Tek 4051 was Re: Weekend finds! - test-drb@ccmp.vtda.org

24 Nov 1998

...
 > ROM and FFT ROM (I don't have that one). 
There are two connectors on the
...
 > top back of the 4051. I don't know what
they're for except that one has a
...
   note not to
connect the joy stick unless the machine is off, so I assume
 that's what it's for. I think the other is for a printer. 
 Guessing...

 One is for an analogue _potentiometer_ joyustick. This is like a CoCo
 joystick, not the variable resistor one on a PC. 
I have the pinout.  Interestingly, although the joystick is mentioned in
the Tek manuals, Tek hadn't heard of it when I spoke to them (this was an
engineer who had actually worked on 4050 series machines, btw).  Similarly,
the manuals don't admit the existence of the joystick fire button but you
can connect it and it does work.

The potentiometers on my PC joystick (to which I added a new connector, and
which I rewired so that you actually get at both ends of the pot) are too
high resistance at about 200k ohms each.  1k to 10k is a more suitable
value.  I keep meaning to add a buffer amplifier...

Philip.