RL02 Question

[Bill Degnan]

On Sat, Mar 31, 2018 at 11:04 AM, Noel Chiappa via cctalk <
cctalk at classiccmp.org> wrote:

>     > From: Aaron Jackson
>
>     > I have tried three controllers, two r/w modules and two servo
>     > controllers. I'm beginning to think the drive is fine and there is a
>     > problem with the RLV21 controller.
>
> Err, think you mean RLV12 QBUS controller board, right?
>
> Anyway, you've already tried ("three controllers") swapping that out?
>
> If you have, perhaps there's a problem with a cable and/or the terminator?
>
>
> However, at this point, sub-system swapping is probably not going to be the
> best way to make progress. I think you're going to have to actually debug
> the
> problem; i.e. dive in and work out what's happening wrong, and why, and
> trace
> it back to the origin.
>
> <snip>


I remember spending a great deal of time on my RL02 problem until I finally
figured out the problem source was the backplane.  I have a UNIBUS system
and I had a miswired DD11C.  I took a DD11B and removed the NPG jumper in
slot 2 as an experiment.  It caused my RL02 to be functional, exposing the
DD11C as the issue.

I know that this will not help you directly, but given you have (probably)
one working RL controller of the three I'd test the QBUS itself, power
etc.  Perhaps this was already discussed I am just catching up to this
thread.  I also assume this RL02 has been proven to work somewhere else
with same cables.  If not I'd try that experiment too.

Bill