SGI Indigo General Maintenance

An Indigo CPU board out of the chassis, with a cylindrical cell wired to the board (ctvoigt, CC BY-SA 3.0 DE)

Routine care and service procedures for the SGI IRIS Indigo, R3000 and R4000 models, from SGI's IRIS Indigo Workstation Owner's Guide (007-9065-050), its 1992 brochure, the HP1 board schematic and owners' notes. SGI's guide covers changing the memory, the CPU board or CPU module, the graphics board, the power supply and the internal drives. The TechPubs Wiki describes a flat clock battery as a very common fault. Owners have also had to repair power supplies and to restore the Ethernet address after a change of CPU board.

Warning: always switch off at the back and unplug both the system and monitor power cables before removing the front cover. SGI's guide requires a wrist strap whenever the CPU board is handled.

Environment

IRIS Indigo physical and environmental figures (SGI brochure, R3000 models)

Item	Specification
Power	100–240 V AC, 47–63 Hz, 2.5–1.6 A; at 120 V, 2.3 A without monitor and 2.5 A with
Heat	1000 BTU per hour
Operating temperature	+13 to +35 °C
Non-operating temperature	−40 to +65 °C
Relative humidity	10% to 80% operating, 10% to 95% non-operating, non-condensing
Altitude	10,000 ft operating, 40,000 ft non-operating
Noise	33 dB(A) in typical operating position

SGI's guide asks for a site within 8 feet of a grounded outlet. Do not put the machine in a closet or other small enclosed space, do not block the front, side or rear vents, and do not drape anything over it. Its list of things to avoid includes:

• running the machine with the front plastic cover off, which changes the airflow;
• connecting cables other than audio, or adding hardware, while it is switched on;
• moving it while it is running or within a minute of switching off, since the hard disk may be damaged;
• laying it on its side;
• plugging it into a two-pin, ungrounded outlet through an adapter.

Opening the machine

SGI's procedure, used for memory, the CPU board and the CPU module:

1. Shut down IRIX, switch off at the power switch on the back, and disconnect the cables, including the black power cable.
2. Facing the front, press down on the two tabs on top of the plastic front cover and pull it away from the chassis.
3. Put on the wrist strap and clip it to a metal part of the chassis; SGI suggests the notch above the top drive slot.
4. Undo the thumbscrew on the front metal panel, using a screwdriver if it is tight, and tilt the panel down.
5. The left-hand board, labelled CPU, is the CPU board. Pull its two levers towards you and slide it out. Lay it on an anti-static surface with the large chips facing up.

To refit the board, line the lever labelled CPU up with CPU on the chassis, with the SIMMs facing left, and slide it in along the card guides at top and bottom. Make sure the notch in the top lever goes under the top edge of the chassis, then return the levers. Tilt the metal panel back up and tighten the thumbscrew until the panel is snug. Fit the bottom of the front cover into its guides and tilt it up until it snaps in place.

Memory

The R3000 and R4000 boards take different SIMMs, which cannot be swapped between them. Both have twelve sockets in groups A, B and C, in the lower right corner of the board with the sockets towards you. Fill each group with four SIMMs of the same capacity.

R3000 (IP12)

To fit a SIMM:

1. Hold it by the top with both hands, the side with the many small chips facing you. Do not touch the gold edge.
2. Put the edge into the socket and work it straight down, pressing across the top.
3. Press firmly until it snaps in at both ends. This can take considerable pressure.
4. Check that there is no gap between the socket and the bottom row of chips, and that the white lever cannot easily be lifted. If it lifts, the SIMM is not fully in.

To remove a SIMM, slip the notched end of SGI's plastic removal tool under the white lever on the right of the socket and pull straight up to free that end; the SIMM is tight and this can take considerable force. Then pull the other end free by hand.

R4000 family (IP20)

Insert each SIMM at 45 degrees with its notch on your left, then tilt it upright until the socket latches hug its edges; it does not click. To remove one, press the latches outwards with your thumbs, tip it about 45 degrees towards you and pull it out. See SGI Indigo R4000 for the full steps and the SIMM type.

Checking

After refitting the board, power on. If there is no picture and the amber front light blinks, one or more SIMMs are not seated properly. Once IRIX is up, check that the memory total includes the new SIMMs.

CPU module

On R4000-family boards the processor can be changed on its own; see SGI Indigo R4000 for SGI's procedure. On the R3000 board the processor is soldered, so SGI replaces the whole board.

Power supply

SGI's procedure for removing the supply:

1. Shut down, switch off at the back, and disconnect both the system power cable and the monitor power cable.
2. Remove the plastic front cover. The supply is the metal box in the upper right corner.
3. At the back, remove the Phillips screw on the back of the supply.
4. Push the supply out towards the front by pressing against its power sockets.

To fit a supply, slide it in from the front with the fan facing the back and the speaker facing you, refit the screw and reconnect the power cables. Check that it goes fully home. One owner found that a screw fitted in one of the holes on the back of a supply hit the case and stopped the supply seating fully in its connector, leaving about 2.2 V on the +12 V rail at the drives.

With the machine running, check that the supply fan, just above the power sockets at the back, is turning and moving air. SGI's guide treats a stopped fan as a failed supply. One owner who opened a supply found a lot of dust inside and blew it out. For repair work inside the supply see SGI Indigo Capacitor Replacement Guide.

Clock battery

The IP12's clock and battery: BT1 feeds the DP8572A clock U61 through CR1 and R636 (SGI HP1 schematic, sheet 16)

The battery keeps the boot environment and the time while the machine is switched off. When it is flat the machine repeats "Can't set tod clock" while booting. On the IP12 board the 3.6 V battery, BT1, feeds the DP8572A clock chip, U61, through a 1N914 diode, CR1, and a 1 kΩ resistor, R636.

• The original battery is a Tadiran TL-5186, 3.6 V. The TechPubs Wiki names the Sonnenschein SL-340 and SL-840 as replacements that fit in the same place.
• Alternatively, wire a holder for a 3 V CR2032 coin cell to the battery connections on the board and fix it to one of the GIO32 slot blanks. The TechPubs Wiki says the Indigo works with the 3 V cell. One owner reports converting the board to a CR2032.
• Note the battery's polarity before removing it.

After fitting a new battery, set the date and time. The PROM Command Monitor has no date command. One forum member suggests setting it from the installation tools (Inst) with admin date, which takes the same arguments as the IRIX date command.

Ethernet address

The Ethernet address is held in a 93C56 serial EEPROM in a socket on the backplane. An IP20 board copies the address across from the IP12's location in that chip, but refitting an IP12 afterwards erases it. The address can only be set from an IP12's PROM. Before swapping boards, note the address, and see the troubleshooting guide for setting it again.

Internal drives

The three bays take 3.5-inch SCSI drives on sleds. The front plate cannot be removed while the locking bar is fitted. To remove a drive, take off the front cover, push the green lever below the drive fully to the left and pull the drive out. A fitted drive's green lever should be fully to the right, lined up with the green line on the front of the drive; a drive that is not fully home stops the machine booting. Owners have used SCSI emulators in place of disks. One found that a SCSI2SD version 5.1 would not work in the Indigo and ordered a version 6.1; another runs a SCSI2SD v6, and another a ZuluSCSI.

Keyboard and mouse

The keyboard socket is a 6-pin mini-DIN that looks like a PS/2 socket, but the Indigo needs its own keyboard, with the mouse plugged into the keyboard. Ordinary PS/2 keyboards and mice need an adapter. Wikipedia warns that the two protocols use incompatible voltage levels, so plugging an SGI IRIS keyboard into a PS/2 port, or a PS/2 keyboard into the Indigo, can damage the keyboard, the computer or both.

Checklist for a machine out of storage

1. Look inside the power supply for dust and corroded parts before applying mains.
2. Replace the clock battery if the machine reports "Can't set tod clock".
3. Reseat the CPU board, the graphics board and the SIMMs, and check that the supply is fully home.
4. Power on and watch the front light; see SGI Indigo Troubleshooting Guide.
5. Check the Ethernet address in the PROM before installing software.

Related pages

• SGI Indigo
• SGI Indigo R4000
• SGI Indigo Troubleshooting Guide
• SGI Indigo Capacitor Replacement Guide
• SGI Indigo Documentation
• Capacitor Failure Symptoms
• Battery Explosion, Capacitor or Corrosion Damage
• Recommended Tools