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IBM 5120 Maintenance Guide: Revision history

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23 September 2026

  • curprev 03:4003:40, 23 September 2026 Josh talk contribs 13,984 bytes +228 Add machine photograph undo
  • curprev 03:2603:26, 23 September 2026 Josh talk contribs 13,756 bytes +4,926 Rebuilt against IBM's MIM SY34-0192-0 and Logic Manual SY34-0193-0 (both hosted here). Removes the false 'linear supply with series-pass regulators' and the invented rail table (including a '+24 V typical +/-5%' line and a '12-15 kV anode' figure): the 5120 has a transistor switching regulator board A2 plus a ferroresonant board A1 for the diskettes. Adds IBM's five rails and loaded/unloaded tolerances, the E1-E14 terminal map, the F2/F3/F4 fuse split that localises a fault to one supply, CB1... undo

23 May 2026

  • curprev 16:4216:42, 23 May 2026 Josh talk contribs 8,830 bytes +8,830 Deep technical pre-PC IBM page with verified sources (Bitsavers MIM/MAP, Wikipedia, IBM Archives) — honest gap disclosure where IBM did not publish per-board cap values
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