I'm trying again to get my 11/750 running. It turns on, power lights
are green, machine comes up halted with the dim error light as it
should. THe problem I am having is, I get no console...I get an echo
back of the characters I type, but nothing else. Doing a BREAK command
or a Ctrl-P does nothing.
A couple of questions :
1) Do you get an _exact_ echo back, or is the system processing the
characters at all. In particular, does it add the <LF> after a <CR>
2) What, precisely, are you using as a console terminal?
Now, this does not sound similar to my problem. I
verified that all the jumpers on the backplane are in the right place,
and so are the connectors. The jumper is set to 300 baud, and that is
indeed the only setting I get a clean echo back without garbage on.
I asusme you're chaning both the VAX baud rate jumper and the buad rate
of the terminal. What happens if you set the VAX to, say, 1200 baud and
keep the terminal at 300 baud. Do you get a clean echo then?
You shouldn't, of course, but I've seen something like this once before.
It was that the ground between the computer and the terminal was open.
The whole computer logic was acting as a poor _hardware_ loopback between
TxD and RxD of the terminal. It wouldn't run very fast due to the
excessive capacitacs between terminal ground and the 'loopback'.
In fact when I had this it was even more evil. A genuine DEC terminal
worked (this was on a port of a DECserver IIRC), but a laptop wouldn't.
The reason was that the terminal's signal ground was internally tied to
mains earth, and the gorund parth was being completed that way. The
laptop, being battery-powered didn't have a connection to ground.