>i'm not having any luck getting my PDP-11/70 to talk to the RA72s
hooked up to the UDA50 in it. =20
>anyone want to help me through this?  thanks!!

Do you have the UDA50 User Guide? I'm fairly sure a scan is available
at the DFWCUG web site. There should also be a UDA50 Maintenance
Guide there too. Right now I cannot get there, so I cannot give you
a pointer but you can try http://montagar.com/~patj/dec/hcps.htm
and just search.

An RA7x manual may help too, I can dig one out if necessary.

Page 2-25 of the UDA50 guide lists the LED codes. Basically
a cycling-flashing pattern on both boards means OK. Otherwise
you have a UDA50 problem.

Assuming that's OK, remember that you need an odd number of
SDI cables between controller and disk. Tyically 3 (controller
to bulkhead, bulkhead to other cab bulkhead and finally other
cab bulkhead to disk. Using just one cable should work (I did that
in a MicroVAX III system inside a BA214 cab to go from a KDA50
to an RA7x drive or two.

If all that is OK (and assuming the cables are OK) the next thing
to look at is the RA7x itself. In a MicroVAX cab or in a disk cab,
the OCP (operator control panel) is used to set the disk unit number
and bring it online. In your config I assume that you need to set the
unit number using switches and possibly do something else to persuade
it to come online. I'll go look up the details tomorrow, in the meantime
you can start by checking the above.

Good luck,

Antonio
arcarlini@iee.org