Tektronix 4014-1 troubleshooting advice

[Ian S. King]

I've worked with (and on) one, but that was 35 years ago!  It was nearly
new….

On Fri, Mar 27, 2015 at 9:54 AM, Josh Dersch <derschjo at gmail.com> wrote:

>
>
> On 3/27/15 9:05 AM, Jon Elson wrote:
>
>> On 03/27/2015 12:03 AM, Josh Dersch wrote:
>>
>>> 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?
>>
>
> 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
>
>
>> Jon
>>
>>
>


-- 
Ian S. King, MSIS, MSCS, Ph.D. Candidate
The Information School <http://ischool.uw.edu>

Archivist, Voices From the Rwanda Tribunal <http://tribunalvoices.org>
Value Sensitive Design Research Lab <http://vsdesign.org>

University of Washington

There is an old Vulcan saying: "Only Nixon could go to China."