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MicroVAX I (One) disk controller problem


Experienced Member
Apr 26, 2012
Some weeks ago my MicroVAX I disk controller died together with the disk.
I guess they got used to each other so much that they passed away collectively ...

I used a Webster SRQD11-B/02 MFM controller and an ST-251 formatted as an RD52 (the SRQD-11 allows to mimic almost arbitrary disk types).

I have no replacement SRQD11, but an RDQX2 and an RQDX3.

The RQDX2 works well with my RX50 floppy drive, but I have no compatible RD51/RD52 disk.

The RQDX3 refuses to cooperate with the MicroVAX I (don't know who's fault it is).
Trying to boot the MicroVAX I diagnostics or VMS Standalone Backup from RX50s fails / hangs.

DEC said in Micronote #43:

"There are no diagnostics that are available for the RQDX3 on a MicroVAX I that is the only reason that the RQDX3 is not supportted on a MicroVAX I."

Maybe that is not true for a MicroVAX I with an older Microcode revision?
My MicroVAX I has Microcode Rev. 5 / Hardware Rev. 1

Anyone out there still running a MicroVAX I for fun or remembering troubles of that kind?

Any hints / help welcome! (Especially donations of RD51 or RD52 disks ;-))

I'd really like to have my MicroVAX I running (rather: slow pacing) again!