High Voltage Supplies (8560E Only) - HP 8560E Service Manual

4. Check A6TP304 for +28 Vdc.
5. Check A6TP305 for −12.6 Vdc.
6. Check A6TP308 for +5 Vdc.
7. If the voltages measured above are correct but the power supply
8. If the voltages are low, disconnect W1 from A6J1 and measure the
9. If the voltages do not return to near their nominal range, the A6
10.If the +5 V supply is low, suspect the +5 V regulator or the feedback
11.Check output of U306A pin 1. If the feedback circuit is working
12.Check output of U302; its output should be high if the feedback
High Voltage Supplies (8560E)
1. Press
2. Connect the negative lead of a DVM to A6TP401 and positive lead to
3. Press
4. If the voltage displayed on the DVM is approximately +110 Vdc and
Ideally, the DVM should read the voltage written on the label of the
NOTE
A6A1 HV module. If necessary, perform the "High Voltage Power
Supply" adjustment in Chapter 2.
5. If the DVM does not read approximately +110 Vdc, measure the
6. If HV_SHUT_DOWN is low, suspect a bad connection along W8
7. If HV_SHUT_DOWN is correct, connect an oscilloscope to A6TP402.
Chapter 12
LEDs on the A2 controller assembly are not lit, check W1.
test point voltages again. Unless a dummy load is connected to the
A6 power supply, the voltages should return to their nominal
voltages but be unregulated.
power supply is probably at fault.
circuit. To check the feedback circuit, measure the voltage of the +5
V reference (U305 pin 6) and the ±5 V references to the voltage
regulators (U306B pin 7 and U306D pin 14).
properly, the output of U306A should be near +13 Vdc.
circuit is working properly.
to turn spectrum analyzer off, disconnect the power cord,
LINE
and remove the power supply shield.
A6TP405.
to turn spectrum analyzer on.
LINE
the rear panel CRT +110 VDC ON indicator is lit, the A6A1 HV
module is probably at fault.
voltage on A6U401 pin 10. This is the HV_SHUT_DOWN signal and
should be near +5 Vdc.
between the A6 power supply and the 17 CRT driver.
Connect the scope probe negative lead to TP401. Set the oscilloscope
Display/Power Supply Section
A6 Power Supply Assembly
645