https://wiki.retrotechcollection.com/index.php?action=history&feed=atom&title=IBM_5120_Maintenance_Information_Manual 2026-09-27T22:40:17Z Revision history for this page on the wiki MediaWiki 1.46.0 https://wiki.retrotechcollection.com/index.php?title=IBM_5120_Maintenance_Information_Manual&diff=12148&oldid=prev 2026-09-22T00:28:50Z

<p>Create documentation page for newly hosted IBM field service manual (RTC verification drive)</p> <p><b>New page</b></p><div>The &#039;&#039;&#039;IBM 5120 Maintenance Information Manual&#039;&#039;&#039;, order number &#039;&#039;&#039;SY34-0192-0&#039;&#039;&#039; (December 1979), is IBM&#039;s field service manual for the [[IBM 5120]] Computing System, which IBM designates internally as the &#039;&#039;&#039;5110 Model X3X&#039;&#039;&#039;. 324 pages.<br /> <br /> == What it contains ==<br /> <br /> * &#039;&#039;&#039;Locations (section 2)&#039;&#039;&#039; — including &#039;&#039;&#039;207 AC Box&#039;&#039;&#039; (power on/off switch, terminal blocks TB1 and TB2, a sealed line filter module, circuit breaker CB1 and the AC line cord) and &#039;&#039;&#039;208 Power Supply&#039;&#039;&#039;, which identifies the AC box, &#039;&#039;&#039;PC Board A1&#039;&#039;&#039; with fuses F2 (+5 Vdc), F3 (&amp;minus;5 Vdc) and F4 (+24 Vdc), the &#039;&#039;&#039;resonant capacitor C4&#039;&#039;&#039;, &#039;&#039;&#039;PC Board A2&#039;&#039;&#039; carrying the AC1/AC2 inputs and the output terminals E1 to E14, transformer T1, circuit breaker CB1 and the diskette AC connectors P4 and P5.<br /> * &#039;&#039;&#039;272 Power &amp;mdash; Y1 Socket Pin Assignments&#039;&#039;&#039; — the Y1 cable to A1 board pin map and the DC rail tolerance table for loaded and unloaded conditions.<br /> * &#039;&#039;&#039;273 AC Voltage Distribution&#039;&#039;&#039;, &#039;&#039;&#039;274 DC Voltage Distribution&#039;&#039;&#039; and &#039;&#039;&#039;284 Internal Diskette DC Voltage Distribution&#039;&#039;&#039; (including load resistor RL1).<br /> * Maintenance analysis procedures, with a dedicated &#039;&#039;&#039;Power 700&#039;&#039;&#039; MAP set, plus diskette, display, keyboard and communications MAPs and the error-code and device-address summary.<br /> <br /> Section 208 is the reason this manual matters for restoration: it is the only IBM document on this wiki that names a capacitor in the 51xx family as a functional part rather than a stores item. &#039;&#039;&#039;C4 is the resonant capacitor of a ferroresonant supply&#039;&#039;&#039; &amp;mdash; an AC-rated part that sets the regulation, not a smoothing electrolytic.<br /> <br /> == What it does not contain ==<br /> <br /> No capacitance values, and no component-level parts list. The scan has &#039;&#039;&#039;no text layer&#039;&#039;&#039;, so it cannot be searched; pages must be read by eye.<br /> <br /> &lt;pdf&gt; File:IBM 5120 Maintenance Information Manual SY34-0192-0.pdf &lt;/pdf&gt;<br /> <br /> Download the IBM 5120 Maintenance Information Manual here: [[:File:IBM 5120 Maintenance Information Manual SY34-0192-0.pdf|IBM 5120 Maintenance Information Manual SY34-0192-0.pdf]]<br /> <br /> == Related pages ==<br /> <br /> * [[IBM 5120]] · [[IBM 5120 Capacitor Replacement Guide]] · [[IBM 5120 Maintenance Guide]] · [[IBM 5120 Troubleshooting Guide]]<br /> * [[IBM 5120 Computing System Logic Manual]] · [[IBM 5110 Maintenance Information Manual]]<br /> <br /> [[Category:IBM Service Manuals]]<br /> [[Category:Service Manuals]]</div>

Josh