Tektronix 485 User Manual

Calibration—485/R485 Service
HORIZ DISPLAY to INTEN; B TRIGGER SOURCE to B
RUNS AFTER DELAY TIME.
b. Trigger A on + SLOPE. Use DELAY TIME POSITION
control to position the intensified portion of the negative
step near center screen.
c. Switch HORIZ DISPLAY to B and position the
negative step to center screen.
d. Switch A SLOPE polarity and check that the
transition changes less than 3 divisions horizontally.
24. CHECK DELAY JITTER
a. Set A TIME/DIV to 1 ms; B trigger source to B RUNS
AFTER DELAY TIME. Set B TIME/DIV to 1 ps and
Time-Mark generator to 1 ms. Set HORIZ DISPLAY to
ALT; use A trigger LEVEL to obtain a stable display.
b. Set HORIZ DISPLAY to B. Rotate DELAY TIME
POSITION dial from 1 to 9, checking for 0.5 div of jitter or
less on B display.
SCALE ILLUM
CCW
BW LIMIT
CH 1 and CH 2
OFF
VOLTS/DIV 0.1 V
VARIABLE
CAL
INPUT
GND
POSITION
MIDR
1 Mft/50 ft
50 ft
VERT MODE
CH 1
INTTRIG
NORM
CH 2 POLARITY
+ UP
SWEEP MODE
A and B TRIGGER
NORM TRIG
COUPLING
AC
LEVEL
MIDR
SLOPE
+
A TRIGGER SOURCE
INT
B TRIGGER SOURCE B RUNS AFTER DELAY
TIME
POSITION (HORIZ) MIDR
HORIZ DISPLAY A
TRACE SEPARATION
MIDR
CAL 5 V FREQ 1 MHz
TIME/DIV
1 ms
DELAY TIME POSITION
4.00
25. CHECK INPUT PROTECTION TRIP LEVELS
for CH 1 and CH 2
a. Set Type 106 High Amplitude control to minimum;
Frequency to 1 kHz and Symmetry for 50% duty cycle. Set
CH 1 and CH 2 inputs to DC; VOLTS/DIV to 2 V; position
trace to top graticule line; input impedance to 50 ft.
b. Connect Type 106 High Amplitude to CH 1 input;
slowly increase Type 106 amplitude.
c. Check that the input disconnects (trace returns to top
graticule line) and reset lamp lights after the trace crosses
the 2.8 graticule division point and before it reaches the
4.25 division point. Return Type 106 amplitude to mini
mum and repeat for CH 2.
1. CHECK +59.4 V SUPPLY (±0.06 V)
a. Using DVM measure at +59.4 V test point on Power
Supply board.
b. If necessary adjust +59.4 (R1940).
c. INTERACTION will affect the operation of most
circuits in the 485.
2. CHECK +50 V SUPPLY (±0.05 V)
a. Measure at +50 V test point on Power Supply board.
PART 2 - 485 CALIBRATION PROCEDURE
Remove the wrap-around cover as described in the
Maintenance Section.
Connect the 485 to a power source which meets specified
voltage and frequency requirements. Press the POWER
pushbutton to turn the 485 on and allow it to warmup for
at least 20 minutes before commencing Part 2 Calibration
procedure. This instrument should be adjusted at an
ambient temperature o f +25°C f±5°C) for best overall
accuracy.
Preliminary Control Settings
CONTROL
INTENSITY CCW
B INTENSITY CCW
b. If necessary adjust +50 V (R2048).
c. INTERACTION will affect the operation of most
circuits in the 485.
3. CHECK LOW
Ground Reference
Board)
5 V +0.1 V
+15 V +0.25 V
-5 V ±0.1 V
-15 V ±0.3 V
-5.5 V ±0.25 V
+5.5 V ±0.25 V
Point on Power Supply
—9 V ±0.15 V
+9 V ±0.15 V
+25 V ±0.6 V
+120 V ±2.4 V
+180 V ±3.6 V
VOLTAGE SUPPLIES (Use
Test
5-8
REV. C, SEPT. 1974

Tektronix 485 Specifications

General

Brand	Tektronix
Model	485
Category	Test Equipment
Language	English