Tektronix Webcam 070-8030-01 User Manual
Troubleshooting Procedures
6–28
1780R-Series Service Manual
Figure 6–9: +5 V supply output waveform when over voltage protection is operating
Current Limit Adjustment (A1R466)
Variable Auto Transformer:
See Equipment Required List in the Adjustment Procedures
section.
section.
Television Test Signal Genera-
tor (Optional):
tor (Optional):
Color Bars. See Adjustment Procedures.
75
W Feed-Through Termina-
tor.
See Adjustment Procedures.
75
W Coaxial Cable.
See Adjustment Procedures.
180
W 10W Resistive Load:
Use four 180
W, 5W wirewound resistors connected in series
parallel as shown in Figure 6–10.
Figure 6–10: Power supply load used when adjusting current limit (A1R466). Load
can be connected between the top end of A2L638 and ground
can be connected between the top end of A2L638 and ground
1. Verify that the 1780R-Series instrument is set to the desired nominal line
voltage. If the line voltage must be changed, set the rear-panel mains switch
to the correct setting.
to the correct setting.
2. Connect the 1780R-Series AC power cord to the variable autotransformer.
Set the mains Power switch for the autotransformer to On. Set the autotrans-
former to the voltage indicated on the 1780R-Series rear panel.
former to the voltage indicated on the 1780R-Series rear panel.
3. Optional: Connect a Color Bar signal from a Television Test Signal
Generator, through a 75
W feed-through terminator, to the 1780R-Series
CH A INPUT connector. (The instrument can be checked and/or adjusted
without the test signal applied.)
without the test signal applied.)
Equipment Required List
Procedure