Agilent Technologies E4406A VSA Series Service Manual page 38

Troubleshooting
Power Supply Check
NOTE
To further isolate the failure in the four remaining "minimum
assemblies", measure the resistance (with the power turned off) from
the power supply test points on the digital IF extender board to ACOM
on the extender board. Make the measurements with the digital IF
board removed from the extender board.
Refer to
Check for shorts (zero Ω) or very low resistance (approx. 1 Ω). If a short
or low resistance is measured, pull the remaining boards from the
instrument in the following order, and recheck the shorted test point
after each board is pulled. Note that the resistance will be different
from the table, but you should be able to tell if the shorted condition has
changed. First pull the A14 fan control board, followed by the A22 CPU
assembly, and finally the A6 power supply.
If All Voltage Supplies Are Good
If all of the supplies have measured within tolerances, and the
instrument still appears dead, refer to
Assembly" on page 54
38
Figure 1-6.
Measurement Supply
Location
A +5.2 VDC
−5.2 VDC
B
C +15 VDC
−15 VDC
D
E +9 VDC
F +32 VDC
Approximate Resistance
(Ω)
41
47
366
141
78
939
"Verifying the A22 CPU
and troubleshoot the A22 CPU assembly.
Chapter 1