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SGI Origin 3000 Capacitor Replacement Guide

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SGI Origin 3000 power bay power supply
Origin 3000 power bay supply, front and rear: power, predictive fan fail and supply fail LEDs, two fans, input and output connectors (SGI Owner's Guide, Figure 10-4)

Capacitor notes for the SGI Origin 3000 series. SGI's owner's guide reserves the power bay and its supplies for SGI's own engineers, and neither it nor the technical configuration guide gives component lists for the supplies or the bricks.[1][2] No owner has published a capacitor list for the Origin 3000 either, so the values in your system have to be read from the parts themselves.

Warning: the supplies run from 200-240 V mains and their input capacitors hold a dangerous charge after the cords are pulled. Switch off the PDU or PDS breaker, unplug the rack, let the supplies stand, and confirm with a meter that the input capacitors have discharged before touching anything inside one.

The power system

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Origin 3000 power bay (SGI Owner's Guide, chapter 10 and Table A-6)
Item Value
Supplies per bay Three to six, hot-swappable
Input per supply Single-phase 200-240 V AC
Output per supply 950 W at 48 V DC
Bay output Up to 4.4 kW continuous with six supplies; eight 48 V outputs to the bricks
Standby 12 V to each brick's L1 controller
Supply size and weight 127 × 71 × 330 mm, 4 kg

[1][3]

The power bay's power management card switches the supplies and the output ports on and off and monitors faults; it also holds a serial ID EEPROM that the bricks' L1 controllers read over the power cable.[1] Inside each brick, VRMs and DC-to-DC converters make the lower voltages from the 48 V; the C-brick has three 2.5 V, 30 A VRMs on its IP35 motherboard, and the X-brick power board has five VRMs, one DC-to-DC converter and three voltage regulators.[4][3] The D-brick has its own two supplies running directly from 220 V.[1]

Signs that point to a supply or regulator

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  • A supply's FAIL LED lit with AC present, or the green power LED off: SGI's table reads this as a supply failure.[1]
  • FAIL blinking with the power LED on: the 48 V output has reached its current limit.[1]
  • PFAIL blinking: predictive failure.[1]
  • An L1 message ATTN: x.xV low (or high) warning limit reached or fault limit reached, which names the rail that is out.[5]

See SGI Origin 3000 Troubleshooting Guide for the full tables, and Capacitor Failure Symptoms.

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Owners of the later SGI Origin 350 have traced low and missing rails to the switching regulators on its interface board, whose output capacitors are surface-mount solid aluminium or polymer types; in the one case where new output capacitors were tried, a new regulator chip was what cured the fault.[6] The older SGI Origin 2000 supply has had leaking electrolytics; see SGI Origin 2000 Capacitor Replacement Guide.[7]

Recording your own system

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  1. Power the system down from the L2 or L1 (pwr d or * power down), switch off the PDU or PDS breaker and unplug the rack.[8]
  2. Photograph both sides of every board before desoldering anything, with designators readable.
  3. For each electrolytic or polymer capacitor, write down the designator, capacitance, voltage rating, temperature rating, maker and series, size and polarity.
  4. Look for domed tops, leakage at the base, brown or crystalline residue, and corroded traces near capacitors.
  5. Measure ESR with the part out of circuit and compare it with the maker's figure for that series.
Record sheet
Unit Designator Capacitance Voltage Temperature Series Size Condition
Power bay supply, primary
Power bay supply, secondary
Power bay management card
C-brick IP35 VRMs
Other brick power board

Replacing

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  • Fit the same capacitance and at least the same voltage rating, 105 °C parts, and low-ESR series wherever the original was a low-ESR type.
  • Replace solid polymer or solid aluminium parts with the same technology, at an equal or lower ESR.
  • Keep the original size where a heat sink or neighbouring part leaves no room for a larger one.
  • Observe polarity; mark it on your photographs before removal.

After the repair

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  1. Refit the supply and fit blanking panels in any empty positions in the bay.[1]
  2. Turn on the breaker. The supply's power LED should blink while only standby is on, and stay on once the DC outputs are on; PFAIL and FAIL should stay off.[1]
  3. Power the system up and run env on each brick. Every rail should be inside its warning limits; SGI counts 10% from nominal as a warning and 20% as a fault.[9][5]
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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 SGI, 007-4240-002, chapter 10, pp. 199-210, Table 10-1. Power bay, power supplies and LEDs, power management card, VRMs and converters, D-brick supplies, blanking panels; supplies to be serviced only by SGI engineers.
  2. ↑ Silicon Graphics, SGI Origin 3000 Series Technical Configuration Owner's Guide, 007-4311-002, January 2001 (File:SGI Origin 3000 Series Technical Configuration Owner's Guide (007-4311-002).pdf).
  3. ↑ 3.0 3.1 SGI, 007-4240-002, appendix A, pp. 225-227, Tables A-4 and A-6. Power supply size and weight, X-brick power board, power bay specifications.
  4. ↑ SGI, 007-4240-002, chapter 4, p. 118. IP35 motherboard VRMs.
  5. ↑ 5.0 5.1 SGI, 007-4240-002, appendix C, p. 289, Table C-1. Voltage warning and fault messages.
  6. ↑ "Origin 350 - PCI 5V missing", IRIX Network forum, posts by aSpartan111 and weblacky, September to December 2023, forums.irixnet.org/thread-4064.html.
  7. ↑ Pentium, "Onyx2/Origin 2000 Power Supplies and Capacitors - It's time, folks", IRIX Network forum, 27 December 2024, forums.irixnet.org/thread-4427.html.
  8. ↑ Silicon Graphics, SGI Origin 3000 Series Owner's Guide, 007-4240-002, December 2001, chapter 2, pp. 49-60 (File:SGI Origin 3000 Series Owner's Guide (007-4240-002).pdf). Powering off.
  9. ↑ SGI, 007-4240-002, appendix B, pp. 239-241. env command.


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