SGI IRIS 2000 Capacitor Replacement Guide
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No capacitor values have been published for the power supplies of the SGI IRIS 2000 series, and SGI's field-service material treats them as complete replaceable units. What is known about the machine's capacitors is set out below, with a way to record your own before ordering parts.
Warning: the power supplies run from the mains. Unplug the cabinet, let the input capacitors discharge and check them with a meter before touching a supply.
Power supplies
[edit | edit source]The 2400 has an LM-54 supply; a 2400 upgraded to a 2400 Turbo also has an LM-11, which can only be paralleled with an LM-54.[1] SGI's 2400 Turbo spares list has a single "Power Supply, 20 Slot", part 9430002, and its course lists the power supply among the field-replaceable units without describing its insides.[2][3] In 1993–94 Levine's only lead on the supplies was an old telephone number for LH Research, which was no longer in service.[4] No schematic or component list for either supply has been found.
Boards
[edit | edit source]- The Turbo models use the IP2 processor and IM1 memory boards, whose bulk capacitors are listed on SGI IRIS 3000 Capacitor Replacement Guide#Boards. SGI's IM1 schematic gives its two 100 µF capacitors as tantalum.[5]
- The UC4 and BP3 graphics boards, used in the 2000 series as well as the 3000, each have two polarised 40 µF capacitors on the +5 V supply at the Multibus connector, according to SGI's schematics, which give no type or voltage.[6][7][4]
- For the PM2 processor board of the non-Turbo models no schematic has been found. In bitsavers' photograph of a PM2 board the capacitors visible are small dipped parts.[8]
Recording your own parts
[edit | edit source]Photograph each board and supply and write down, for every capacitor, its designator, value, voltage, type (aluminium electrolytic or tantalum), temperature rating, size and lead spacing, and identify the series from its markings before choosing a replacement.
Checks after any work
[edit | edit source]SGI's settings for the supplies of the 68020 machines, measured at the terminal block with a normal load, are +5.00 V, +12.10 V, −12.10 V and −5.24 V on channels 1 to 4. On a 2400 Turbo with a second supply, the two must be balanced with the load board.[9] The 2000-series technical aids that change the +5 V and +12 V settings are described on SGI IRIS 2000 General Maintenance#Power supplies.
Related pages
[edit | edit source]- SGI IRIS 2000
- SGI IRIS 2000 General Maintenance
- SGI IRIS 2000 Troubleshooting Guide
- SGI IRIS 3000 Capacitor Replacement Guide
- Capacitor Failure Symptoms
References
[edit | edit source]- ↑ Silicon Graphics, IRIS Workstation Course, 68020 Based, Student Workbook part 2, lesson 5, "Power compartment component location", p. 6 (File:SGI IRIS Workstation Course 68020 Based Student Workbook Part 2.pdf).
- ↑ SGI, Student Workbook part 2, lesson 5, "2400T Spare Parts Stocking Guidelines", p. 16.
- ↑ SGI, Student Workbook part 2, lesson 5 objectives.
- ↑ 4.0 4.1 Jonathan Levine, "Silicon Graphics IRIS 2000/3000 FAQ", revisions of May 1993 to June 1994, sections 2.2 and 4.4.2, bitsavers.org/pdf/sgi/iris/IRIS_FAQ.txt.
- ↑ Silicon Graphics, IM1 PCB schematic, 5000-529 revision A, 10 June 1985, sheet 1, discrete legend (File:SGI IRIS IM1 memory board schematic (5000-529).pdf).
- ↑ Silicon Graphics, UC4 update controller schematic, 5000-508 revision A, 6 March 1985, sheet 1 (File:SGI IRIS UC4 update controller schematic (5000-508).pdf).
- ↑ Silicon Graphics, BP3 PCB schematic, 5000-500 revision B, 30 April 1986, sheet 1 (File:SGI IRIS BP3 bitplane board schematic (5000-500).pdf).
- ↑ Bitsavers, photograph of a PM2 board (assembly 5000-065) from an IRIS 1400, bitsavers.org/pdf/sgi/iris/1400/PM2.JPG (viewed 22 October 2026).
- ↑ SGI, Student Workbook part 2, lab 8.1, section 5 "Power Supply Adjustments", p. 31.
