-20 has two 6522 chips, one of which is used for the keyboard matrix and the other for joysticks, various ports, etc.

2114 - RAM
The first version of the Commodore PET 2001-8 used MPS6540 ROM chips and MPS6550 RAM chips. Later versions substituted 2316B ROM chips in place of the 6540’s and/or 2114 RAMs in place of the 6550s

MOS 6502 - CPU (Central Processing Unit) executed at 1Mhz

Can also get the 6502 and 6522s from a Commodore 1541 floppy drive *

Here are PET assemblies that use the 2114 RAM chips for the video RAM.

Dynamic PET
Assembly #8032029 2114 is used for video RAM.

Dynamic PET 80 Column that uses 2114 RAM for video RAM
Assembly #8032030-01 80 Column Dynamic PET 32K,
Assembly #8032030-02 80 Column Dynamic PET 16k,
Assembly #8032030-03 80 Column Dynamic PET 16k,
Assembly #8032030-04 80 Column Dynamic PET 16k,
Assembly #8032030-05 80 Column Dynamic PET 16k,
Assembly #8032030-06 80 Column Dynamic PET 16k,
Assembly #8032087

Universal Dynamic PET that uses 2114 RAM for video RAM
Assembly #8032090-01 8032-60Hz PET 32K,
Assembly #8032090-02 8032-50Hz PET 32K,
Assembly #8032090-03 4032-60Hz PET 32K,
Assembly #8032090-04 4032-50Hz PET 32K,
Assembly #8032090-05 4016-60Hz PET 16K,
Assembly #8032090-06 4016-50Hz PET 16K,

2114 static RAM is always used for video RAM on all PETs, except the first two boards from 1977 that used 6550.
2K of video RAM (4 chips) for 80 column PETs and 1K (2 chips) for all others.
The 2001-N Dynamic PET could be reconfigured with jumpers for different types of DRAM chips and different amounts of DRAM.

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Commodore PET repairs
Troubleshooting
Commodore PET parts
Commodore pet 2001-8
world of commodore