HP 5973 MSD Hardware Manual page 82

 Troubleshooting
1R RU ORZ UHDJHQW JDV VLJQDO
Possible Cause
Too much air or water in the system.
Action
Run the methane pre-tune. Peaks at m/z 32 and 19 usually indicate air and water,
respectively. Bake out and purge the instrument until the peak at m/z 32 is smaller
than that at m/z 31 and the peak at m/z 19 is reduced to a very low level. If the peak
at m/z 32 does not decrease, an air leak is likely. See the Leaks section at the end
of this chapter for more information.
Possible Cause
The signal cable is not connected.
Action Check and, if necessary, reconnect the signal cable.
Possible Cause
The filament or filament support is shorted to the ion source body or repeller.
Action
Inspect the filament. If necessary, realign the filament support arms.
Possible Cause The electron inlet hole is blocked.
Action
Inspect the electron inlet hole. If necessary, clean the hole with the supplied
0.016-inch drill bit. If the electron inlet hole is that dirty, the entire ion source
probably needs to be cleaned. See the Maintenance chapter in this manual for
more information.
Possible Cause
Ion source wires are not connected, or incorrectly connected.
Action
Inspect the repeller. Make sure the repeller lead is firmly attached to the repeller.
Inspect the wires to the ion focus and entrance lenses. If the connections are
reversed, correct the problem.
Possible Cause One of the electron multiplier leads (in the vacuum manifold) is not connected.
Action
Check and, if necessary, reconnect the electron multiplier leads.
Possible Cause
Saturated methane / isobutane gas purifier.
Action
Replace the gas purifier.
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