Tektronix 4054/4054A Calibration Graticule

[nikola-wan]

After posting my latest MONOPOLY game video, I wanted to try to straighten out the board - as it had significant pincushion on all four corners of the board:



The Tektronix 4054/4054A Technical Data service manual has a description of the Geometry and Focus Correction circuitry (which is located on the Deflection Amplifier board) and Figure 12-5 shows display Pincushion Effects.



Note: the Long Axis deflection amplifier covers the X axis geometry settings of LA GEOM and LA GAIN, while the SA GEOM and SA GAIN adjust the Y axis.

The two pages in that same service manual details how to make these adjustments on the Deflection Amplifier board:



Figure 5-7 shows the locations of the Deflection Amplifier adjustment potentiometers:



The Deflection Amplifier adjustments start with "Install the calibration graticule"!

I don't know anyone that has the 4054/4054A calibration graticule shown in the Parts and Schematics manual.

So I set out to design a calibration graticule - here is the illustration in the manual:





You have to remove the 4054 plastic bezel (after removing the top cover of the enclosure) and press the graticule against the CRT.

I wanted to create a 4054 calibration graticule - but I needed to know the nominal display X and Y size and didn't find it in any of the 4050 manuals.

Today I looked in the Tektronix 4014/4015 Service Manual (bitsavers.org) since the 4014 was introduced at the same time as the 4054 in 1979 and both had 19-inch DVST CRTs and found Figure 2-1 had this information on the Display Writing area:



I used the 14.3" X measurement for the width and 10.7" Y measurement and made a graticule pattern using virtual-graph-paper.com online tool:


This pattern barely fits on an 8.5x11" transparency sheet in my HP Laserjet color printer. You print this half pattern twice and turn the second print around and tape it to the right side of the first page to create a full size 14.3"x10.7" calibration sheet.

I used masking tape to place the calibration sheet on the CRT bezel - and ran my 4050 Calibration program from my Flash Drive Main Menu (it automatically determines whether you have a 4051, 4052 or 4054 and runs the correct calibration BASIC programs described in the service manuals - you press User Definable Keys (function keys) to select a particular program. I like the UDK1 Focus program - which draws the grid you see below from 0,0 to 130,100 - which is the full screen graphic area. I put the UDK key menu above 100 - where BASIC prints the blinking "F" for Full Screen.

My first calibration overlay was printed with black lines - but they are almost invisible against the display, so I changed them to red lines which do show up if you use a small flashlight or headlight like in my photo.

I had my iphone mounted on a tripod, so I could get the camera view of the pincushioning.

You can see several calibration issues in this photo:

1. The vertical lines on the far left and right are clearly bowed out in the middle
2. The horizontal lines at the top and bottom are bowed out in the middle
3. If you look at the calibration square to the right of the center the distance between vertical lines is almost the width of the graticule cell but the vertical lines are visibly shorter than the graticule cell - indicating the SA GAIN is too low.

I recommend you take a photo from the top of the Deflection Amplifier - so you can record the current settings of the LA & SA GAIN, GEOM, and Position pots.

Remember - this is a storage CRT - so the lines you see were drawn when you pressed UDK1.
You MUST PAGE the screen then press UDK1 again after EVERY adjustment change to see the effect of that change.

I recommend looking at one of the displayed grid corners and where it intersects the graticule and then press PAGE and UDK1 to see how your last adjustment worked.
Also - make ONE small adjustment at a time - such as slightly increase or decrease LA GEOM - which should slightly change the pincushion of the far left and far right vertical lines.

The manual indicates these adjustments interact with each other - so go slow.

I had to step away after I made too many adjustments and the screen was worse than the photo above.
When I came back and took it slow - I became more comfortable on which adjustment was needed and got this much improved pincushion and gain result:


I have attached my 4054 half-graticule SVG in a zip file that should print correctly - set margins to none and scale to default.

 

[nikola-wan]

I will also be developing a 4051/4052 calibration graticule as I need to adjust my 4052.

I did not find any viewable display area measurements in the operators or service manuals - but I did find this information in the 4012 terminal service manual which I will use to create a 4051/4052 graticule. In the text on page 2-5 it mentions approx 0.0077 inches per point spacing for the 0-1023 X and 0-779 Y axes. Dividing 1023 by 8" results in 0.0078



Here is my scaled 4051/4052 Calibration graticule - print on transparency sheet and rotate and center over your 4051 or 4052 and use masking tape to hold it to the bezel:




I put a Pincushion program in the Flash Drive Calibrate directory, but you would need to access it directly. Use the Main Menu File Browser to access the Calibrate directory and then list the files to see the file number of the Pincushion program (should be file 5). Then type FIND@5: OLD@5: RUN to execute that program to get a grid that should match the graticule!

4051-4052 Graticule SVG file attached in zip

 

[nikola-wan]

I just updated the Pincushion test program to match the graticule.

Here is the 405x Emulator screenshot:



And I have attached a zip of the Pincushion test program.

I see that my program draws the squares at the limit of the 0-1023 by 0-779 display but my calibration graticule has cropped the outer squares and the outer line is at the display limit.

No big deal - you don't have to get all the lines aligned, you will be adjusting the center position of the Pincushion image, the X and Y size and setting the GEOM adjustment pots to get as rectangular of a image as you can.

My 4052 broke (something inside popped and display went dead) - so I'll have to repair it before I can work on the pincushion calibration.

I will also update my Flash Drive image to include my changes to the Pincushion test program and see if I can add it to the Calibrate programs as a UDK selection.
I will also make sure the Flash Drive image includes my latest MONOPOLY fixes

 

[nikola-wan]

Here is my MONOPOLY photo from my 4054A after pincushion correction:

 

[nikola-wan]

I just updated my Tektronix 4050 Pincushion program.

I need to recalibrate the pincushion and X/Y size on my 4054A before I record a video of my Battlestar Galactica 1978 Demo program.

I found the 4050 Operators Manual version -01 from March 1980 Appendix B-2 lists the 4051/4052 and 4054 display "Quality Display Area"

4051/4052 11-inch DVST provides a 7.48 inch x 5.51 inch
(19.00cm x 14.00cm)
rectangle with its center with 0.25 inches of the
CRT faceplate center
4054 19-inch DVST provides a 14.00 inch x 10.50 inch
(35.56 cm x 26.67 cm)
rectangle with its center within 0.25 inches of the
CRT faceplate center.




I checked my printed graticule and it appears to be 0.25 inches higher and more than 0.25 inches wider than the quality area dimensions above.

I decided to rework my pincushion adjustment program instead of working with the printed graticule.

My program auto-detects whether you have a 4051, 4052 or 4054 and prints the Quality Area dimensions Width and Height above the pincushion graphic.
The Quality Area is the full window of graphics and text: X=0 to 130, Y=0,100.
Run this program and use a measuring tape or very flexible ruler to measure the width and adjust the setting to match the Quality Area for your 4050 computer.
Then adjust the height, and then center on the dot in the middle square on the pincushion graphic.
Now when viewing the display with the pincushion image - adjust the corners with the pincushion adjustment pots.
Here is my program:

100 REM generate 4050 screen graticule for pincushion correction
110 INIT
120 PAGE
130 MOVE 0,100
140 M0=INT(10*RND(0))
150 REM 1=4051, 7=4052 OR 4052A, 8=4054 OR 4054A, 5=4054 OR 54A /W OPT30
160 IF M0<>1 THEN 190
170 M$="4051"
180 GO TO 250
190 IF M0<>7 THEN 220
200 M$="4052 or 4052A"
210 GO TO 250
220 M$="4054 or 4054A"
230 PRINT "  Pincushion Graticule: -19in CRT ";M$;"  W=14.0in H=10.5in"
240 GO TO 260
250 PRINT "  Pincushion Graticule: -11in CRT ";M$;"  W=7.5in  H=5.5in"
260 FOR X=-1.5 TO 128.5 STEP 130/8
270 FOR Y=-1.5 TO 98.5 STEP 100/6
280 MOVE X,Y
290 DRAW X+3,Y
300 DRAW X+3,Y+3
310 DRAW X,Y+3
320 DRAW X,Y
330 NEXT Y
340 NEXT X
350 FOR Y=0 TO 100 STEP 100/6
360 FOR X=1.5 TO 128.5 STEP 130/8
370 MOVE X,Y
380 DRAW X+12.875,Y
390 NEXT X
400 NEXT Y
410 FOR Y=0 TO 100 STEP 100/6
420 FOR X=0 TO 130 STEP 130/8
430 MOVE X,Y
440 DRAW X,Y
450 MOVE X,Y+1.5
460 DRAW X,Y+100/6-1.5
470 NEXT X
480 NEXT Y
490 MOVE 0,100
500 END

and I attached the three different pincushion screenshots.

4051 detected


4052 or 4052A detected


4054 or 4054A detected