RT PC 6150 Model 125 - S/N 26-0000995 (wankel)
20 October 2014
- Peculiar command syntax in AIX 2.2.1
- System cabinet ejects burning material
- Power indicator illuminates, then immediately goes dark
Peculiar command syntax in AIX 2.2.1
Many commands in early AIX accept different options than their counterparts on "normal" UNIX systems. If the online manual pages are not installed, it may be difficult to determine how to proceed.
- Start X11 and aixwm on the HFT (local graphics display):
- Mount an NFS filesystem:
# mount -v nfs -n remote_host remote_path local_mount_point
- Work with magnetic tape (mt):
$ tctl [ -f tape_dev ] mt_command [ count ]
- Pause output when the screen is full (more):
$ pg file_name $ command | pg
System cabinet ejects burning material
When system is powered up after sitting for some time, there is a bang and burning material is ejected from the side of the system cabinet.
A tantalum capacitor near J26 has failed catastrophically. The silkscreen is obscured in this area so it cannot be named directly, but a visual inspection will immediately reveal which capacitor has failed. Replace it. Part is 10µF 16V tripole (three-lead). Standard two-lead tantalum capacitor may be substituted; install with positive pin to center pad, negative to either of the two outer pads.
Power indicator illuminates, then immediately goes dark
When powering on the machine, the power indicator comes on briefly, then immediately turns off. No code appears on the front panel diagnostic display. The machine gives no other sign of life.
There is a short circuit, causing the power supply to shut down.
The short was isolated to the mainboard. Two 10µF 16v tripole tantalum capacitors related to the +/- 12 VDC supply (C65 and one of a group near J26, opposite C35) have failed, but have not (yet) exploded. Replace.