Verifying The A9 2Nd Lo/ Fan Control Board; If The Fans Are Not Operating - Agilent Technologies PSA Series Service Manual

Verifying the A9 2nd LO/ Fan Control Board

If the Fans Are Not Operating

The power supply may be in thermal shutdown if the instrument has
CAUTION
been operating without the fans running. Allow the instrument to cool
down before troubleshooting.
If all three fans are not operating, suspect a power supply problem or a
defective fan control circuit on the A9 2nd LO/Fan Control assembly.
Refer to
the individual supplies. If the supplies are within specifications, the
most probable cause is a defective A9 board. Refer to
assembly replacement procedures.
If only one or two fans are not functioning, and the power supplies are
within specifications, suspect the A9 assembly or a defective fan.
1. Remove the front frame from the instrument. Refer to
2. Refer to
Figure 5-2 Fan Voltages
Chapter 5
"A5 Power Supply Assembly Description" on page 153
removal procedures.
Figure 5-2. Measure all of the fan voltages at J3, J4, and J5
on the motherboard.
Troubleshooting the Synthesizer Section
Verifying the A9 2nd LO/ Fan Control Board
Chapter 11
Chapter 11
to check
for
for
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