M70706
PHOTOMULTIPLIER POWER SUPPLY
10
6 TROUBLESHOOTING
6.1
FAULT DIAGNOSIS
If operational problems are encountered, the configuration of the instrumentation should be checked
before the power supply is considered defective. The following list of externally recognizable problems is
provided to assist in this determination.
•
No power on indication and meter not illuminated
Check connection to AC supply and fuse(s).
•
Output can not be adjusted from the front panel
First, disconnect the load from the high voltage BNC connectors. If this does not alleviate the
problem, check that Remote Enable on rear panel is switched
off
or, if Remote is elected, that the
binding posts do in fact have a low level TTL signal or a contact closure/short circuit applied. Check
that the rear panel Output Voltage Control is set to the Front Panel position.
•
Output can not be adjusted using remote voltage control
Check as above except Output Voltage Control
must
be set to
Remote.
Verify that appropriate control voltage is being applied.
•
Remote enable function not effective
Check switch selection on rear panel. Measure control levels at Remote binding posts to be either
TTL (<0.8 VDC low, >2.4 VDC high) or, with contact closure, 0 volts for a low and 5 volts for a high.
Note that the output voltage response to a high level on this control input may require several
seconds for full decay if lightly loaded.
If the above checks have not resolved the problem, contact the Customer Service Department to arrange
for service.
< < < W A R N I N G > > >
POTENTIALLY LETHAL VOLTAGE LEVELS EXIST WITHIN THIS UNIT WHEN POWER IS APPLIED
AND FOR MANY MINUTES AFTER POWER HAS BEEN REMOVED. NEVER REMOVE THE COVER
FROM THIS UNIT.
