Tektronix 551 Dual Beam Instruction Manual page 103

On instruments with S/N above 5080, some circuit changes were made
in the CRT system.
ZONTAL SENSITIVITY BALANCE control and the necessary circuitry
to provide -individual control of the cathode voltages to compensate for
slight differences in the horizontal deflection sensitivity of the two
halves of the CRT.
The HORIZONTAL SENSITIVITY BALANCE control will permit
optimum registration of the two traces. The control range is± l 1/2 mm.
Note that the edge focus and geometry are not changed by this mod­
ification.
To check the registration, insert time m arkers from a 180 TIME MARK
GENERATOR into both channels of the 551, superimposing the two
traces. If
CALIBRATION section of this manual.
1. Set the HORIZONTAL SENSITIVITY BALANCE control to mid
range.
2. Set the INTENSITY and INTENSITY BALANCE for low but equal
intensity.
3. Adjust the FOCUS and ASTIGMATISM controls for optimum
sharpness.
4. If the lower beam is shc::t, the cathode of the lower beam must
move in a positive direction so turn the HORIZ. SENS.BAL. control CCW.
If the lower beam is long, the cathode of the lower beam must move
in a negative direction so move the HORIZ. SENS. BAL. control CW.
Now the HORIZ. SENS. BAL. control should give you the last half mm
of adjustment you need to give good registration of the two traces. You
will note that the HORIZ. SENS. BAL. control moves one trace one way
and the other in the opposite direction.
There is an interaction between the INTENSITY BALANCE, HORI­
ZONTAL SENS. BAL. and focus controls. It may be necessary to repeat
the sequence of adjustment until the two traces match in timing, focus
and intensity.
TYPE 551
MOD 6402 - Tent S/N 5080
These changes consist of the addition of a HORI­
registration does not occur, adjust as shown in the
CALIBRATION PROCEDURE