IBM RS/6000 3CT/39H specific notes

My 3CT is a representative of the POWER2 architecture. They once excelled in FP performance. IIRC they had an extra sqrt instruction in hardware, which might have made them particularly attractive for all simulations requiring the calculation of the Euclidean distance.
I have loaded my 3CT with AIX 4.1, because it seems to be the appropriate contemporary version. I think I might use the box for some benchmarks concerning the POWER2 CPUs. Apart from that it might have added value for other tasks because it came with CD-ROM, internal tape drive and Token Ring adapter, which is quite a lot of builtin equipment for a workstation back in the time when it was hip.

The 39H is almost identical to the 3CT, except that it was sold as a server (i.e. w/o gfx card). Parts can be exchanged between the two.
My 39H was used as a workgroup data server before, but it had rotten in some junkyard corner and was in a rather bad shape. The OS (some AIX 4.x I presume) filesystem was FUBAR ¹ and when I powered up the machine, some capacitor on the ethernet adapter exploded and literally went up in smoke!
Fortunately the box still had the keys, and not too long after I inherited it, a broken 3CT came along which I could use as an organ donor.
I used its ethernet adapter, CD-ROM drive and GXT150 gfx card to equip the 39H and installed a base AIX 4.1.5 system.

Pixx 3CT

Pixx 39H

View inside with the GXT150 card placed on top and the Ethernet adapter on the PSU.

Key Mode Secrets

Key Mode Switch

Diagnostic sequence for an 888 code

Press reset once.
    Is "102" displayed on LED?
       YES --> Software prob. press reset once for crash code,
               then again for dump code. Reboot. END
       NO  --> Continue.
    Is "103" or "105" displayed on LED?
       YES --> Hardware prob. press reset 2x for SRN code
               then again for FRU code
               press reset 8x for location code. Reboot. END

1. (f***ed up beyond all repair)

Last updated: 30-Dec-2011, M.Kraemer