Agilent Technologies 8590 Series Service Manual page 223

If the fan is not operating
The A8 power supply may be hot if the instrument has been operating
CAUTION
without the fan running. Allow the instrument to cool down before
troubleshooting.
The B1 Fan receives +12 Vdc from the A8 power supply after the power
supply receives the start-up signal, low-power-on (LPWRON) from the
front-panel LINE switch. First check the +12 Vdc supply to the fan at
the Rear Frame.
1. Disconnect the line-power cord from the analyzer.
2. Look through the fan grill. If the cables routed near the fan are
3. Remove the fan from the rear frame and disconnect its wiring
4. Reconnect line power to the analyzer and turn it on.
5. Refer to "A15 Motherboard Assembly" in
6. Check that pin 2 on A15J19 is connected to digital common-ground
7. Check pin 1 on A15J19 for +12 Vdc.
Chapter 4
jammed in the fan, remove the fan from the rear frame, reroute the
cables, and remount the fan.
connector from A15J19.
identification of the fan-supply connector, A15J19, and the A8
power-supply connector, A8J1.
(DCOM). If the ground connection is open, suspect the A15
Motherboard.
If the +12 Vdc is present, check for a defective B1 fan assembly by
connecting the fan to an external DC supply.
Troubleshooting the Analyzer
Troubleshooting an Inoperative Analyzer
Chapter 5 for the pin
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