IBM 5120 Computing System Logic Manual
The IBM 5120 Computing System Logic Manual, order number SY34-0193-0 (December 1979), is the fold-out logic diagram set for the IBM 5120. Sixteen sheets.
The sheets cover the processor, storage, diskette attachment, display and keyboard logic, the DC power distribution, and the board-to-board cable net lists. The power sheets show the supply as "5110 Power Supply Board A2" feeding +5 V, −5 V, +8.5 V, +12 V and −12 V — the 5120 reuses the IBM 5110's regulator board behind a different mains front end.
No capacitance values are printed on any sheet, and the power supply's internal circuit is not drawn. The physical layout of the supply, including the resonant capacitor C4, is in section 208 of the IBM 5120 Maintenance Information Manual instead.
Download the IBM 5120 Computing System Logic Manual here: IBM 5120 Computing System Logic Manual SY34-0193-0.pdf