RL02 Question

[Aaron Jackson]

> 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

Thanks for the tip Bill.

I have run out ideas for debugging on the drive - everything looks fine!
I have starting turning my eyes towards my RLV12 controller. A friend
has recently bought an RLV12, so I can test it with his in the near
future.

Although, studying the technical description manual, I am not seeing
that any communication, other than 4.1MHz clock, is required when
loading the heads. I have been assuming that all of this logic is
handled by the drive only.

Thanks again,
Aaron.