Connecting a BC80M cable to a RLV12 controller

[Ethan Dicks]

On 11/10/05, David Betz <dbetz at xlisper.mv.com> wrote:
> I finally got a drive select plug for my RL01 drive and would like to
> try connecting it to my 11/73 but I find that the cable that is
> supposed to plug into the RLV12 controller isn't keyed so it can go
> in either way. How do I tell what the correct orientation is for this
> cable?

Look at the connector - there is no enforced keying, true, but most Bergs
I've seen have a pair of sub-mm-wide grooves that parallel the connector
pins - those grooves are on the same side as the occasionally-seen keying notch.

So... looking at the connector on the controller end, I'd expect to
see a 2mm ^ 2 notch in the middle of the connector... that side (up)
would go with the grooved side of the cable.

> I'm assuming that if I plug it in backwards I'll fry the controller and/or drive.

Nope.  DEC stuff is nice and robust that way.

 The only markings on the end of the cable
> that connects to the controller are the manufacturers name "Berg" and
> the letters A and B near one end and VV and UU near the other end.
> How should this cable be inserted into the RLV12?

If you have markings on the connector, then it's much easier... I
don't have an RLV12 in front of me, but the standard blue DEC Berg PCB
connector has pin markings embossed into the face of the plastic, does
it not?  If not, then start by aligning the A-side of the connector
with the left side of the connector on the controller as you look at
it (perhaps it's marked with a pin-1 indicator, or perhaps the PCB has
a square pin)

In any case, try what looks like the right choice, and if your FAULT
light is still powered on, flip the connector and the FAULT light
should be off (when both the drive and the CPU are on).

-ethan