Tektronix Terminal 4012

From: Jim Davis <jpdavis_at_gorge.net>
Date: Thu Jan 4 22:35:25 2001

I have a 4012 service manual, but it's so buried that I don't know if I can
located it. I'm going home next weekend, I'll take a look, if no one else
has one available and posts as such here.
Jim Davis.

Tony Duell wrote:
>
> >
> > On Wed, Jan 03, 2001 at 11:44:57PM +0000, Tony Duell did utter:
> > > >
> > > IIRC, most Tektronix storage-tube terminals display a flashing cursor
> > > (may be rather dim) in the top left corner after power-up. Are you
> > > getting that?
> >
> > Nope... the screen brightens - with a fuzzy circle in the center...
> > eventually he whole screen is bright. Nothing I've ever done yet has
> > affected this.
>
> SOunds like the flood guns (part of the storage system) are working, at
> least partially, but the writing gun might not be. Or at least might not
> be turned on by the control electronics.
>
> Alas I don't have the 4012 service manual, only the 4014 one. These
> storage CRTs can be a little difficult to work on unless you're used to
> them as well..
>
> >
> > > Also, isn't there a LOCAL switch or similar? If there is, then the
> > > keyboard is connected to the display section (and the RS232 port isn't
> > > used) in LOCAL mode. So anything you type shoudl appear on the screen.
> >
> > Yup, there is a [Local|Line] toggle on teh front, next to a power light
> > which doesn't appear to work, two LED's I've never seen light up, and three
>
> I wonder if the power lamp is burnt out, or if there's a PSU fault.
>
> > more toggles (simply called 1, 2, 3)
> >
> > > What baud rate, etc, are you usimg, and do you know that the terminal is
> > > set for the same parameters?
> >
> > There are a couple of nice big chunky knobs on teh back to set the transmit
> > and recieve baud rate (yes, independantly!) from 110 up to 9600. Also a
>
> OK...
>
> > third knob with duplex settings. I have working null modem cables... but
> > no luck.
> >
> > There are three further adjusetments knobs on the terminal. Two on teh
> > front, one vertial and one horizontal (and labelled as such with arrows) - I
>
> Those IIRC are a bit like a mouse -- you can read the positions over the
> serial line. And thus use them as a pointing device.
>
> > assume these are crude focus or alignment adjustments. There is also a small
> > dial on the side - I assume it might be brightness? In any case, none of
>
> Probably brightness of the writing gun.
>
> My next test would be to check the voltages on the logic boards -- at
> least ensure that the +5V line and the +/-12V lines (for the RS232
> drivers) are there. And then you need to find somebody with a service
> manual and see what the wiriting gun is doing.
>
> -tony
Received on Thu Jan 04 2001 - 22:35:25 GMT