ocr: - - - - Issue 6, 1985 : Computer 1 commodore Model: C-64, C-16, Plus 4 TECHTOPICS SCHEMATICS FOR C-64, C-16, PLUS 4 01900 COMMOUORE BUSINESS MACHINES NC These computers have been affected by an Engineering Change Order that adds 4 diodes to the serial port. These protection diodes are not required as field upgrades. They are 1N914s and were added as a circuit improvement. The Schematic and PCB Layout for the C-64 in the Service Manual (Pages 28 and 32) include these diodes. However, the C-16 and Plus 4 Service Manuals were completed before the changes were made. The Schematic corrections are s ...
