Atari 520ST and 1040ST Computer Field Service Manual

Atari's own field service manual for the Atari 520ST, Atari 520STM, Atari 1040STF and Atari 1040STFM, part number CO26118-002 revision B (3.6), January 1987. It gives the power supply specifications for both the external linear brick and the internal switching supply, the theory of operation, the diagnostic-cartridge procedure with Atari's error-code tables, the "troubleshooting a dead unit" sequence, disassembly and assembly for both cases, the symptom checklist, the 1 May 1986 1040 STFM parts list, and the schematics and silkscreens.

Download the manual here: File:Atari 520ST and 1040ST Computer Field Service Manual.pdf