27 Mar
2015
27 Mar
'15
9:54 a.m.
On 3/27/15 9:05 AM, Jon Elson wrote:
On 03/27/2015 12:03 AM, Josh Dersch wrote:
Yes, as I said I've been studying the service manual (on Bitsavers),
which in typical Tek fashion is extremely detailed and helpful. It
outlines the whole alignment procedure, but I figured I'd ask here first
-- since this is a nearly 40-year-old terminal I'm interested to know if
anyone on the list has dealt with similar issues and if there might be
common failure points to check out before trying to re-align the thing.
Thanks!
Josh
Hi all --
Picked up a Tektronix 4014-1 terminal. It's in pretty good shape,
nice and clean and it's in nearly-working condition except that the
storage behavior isn't quite right.
On power-up, write-through doesn't. (That is, characters don't get
stored to the tube.) Clearing the display via the RESET/PAGE key
clears a roughly elliptical region in the center of the display but
leaves the outer edges a mess. The cleared region stores characters
properly. You can see the overall effect here:
http://yahozna.dyndns.org/scratch/tek4014/clear.jpg
After a 2-3 minutes of warming up the area cleared by RESET/PAGE
increases. I haven't run the terminal long enough to see if it
eventually completely erases the screen (while the power supply
appears to be within tolerances, I still need to rebuild/reform it so
I'm not going to run it too long yet).
Let it fully warm up. My guess is the cathodes in the flood guns are
getting weak. Allowing them to fully warm up will probably help
some. Also, as others have suggested, there may be some voltage
adjustments that need to be set.
But, the final adjustment is to set some of the voltages on the guns
for optimum performance. there is a VERY critical adjustment of the
flood guns (I think that's the right term) to get the storage to be
stable as long as possible. Too much or too little flood beam causes
the stored image to either bloom or fade. Then, the erase is
performed by changing some voltage on the storage grid and pulsing the
flood guns, and secondary emission (I think) erases the charge on the
storage grid. It has been 30 years since I had to mess with a
4010/4014 series, but I THINK I still kind of remember how they work.
Have you checked bitsavers for a manual? 
Jon