VAX4000 VLC diagnostics/console

Adrian Graham binarydinosaurs at
Wed Jul 14 12:32:48 CDT 2021

VT100 to the rescue, the VLC is fine talking to it so now I'm wondering why
my old faithful hardware UART in this PC I'm typing on now has let me down.

The BlueSCSI appears as 7 devices though, which is usually a termination or
ID problem so I now need to dig out an external terminator for the box
since it's never had one. The hard drive in there has been good at
providing its own TERMPWR which the BlueSCSI should too but I'll play by
the rules to test things properly.


Adrian Graham
Owner of Binary Dinosaurs, the UK's biggest private home computer
t: @binarydinosaurs    f:

On Wed, 14 Jul 2021 at 08:32, Adrian Graham <binarydinosaurs at>

> On 13 Jul 2021, at 23:20, Antonio Carlini via cctalk <
> cctalk at> wrote:
> On 13/07/2021 22:34, Douglas Taylor via cctalk wrote:
> On 7/13/2021 3:30 PM, Adrian Graham via cctalk wrote:
> Hi folks,
> Powering up with nothing attached apart from an MMJ/H8571 cable I get
> nothing on the console, I'm using PuTTY via a genuine COM1 port on a PC
> which is one level above what I used last time I powered the machine up
> (FTDI USB adapter to a laptop). Diagnostic LEDs cycle through the tests and
> end up at '1111 0011' which according to the manual is 'entering the
> console program'.
> There are 2 ways to have a console on the VAX4000/VLC.  A switch on the
> back selects either; (1) graphics console mode, or (2) terminal attached to
> the serial port.  It sounds like you have the switch set to graphics
> console mode, in that case you get nothing from the serial port.
> I can't remember where the switch is on the back, bitsavers or someone who
> remembers can help.
> Doug
> If you look from the front it's on the right hand side and marked "S3",
> between the grey reset switch and the keyboard connector. I think that S3
> needs to be UP otherwise it would expect a monitor and keyboard to be
> attached.
> The MMJ connector is on the back (but obviously Adrian has found that ...
> or he's pushed really, really hard into either the keyboard connector or
> the phone connector :-))
> Bear in mind I’m an old DEC head and have been since the early 80s ;)
> Though I HAVE seen customers get RJ11 cables jammed in MMJ ports before,
> because ’they look alike’.
> Both of you missed my sentence where I said ‘It doesn’t matter what
> position I have S3 in’, and IIRC even with S3 set to graphics you would
> still get a dead sergeant on a VT once init had completed, you just
> wouldn’t see POST.
> Anyway, I’ll hook up a VT today at some point and see if anything happens.
> Cheers
> --
> Adrian Graham
> Owner of Binary Dinosaurs, the UK's biggest private home computer
> collection?
> t: @binarydinosaurs    f:
> w:

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