MicroVAX II - TK50 problem

Antonio Carlini a.carlini at ntlworld.com
Sat Mar 12 15:11:33 CST 2005

Witchy wrote:
> I know of the incompatibility but I'm surprised at the RQDX3
> not having the limitation - every single microPDP and qbus
> uVAX I used, installed or watched Failed Circus maintain had
> to have the disk controller last on the bus; the only
> exception to this was if you had the RQDXE extender for
> external drives. Even the machines I've got here now are built
> like that.  

RQDX1 was a mistake - the fix was the RQDX2. The RQDX3 is fine
and its position on the bus is determined by other factors,
mostly whether the cable can reach it or not :-)

> The only definition I've seen is that Q22/CD boards are the
> 'S-handle' types for the BA4xx (and some BA2xx) and non-CD
> boards need to either have jumpers removed (KDA50 springs to
> mind) or etches cut. 

Whether you need to cut stuff or not depends on what lives where.
If you have a board in the following CD slot and you do not
remove the jumper or perform the appropriate surgery, then you
will be feeding signals to that board which may upset it.

If the adjacent CD slot is empty, then I don't think you
need worry about anything.




Antonio Carlini arcarlini at iee.org

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