Jump to content

SGI Origin 200 Capacitor Replacement Guide

From RetroTechCollection
SGI Origin 200 power supply removal
Taking out the Origin 200 power supply: slide it towards the fans to unlatch it, then lift it clear (SGI Maintenance Guide, Figure 5-15)

Capacitor notes for the SGI Origin 200. SGI's Origin200 Owner's Guide and Origin 200 and Origin 200 GIGAchannel Maintenance Guide treat the power supply, logic carrier, SCSI backplane and module system controller (MSC) as sealed replaceable units and list no components for any of them.[1][2] Neither SGI nor any owner has published a capacitor list for the Origin 200 power supply, so the values in your unit have to be read from the parts themselves.

Warning: the supply runs from mains and its input capacitors hold a dangerous charge after the cord is pulled. Unplug the module, let the supply stand, and confirm with a meter that the input capacitors have discharged before touching anything inside it.

What SGI documents about the supply

[edit | edit source]
Origin 200 power supply, per module (SGI Owner's Guide, Tables 1-1 and 1-4)
Specification Value
Rating 480 W
Input 100-120 V or 200-240 V AC, autoranging, 47-63 Hz
Inrush current 140 A maximum
Outputs +5 V, +12 V, −12 V, +3.45 V
Output power 483 W, fully configured
Power factor 0.98, corrected
Efficiency 60%

[3]

The supply feeds 5 V to the MSC whenever the rear master power switch is on, even when the system is off; the front switch and the MSC turn the other outputs on and off.[4] It powers the three fans, the SCSI backplane and 5.25-inch drives through a combined connector, the logic carrier, and the MSC through its own cable.[2] SGI also offered a redundant supply, slightly longer than the standard one, which needs MSC firmware 3.3S or later.[2] SGI's guides give the nominal outputs but no tolerances.

Signs that point to the supply

[edit | edit source]
  • Status LED blinking red during power-off: SGI's diagnosis is a power supply problem.[5]
  • Status LED blinking red during boot, or solid red, followed by shutdown: power supply or on-board voltage regulator failure. SGI replaces the supply first and the logic carrier second.[6]
  • Status LED blinking green while the system runs, on a machine with the redundant supply: one half of it has failed.[6]
  • The 1998 owner's guide describes a supply test: pressing the test button should light a green LED, and if it does not, the supply may be faulty. The guide does not show where the button is.[5]

See also Capacitor Failure Symptoms and SGI Origin 200 Troubleshooting Guide.

[edit | edit source]

The Origin 2000 module uses a different, larger supply. Owners on the IRIX Network forum have found its Nichicon electrolytics leaking, with the electrolyte eating through a gate-drive trace and destroying a switching MOSFET; the poster counted over 70 capacitors in that supply.[7] It is a different design, so none of its part values carry over to the Origin 200. See SGI Origin 2000 Capacitor Replacement Guide.

Recording your own supply

[edit | edit source]
  1. Shut the system down, turn off the master switch, unplug the cord and take the supply out (see SGI Origin 200 General Maintenance). The logic carrier has to come out first.[2]
  2. Photograph both sides of every board before desoldering anything, with designators readable.
  3. For each electrolytic, write down the designator, capacitance, voltage rating, temperature rating, maker and series, can diameter and height, lead spacing and polarity. A table like the one below keeps the record in a form others can use.
  4. Look for domed tops, leakage at the base, brown or crystalline residue on the board, and corroded traces or component legs near capacitors; the Origin 2000 failure above started with electrolyte under a capacitor.[7]
  5. Measure ESR with the part out of circuit and compare it with the maker's figure for that series.
  6. Do the same for any electrolytics on the logic carrier, SCSI backplane and MSC boards.
Record sheet
Board Designator Capacitance Voltage Temperature Series Size (D × H) Condition
Power supply, primary
Power supply, secondary

Replacing

[edit | edit source]
  • 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.
  • Keep the original can size where the board or a heat sink leaves no room for a larger one.
  • Observe polarity; mark the negative stripe on your photographs before removal.
  • Clean off any electrolyte with isopropyl alcohol and inspect the traces under magnification before fitting new parts. In the Origin 2000 supply the break in the trace was visible only under a microscope.[7]

After the repair

[edit | edit source]
  1. Refit the supply and the logic carrier with all cables, including the MSC cable.[2]
  2. Turn on the master switch. The status LED should flash red, amber and green, about half a second each, and go out: the MSC is running.[6]
  3. Connect a terminal to the AUX port and confirm the MSC> prompt, then switch on with the front switch or pwr u.[4]
  4. The LED should blink green during boot and go solid green. Check tmp and fan report n.[4]
  5. Measure the outputs against SGI's nominal +5 V, +12 V, −12 V and +3.45 V.[3]
[edit | edit source]

References

[edit | edit source]
  1. ↑ Silicon Graphics, Origin200 Owner's Guide, 007-3415-003, 1998 (File:SGI Origin200 Owner's Guide (007-3415-003).pdf).
  2. ↑ 2.0 2.1 2.2 2.3 2.4 SGI, 007-3709-002, chapter 5, pp. 75-92. Replaceable parts, logic carrier and power supply removal, supply cables, redundant supply.
  3. ↑ 3.0 3.1 SGI, 007-3415-003, pp. 7 and 21, Tables 1-1 and 1-4. Power supply rating and specifications.
  4. ↑ 4.0 4.1 4.2 SGI, 007-3415-003, pp. 79-82 and 98-107. Master and front power switches, MSC 5 V supply, AUX port and MSC commands.
  5. ↑ 5.0 5.1 SGI, 007-3415-003, pp. 192-193, Table 9-1. Status LED power supply messages, supply test button, supply described as not customer-replaceable.
  6. ↑ 6.0 6.1 6.2 Silicon Graphics, Origin 200 and Origin 200 GIGAchannel Maintenance Guide, 007-3709-002, 1999, pp. 58-59, Table 4-1 (File:SGI Origin200 and Origin200 GIGAchannel Maintenance Guide (007-3709-002).pdf). Status LED messages.
  7. ↑ 7.0 7.1 7.2 Pentium, "Onyx2/Origin 2000 Power Supplies and Capacitors - It's time, folks", IRIX Network forum, 27 December 2024, forums.irixnet.org/thread-4427.html. Owner's repair report on an Origin 2000 supply: leaking Nichicon capacitors, eaten trace, failed IRFPG40 MOSFET Q113, over 70 capacitors.


Retrieved from "https://retrotechwiki.com/index.php?title=SGI_Origin_200_Capacitor_Replacement_Guide&oldid=29160"