Tektronix 485 User Manual

Calibration—485/R485 Service
b. Check that the LED for that channel turns off.
11. CHECK INPUT LIGHTS CH 1 and CH 2
a. Check that 50 £2 is lit when 50 £2/1 M£2 pushbutton is
out.
b. Check that 1 M£2 is lit when 50 £2/1 M£2 pushbutton
is in.
12. CHECK BEAM FINDER
a. Check that trace remains within the graticule area
with BEAM FINDER depressed.
b. Check beam finder operation under all combinations
of HORIZONTAL, CH 1 and CH 2 POSITION controls.
13. CHECK 50 £2 DEFLECTION FACTOR
ACCURACY, +2%, CH 1 and CH 2
a. Use the 50 £2 Amplitude Calibrator square wave as the
signal source. Use 6 division display except at 0.5 V/div and
above, where 2 V signal must be used.
b. Adjust GAIN for zero error in 20 mV/div position.
c. Check for ±2% deflection factor accuracy of all
VOLTS/DIV positions.
14. CHECK 1 M£2 DEFLECTION FACTOR
ACCURACY, ±2%, CH 1 and CH 2
a. Use the Standard Amplitude Calibrator square wave as
the signal source. Use 4 or 5 division display.
b. Adjust GAIN for zero error in 20 mV/div position.
c. Check for ±2% deflection factor accuracy of all
VOLTS/DIV positions.
15. CHECK COMMON MODE REJECTION, 50 £2
and 1 M£2
a. Connect the Type 191 Signal Generator to CH 1 and
CH 2 thru the 10X attenuator and dual BNC input cable
(TEKTRONIX Part No. 067 0525-00).
b. CH 1 and CH 2 inputs 50 £2, DC; VOLTS/DIV to
20 mV; VERT MODE to CH 1. Apply 8 divisions of 50 kHz
signal.
c. Set VERT MODE to ADD; CH 2 INVERTED. Push to
release CH 2 VARIABLE GAIN and adjust for minimum
deflection.
d. Set Type 191 Signal Generator to 50 MHz and check
for 0.8 div or less of vertical deflection.
e. Change generator to 50 kHz, and inputs to 1 M£2.
Add 50 £2 BNC terminations at inputs.
f. Readjust CH 2 VARIABLE GAIN for minimum
deflection.
g. Change generator to 50 MHz and check for 0.8 div or
less of vertical deflection.
h. Push CH 2 VARIABLE GAIN to CAL.
16. CHECK BANDWIDTH 50 £2 and 1 M£2, CH 1
and CH 2
a. Use 6 div of 3 MHz from the High-Frequency
Constant-Amplitude Sine-Wave Generator (TEKTRONIX
Part No. 067-0532-01) as reference.
b. Check for a minimum of 4.2 divisions of signal at
350 MHz in the 50 £2 input mode. (4.2 divisions at
300 MHz +35°C to +55°C.)
c. Select the 1 M£2 impedance; terminate the Sine-Wave
Generator into the GR 50 £2 thru-line termination.
d. Use 6 div of 3 MHz from the Sine-Wave Generator as
reference.
e. Check for a minimum of 4.2 divisions of signal at
250 MHz. (4.2 divisions at 200 MHz +35°C to +55°C.)
17. CHECK TRIGGER SENSITIVITY A and B
a. Check in AC, LF REJ, and DC with source switch in
INT, that triggering occurs on 0.3 div of 3 MHz, 0.3 div of
50 MHz and 1.5 div of 350 MHz.
5-6

Tektronix 485 Specifications

General

Brand	Tektronix
Model	485
Category	Test Equipment
Language	English