Plessey/Dilog DCV54

Nigel Johnson nw.johnson at
Sun Feb 14 14:30:25 CST 2021

Has anybody got a DCV54 that they are using?

I am trying to get one working with David Gasswein's mfm board and
having no luck.

The controller is working fine with a standard floppy as an RX33, even
boots the MicroVAX from it.  But on-board diagnostics cannot format or
even recognise the mfm board as a winchester.

Just got the scope out today and found that the drive select lines are
being terminated OK on the mfm board, bit the controller is not even
dropping drive select. (Yes I have tried new cables)

Problem is I don't have anything old enough to test the mfm boards with
other than the Plessey controlelr!

I'm thinking there must be some on-board config that I am missing on the
controller. - It has never had a real mfm drive connected to it.

Any help appreciated,


Amateur Radio, the origin of the open-source concept!
Skype:  TILBURY2591 nw.johnson at

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