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SGI Onyx General Maintenance

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SGI Onyx deskside I-O panels (RCS-RI)
Rear panels of a deskside Onyx: the RealityEngine2 video panel above the IO4 panel (Retro-Computing Society of Rhode Island, CC BY-SA 3.0)

Routine care, opening and handling for the SGI Onyx, from SGI's deskside and rackmount owner's guides, its illustrated parts list and the iFixit teardown of a deskside InfiniteReality machine, with owners' advice from the IRIXNet forum.[1][2] SGI's guides say the chassis has no user-serviceable parts and leave internal work to trained staff; the procedures below are for owners of machines that are now around 30 years old.[3] The parts that need attention are the offline switcher (OLS) power supply, the DC-DC converters, the blower, the two clock and NVRAM chips and the drives. For fault-finding see SGI Onyx Troubleshooting Guide.

Safety

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  • The OLS that powers every Onyx was the subject of an SGI safety letter in August 2000: after two to seven years its inductors could overheat enough to smoke and occasionally catch fire. SGI asked owners to check that systems are earthed, remove the plastic rear panel on deskside systems, keep combustible material at least a foot (about 30 cm) away, clean all inlet vents, screens and filters, shut the system down at once if it overheats or smells of smoke, and wait 30 minutes after shutdown before removing an OLS.[4] jan-jaap, who keeps a large SGI collection, does not leave his machines plugged in when they are not being used.[5]
  • 48 V DC is present on the backplane whenever the OLS is running, even when the system is halted or reset. The rackmount runs from 208–240 V mains.[6][7] The 48 V supply delivers up to 50 A, and the 3 V converters on the graphics power boards are rated at 60 A each.[2]
  • Weight: the deskside weighs at least 89 kg (195 lb).[8] For the rackmount, SGI's specification table gives 254 kg (560 lb) base and 363 kg (800 lb) maximum, while its installation chapter warns that a fully configured system can weigh over 1000 lb; use at least two people and keep it from tipping.[7][6]
  • Do not lay the deskside on its side.[1]

Environment and placement

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SGI's limits for the deskside are 5 to 35 °C at sea level and 20% to 80% relative humidity, non-condensing, when running.[8] The rackmount's operating range is 15 to 35 °C.[7]

Deskside air clearances (SGI Table 1-1)
Space above the top Left side Right side Front Back
More than 6 in (15 cm) 3 in (8 cm) 6 in (15 cm) 6 in (15 cm) 6 in (15 cm)
Less than 6 in (15 cm) 6 in (15 cm) 10 in (25 cm) 8 in (20 cm) 8 in (20 cm)

[9]

Sides are as seen from the front. Keep the machine out of dust, vibration and heat, and never run it with any sheet-metal panel open or removed; SGI warns that it will overheat.[9][3]

Power-up and shutdown

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SGI's order for switching on the deskside is the breaker on the rear power-in panel, then the monitors, the printer and finally the System Controller key. A graphics system can take up to 60 seconds to show anything; do not reset it in that time. Pressing a System Controller button during start-up aborts the boot arbitration messages.[10]

To switch off, shut IRIX down (System Shutdown, or /etc/halt as superuser), turn the key to Off, switch off the breaker and unplug the cord. Use the key, not the breaker, to restart a machine that has stopped responding.[10] Always take the key out of the switch before closing the front door, and do not leave it in the Manager position.[3][1]

The deskside was built for 110 V or 220–240 V. At 110 V SGI gives 16 A and 1500 W nominal; at 220–240 V, 13 A and 1900 W with RealityEngine2 or 2400 W with InfiniteReality. Adding graphics or VME boards to a 110 V machine may need a change to 220 V.[8][9] jan-jaap measured about 1500 W at 230 V from his Onyx, which he believes had one Raster Manager board fitted.[11]

Opening the deskside

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The steps below follow the iFixit teardown.[2]

  1. Remove the rear and side plastic skins: pull the bottom of each skin out, then slide it down.
  2. Open the purple front door. Its two latches release when the button is pushed in with a screwdriver; to take the door off, push it up and swing it away from the spring-loaded hinges.
  3. Remove three screws to open the hinged I/O bulkhead door, which swings down and exposes the 9U cardcage.
  4. Wear an earthed wrist strap. Pull the InfiniteReality frontplane straight off, release the SCSI and I/O cables from the IO4 by squeezing their side levers, and undo the two thumbscrews on the graphics cable at the Display Generator.
  5. Remove a board by pulling its top and bottom levers out together, then slide it out. A board is easier to remove beside an empty slot, so take out the neighbours of the MC3 (first slot) and the Display Generator (last slot) first. Store boards in shielded bags.
  6. To take off the backplane cover, remove the marked screws, loosen the bottom ones without taking them out, and remove the top screw last; it holds the cover until you are ready. Behind it are the power connections, the System Controller, the SCSI power and blower connectors and the power boards.
  7. The OLS slides out after its screws are removed; the blower slides out and up after three screws; a cover on the right side, held by four screws and a guide post, gives access to the SCSI backplane, the auxiliary fan and the OLS output connections.

The IP25 processors sit on HIMM modules connected through Cinch CIN::APSE pressure contacts; iFixit advises leaving them in place unless they must be removed.[2]

Boards and memory

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The MC3 takes 16 MB and 64 MB SIMMs, which come out by pulling straight up on the socket handle.[2] jan-jaap notes that the socket tabs on the MC3 and on the CPU board's cache SIMMs need considerable force and that he has broken some.[12] SGI recommends replacing SIMMs if ECC errors or hangs continue on a system whose MC3 boards are up to date.[13]

Never connect or disconnect cables with the system on. Plugging in the Ethernet cable live can blow a fuse on the IO4 or I/O adapter and take out the Ethernet, keyboard, mouse and powered peripheral ports.[1][14]

After any change to the boards, update the hardware inventory: at the PROM Command Monitor (option 5 of the System Maintenance menu) type update and then reset. The PROM cannot tell missing hardware from broken hardware, so it warns at every boot until this is done.[14] resetenv restores the factory PROM settings and also clears the network address, so note the IP address first.[14]

Cooling and dust

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The deskside has a 9.7-inch vaned rotor and two 5-inch fans, one for the power supply and one for the drive bays.[3] BackPlaner on the IRIXNet forum cleaned twenty years of dust and crumbling black foam off the boards of a deskside Onyx before powering it.[15] Clean the inlet vents, screens and filters, as SGI's 2000 letter asks.[4]

Clock and NVRAM chips

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Two Dallas real-time clock and NVRAM chips with built-in lithium cells hold the configuration. The one on the System Controller holds the system serial number; the one on the first IO4 holds the PROM environment variables and a backup of the system ID, so the System Controller's chip can be replaced without losing the ID.[16][12] By now the cells are almost certainly flat. jan-jaap fitted CR2032 cells to them; he could not desolder anything from the very thick IO4 board.[16] See Battery Refurbishment for general advice on cells.

Power supply and converters

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The OLS assembly is SGI part 013-0513 and the System Controller power board assembly 013-0616.[17] SGI's deskside guide lists the 303, 305 and 512T power boards for InfiniteReality machines, and the machine in the iFixit teardown has two graphics power boards, a 512T for the VME and IO4, and the System Controller board.[18][2] jan-jaap's experience is that the CPU, memory and I/O boards are too thick to desolder, and that the converter modules on them are sealed units.[5] The board test points take 2 mm plugs, which makes checking voltages on a live machine safer than probing with meter tips.[19] With the key in the Manager position, the System Controller's Voltage Status menu shows the 48 V, the 512 board's 5 V and 12 V, the 1.6 V termination supply and the VCAM's negative rails.[20][21][19] For the electrolytic capacitors see SGI Onyx Capacitor Replacement Guide.

Drives

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The drive rack has two internal SCSI channels, terminated on the backplane: SGI set channel A for single-ended and channel B for differential devices, and the drive sled board has a connector for each. Never plug a drive in with the power on.[3] jan-jaap warns that a single-ended or LVD disk on the differential channel can destroy the disk or the IO4.[16] Appendix B of the deskside guide covers cleaning the 4 mm DAT, 8 mm, quarter-inch cartridge and DLT tape drives and the CD-ROM.[22] See also Hard Drive Maintenance and Repair.

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References

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  1. ↑ 1.0 1.1 1.2 1.3 SGI, 007-1733-070, chapter 5, p. 113. Hardware do's and don'ts.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Mark, "SiliconGraphics Onyx Teardown", iFixit, January 2013, steps 1–8, 15–20, ifixit.com. Disassembly, power board and OLS ratings, HIMM modules, SIMM removal.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 SGI, 007-1733-070, chapter 2, pp. 15 and 29–35. No user-serviceable parts, key switch, SCSI drive rack channels, cooling, never running with panels removed.
  4. ↑ 4.0 4.1 SGI, Potential Hazard Regarding Off-Line Switching (OLS) Power Supply, customer letter 007-4267-001, 21 August 2000 (File:SGI Challenge and Onyx OLS power supply hazard letter (007-4267-001).pdf). The six recommended precautions.
  5. ↑ 5.0 5.1 jan-jaap, reply of 17 January 2019 in "Proactive maintainability of SGI Power Supplies, thoughts?", IRIXNet forum, forums.irixnet.org. Onyx power system, sealed converters, boards too thick to desolder, unplugging idle machines.
  6. ↑ 6.0 6.1 Silicon Graphics, POWER Onyx and Onyx Rackmount Owner's Guide, 007-1736-060, 1996, chapter 3, p. 45 (File:SGI POWER Onyx and Onyx Rackmount Owner's Guide (007-1736-060).pdf). Mains and 48 V warnings, weight over 1000 lb fully configured.
  7. ↑ 7.0 7.1 7.2 SGI, 007-1736-060, appendix A, pp. 133–134, Table A-1. Weight, voltage and temperature range.
  8. ↑ 8.0 8.1 8.2 SGI, 007-1733-070, appendix A, p. 136, Table A-1. Weight, electrical rating, power and environmental limits.
  9. ↑ 9.0 9.1 9.2 Silicon Graphics, POWER Onyx and Onyx Deskside Owner's Guide, 007-1733-070, 1996, chapter 1, pp. 3 and 14, Table 1-1 (File:SGI POWER Onyx and Onyx Deskside Owner's Guide (007-1733-070).pdf). Air clearances, operating conditions, 110 V systems needing 220 V for more boards.
  10. ↑ 10.0 10.1 SGI, 007-1733-070, chapter 3, pp. 55–56 and 78–79. Powering on, powering off and rebooting.
  11. ↑ jan-jaap, reply of 17 March 2021 in "Min/Max ONYX config for 120v?", IRIXNet forum, forums.irixnet.org. Measured power draw.
  12. ↑ 12.0 12.1 jan-jaap, replies of 10 and 11 November 2021 in "Onyx: boot is incomplete, fault is no master", IRIXNet forum, forums.irixnet.org. System ID in two Dallas chips; SIMM socket tabs.
  13. ↑ Silicon Graphics, CHALLENGE/Onyx Diagnostic Road Map, 108-7045-030, 1994, section 2.7.6, p. 2-37 (File:SGI CHALLENGE and Onyx Diagnostic Road Map (108-7045-030).pdf). SIMM failures.
  14. ↑ 14.0 14.1 14.2 SGI, 007-1733-070, appendix D, pp. 162–169. Hardware inventory, resetenv, IO4 fuse failure.
  15. ↑ BackPlaner, "SGI Onyx restoration", IRIXNet forum, 16 March 2019, forums.irixnet.org. Cleaning a VTX deskside.
  16. ↑ 16.0 16.1 16.2 jan-jaap, reply of 22 March 2019 in "SGI Onyx restoration", IRIXNet forum, forums.irixnet.org. Dallas NVRAM chips and CR2032 modification, differential SCSI channel.
  17. ↑ Silicon Graphics, CHALLENGE and Onyx Rack and Deskside Illustrated Parts List, 108-0129-002, 1995, pp. 2-11, 3-7 and 4-11 to 4-13 (File:SGI CHALLENGE and Onyx Rack and Deskside Illustrated Parts List (108-0129-002).pdf). OLS and power board part numbers.
  18. ↑ SGI, 007-1733-070, appendix E, p. 189, Table E-4. Power boards in InfiniteReality deskside systems.
  19. ↑ 19.0 19.1 jan-jaap, "Challenge/Onyx Power Subsystem troubleshooting", IRIXNet forum, 7–13 December 2021, forums.irixnet.org. What the voltage display shows; 2 mm test sockets.
  20. ↑ SGI, 108-7045-030, section 3.3.1, p. 3-14. Voltage Status menu.
  21. ↑ SGI, 108-7045-030, section 4.5.2, pp. 4-13 to 4-14. Manager position menus.
  22. ↑ SGI, 007-1733-070, appendix B, pp. 139–151. Tape drive and CD-ROM maintenance.


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