[time-nuts] 5061A troubleshooting
corby d dawson
cdelect at juno.com
Tue Sep 30 13:11:01 EDT 2008
The -.210 v one the multiplier is OK for now. The tube value is for when
the tube was originally tested. As the electron multiplier in the tube
ages the required voltage needs to be increased (up to a maximum of
If you have a manual I would suggest that you do the low frequency test.
It takes a frequency at 1/2 the zeeman frequency that you apply to a pin
on the underside of the unit on the long terminal board.
This allows you to test the tube even if the RF circuitry is at fault.
If the low frequency test fails then before blaming the tube you need to
get in and measure the ionizer voltage (older units a 1VRMS square wave,
new units 1VDC) and also measure the mass spectrometer voltage with the
pot at max CW (about +17 to 18VDC.
If everything checks out but low freq. test still fails increase the EM
voltage to 2500VDC and repeat the test.
If no low frequency response by now the tube has a high probability if
If the test is good then your problem lies in the RF circuitry
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