First VAX-11/730 VMS Boot! (was: Re: VAX-11/730 %BOOT-F-Unexpected Machine Check)

[Johnny Billquist]

On 2015-06-14 19:25, Mark J. Blair wrote:
>
>> On Jun 14, 2015, at 10:01, tony duell <ard at p850ug1.demon.co.uk> wrote:
>>
>> If the connector on the DELUA board is a normal Berg-type header (and I think it is) then maybe you could
>> use a piece of (twist-n-flat?) ribbon cable to make an extension that could be routed through the cable
>> pan arrangement and then connected to the original DELUA cable back in the rack cabinet.
>
> That might be a good approach. The DELUA end of the cable has a Berg connector, and the other end has the typical 15-pin D-sub AUI connector with a slide latch. I'll look up the cable wiring to see if signals that would best be twisted pairs are conveniently placed on adjacent odd/even pins, such that twisted pair ribbon cable would work well electrically.
>
> Or maybe I can use the round cable that I already have, with P-shaped cable clamps screwed down using the screws at one end of the flat cable clamps. There may not be enough clearance in the tray for that.

What happened to the original cable and distribution panel?
As a warning - the original distribution panel have a fuse for the 
15-pin Dsub, to avoid excessive power use on the connector. If you go 
directly from the board to a transciever, you might run the risk of 
damaging the DELUA itself if something goes wrong.

Put another way. The design is to have an internal cable from the DELUA 
to a distribution panel at the back of the machine. There you have the 
15 pin AUI connector, which have a fuse. You then had an external AUI 
cable from there to your transciever, which traditionally sat on a thick 
coax. Of course, later on, you started having thin ethernet. Still AUI 
cable and transciever, though. Eventually twisted pair showed up. But 
you had transcievers for that as well. And if you have room behind the 
machine, you could connect the thin ethernet or twisted pair 
transscievers directly to the distribution panel connector, so no actual 
external cable.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol