Atec Tektronix-1502 - Manual (Page 45)

TM 9-4935-601-14-3&P
Adjustment Procedure
3. Remove the EMI shields from the top and bottom of the unit. Place the battery pack in the rear of the
1502, taking care that the polarity is correct. Connect the ac power cord to the ac outlet, at the rear of the unit,
and to a 115 Vac (230 Vac for Option 6) power source.
4. Pull the POWER switch to turn the unit on and allow 20 minutes warm-up before proceeding with the
calibration.
5. Preset the front panel controls as follows:
INTENSITY Fully cw
ZERO REF SET Fully cw
POSITION Midrange
mp/DIV 500
NOISE FILTER Out
GAIN Fully ccw
DISTANCE Dial 000
FEET/DIV (METRES/DIV) 200 (50) (FIND)
MULTIPLIER X1
FOCUS Adjust for a sharp trace
CABLE DIELECTRIC
SOLID POLY In
SOLID PTFE Out
Other Out
VAR Fully cw
6. Place the DM 501 Digital Multimeter in the TM 503 Power Module. Plug in the TM 503 to an ac power
source and pull the PWR switch on.
7. Set the DM 501 RANGE/FUNCTION control to 200 DC VOLTS. Connect the test leads to the HI and
LO INPUT terminals.
Power Supply Checks
The power supply voltages of the 1502 should be checked before any internal adjustments are made.
Power supply checks are not to be considered performance checks. The location of the test points and
adjustments are shown in Fig. 4-5. Measure the supply voltages with the DM 501.
Voltage Measurements
8. Connect the lead from the DM 501 LO terminal to TP6332 (GND, black test point) on the 1502 Power
Supply board.
9. Connect the lead from the DM 501 HI terminal to TP6256 (red test point).
10. Adjust R6358 (HV ADJ) so the voltmeter reads +25 V
±
0.25 V.
11. Move the test lead from TP6256 to TP6411 (violet test point).
12. Change the DM 501 RANGE/FUNCTION switch to 20 Vdc.
13. Adjust R6514 (+10 ADJ) so the voltmeter reads +10 V,
±
0.1 V.
14. Move the test lead from TP6411 to TP6227 (green test point) and check that the voltmeter reads +5 V
±
0.25 V.
15. Move the test lead from TP6227 to TP6218 (orange test point) and check that the voltmeter reads -5V
±
0.25 V.
16. Change the DM 501 RANGE/FUNCTION switch to 200 Vdc.
17. Move the test lead to connector P65 Pin 6 (see Fig. 4-6) and check that the voltmeter reads +100 V
(+20 V, -5 V).
18. Move the test lead to P65 Pin 7 and check that the voltmeter reads +165 V (+25 V, -5 V).
CRT Adjustments
19. Turn the 1502 upside down on the bench.
20. Attach the precision 50
Ω
cable to the CABLE output.
21. Check-for a step pulse on the crt.
22. Adjust-TD BIAS (R1692) control fully counterclockwise and adjust AVAL VOLT (R1525), LOOP GAIN
(R1543), and SNAP-OFF (R1538) until a pulse appears. This is a rough setting of these controls. Finer
adjustments will be done later.
Trace Focus and Astigmatism
23. Set the FEET/DIV (METRES/DIV) to 2 (.5) with the MULTIPLIER control to X.1.
REV D JUL 1980
4-7