Schematic 320026 (Sheet 3 of 3, Board 320008)
Sheet 3 of Schematic 320026 is the video logic of Commodore's main logic schematic for the static Commodore PET 2001 board assembly 320008, the version with 6540 ROMs and 6550 RAM. The title block reads "PET Computer Main Logic, Video Logic, pertaining to board assembly #320008", Commodore Business Machines, Inc., Palo Alto, California. The image here is a separate monochrome scan of the sheet (5,096 × 3,296 pixels) from the PET 2001 schematics directory at zimmers.net.[1] The same sheet is page 3 of the colour PDF at Schematic 320026 (Complete, Board 320008), which also has sheet 1.
What the sheet shows
[edit | edit source]The sheet has the 8 MHz crystal Y1 and the video timing counters, the 6540 character generator at A2 feeding a 74LS165 shift register at B2, the two 6550 screen RAMs at C3 and C4 with their 74LS157 address multiplexers, and connector J7, which takes video, horizontal drive and vertical drive to the display board. The display board itself is drawn on Video Board Schematic.
Commodore's note on the sheet reads: "All locations are same on all boards; only the specific components will differ on boards numbered 320132, 320081, 320137, 320008. The identifying board number is in upper left corner." A position read here applies to all four static boards; the full list of boards and their fitted parts is on Schematic 320026 (Complete, Board 320008).
The drawing has no parts list. Commodore part numbers are in System Board Parts List (1 of 3) and 2001 Main Logic Assembly.
Related pages
[edit | edit source]- Commodore PET 2001
- Commodore PET 2001 Service Documentation
- Commodore PET 2001 Capacitor Replacement Guide
- Schematic 320026 (Sheet 2 of 3, Board 320008), the other board-specific sheet of this set
- Schematic 320130 (Sheet 1 of 3, Static PET), sheet 1, common to all four boards
Download: 320008-3.gif