This page has a rough inventory of the DEC RX drive units in my collection.
Enclosures
S/N WS 21980: The power supply is marked as being a “h771-d (50HZ)” and with a voltage input of either 180-240 or 200-264 volts. As at 07/2024, this is the dual-drive RX01 in my main PDP-11/34 system. It is equipped with two RX01 drives, which currently both pass the ZRXAF0.BIC diagnostic with flying colours. I don’t recall where this enclosure came from (it didn’t come with the 11/34, which was sourced from Yarra Valley Auctions about 5 years ago). Previously only Drive 0 worked. The problem turned out to be a faulty lower PCB in the drive enclosure. I swapped it for the PCB from the ex-11/780 RX01 enclosure (S/N WS 12959) and now both drives work perfectly, so the lower PCB has a Drive 1 fault. Note I also swapped the two drives (left and right) at the same time as doing the PCB replacement.
S/N WS 12959: The power supply is marked as being a “h771-d (50HZ)” and with a voltage input of either 180-240 or 200-264 volts. When removed from storage in 07/2024, this was a complete single-drive RX01. I think it came from a VAX 11-780. It looks to be in good condition, but has no panel-mount front panel. As noted above, I swapped the lower PCB with the one from S/N WS 21980. This should be fine for this enclosure, as the fault only affects the second drive (which is not fitted). Note that I’ve also separated the drive (Calcomp Model 140D S/N 29844) from this enclosure for testing purpose (see notes below).
Individual drives
Calcomp Model 140D S/N 29844: This was separated from the single-drive enclosure S/N WS12959 in 07/2024. It looks to be in good condition, but it trips the circuit breaker on the back of a known-good RX01 enclosure after about 5-10 seconds. The spindle-drive motor does seem to have slightly higher than usual friction, but oiling and attempting to free it up had no positive effect. Note that the 100VAC rubber-insulated wires leading to the motor are significantly degraded, with the rubber falling off when disturbed. It needs to be re-wired, which will involve pulling the motor casing apart somehow.