Troubleshooting The Main Board; Table 6-11: Troubleshooting The Main Board - Tektronix TDS2022C Technical Reference

Troubleshooting the Main
Board

Table 6-11: Troubleshooting the Main board

Supply Voltage range
35 V 30 V to 40 V
DC
to +3.3 V on the Main board.
+6 V 5.5 V to 6.5 V
+3.3 V 3.0 V to 3.6 V. Requires minimum load to
maintain regulation.
-4 V -5.0 V to -3.5 V
Line -2 V to 6 V open circuit.
trigger
±1 diode drop when attached to the Main
board.
1
With 3 W minimum load; still functions with no load.
Running Diagnostics
Troubleshooting Input
Connections
TDS2000C Series Oscilloscope Service Manual
To troubleshoot the Main board (acquisition module), follow these steps:
1. Remove the rear case. (See page 6-10, Rear Case.)
2. Use the test oscilloscope to measure the voltages from the power supply
module at J101 on the Main board module. The following table lists the
voltages you should expect to see.
1
floating. Pin 2 connected
DC
3. If all of the voltages are present, the Main board is probably defective.
Replace it.
The oscilloscope runs an extensive self-diagnostic routine at every power-on.
Running the diagnostics from the Service menu will provide no additional
information and therefore is not needed. The menu selections are only used during
manufacturing of the oscilloscope.
Follow these steps to troubleshoot the input connections only if the oscilloscope
appears to function normally in every way, but an input signal is not getting into
the oscilloscope as expected.
Maximum J101 power
current draw pins
15 mA 1
1.0 A 4
1.8 A 6, 7
0.8 A 9
1 mA 11
Maintenance
J101 return Derived
pins supplies
2 +28 V LCD
3, 5, 8, 10 +5 V
3, 5, 8, 10 3.3 V, +2.5 V
3, 5, 8, 10 -2.5 V
3, 5, 8, 10 Line trigger
6–37