Fluke Biomedical 943-35 - Manual (Page 15)

Maintenance, Calibration, and Troubleshooting
Maintenance
4
4-1
Section 4
Maintenance, Calibration and Troubleshooting
4.1 Maintenance
The 943 series Gamma Scintillation Detector requires no routine maintenance. Periodic verification of the
high voltage and discriminator setting supplied by the readout device, however, is recommended. If the
detector requires repair, the following assembly/disassembly procedure is to be used.
Ensure all power is removed prior to disassembly of
the 943 Series Detector.
Detector Disassembly
If additional information is required, refer to the
assembly drawing in Appendix A.
1. Disconnect the cable from the readout device.
2. Remove the four flat head hex screws from the detector sleeve (connector end).
3. For the 943-35, 943-37, and 943-237A detectors, using the detector cable, gently pull the detector
end plate, preamp, and photomultiplier/crystal assembly out from the detector sleeve. The
photomultiplier/crystal assembly may then be removed from its socket for replacement and/or the
preamplifier circuit board may be repaired.
4. For the 943-36 and 943-36H detectors, the crystal assembly must be separated from its socket
while removing the detector end plate. This may be accomplished by applying a slight rocking
motion while gently pulling on the detector cable.
To remove the photomultiplier/crystal assembly, the RTV used to seal the front end of the detector
must be removed to expose and remove the 38-34 outer retaining ring. Next, the 38-35 crystal
retaining ring and 843-36-51 crystal mounting with o-ring may be removed, followed by the 38-34
inner retaining ring. The photomultiplier/crystal assembly may then be removed for replacement.
Use extreme care when removing the detector
preamplifier and photomultiplier assembly to
prevent damage to these delicate components.
5. The o-rings in the assembly may be remove with a small screwdriver, using care not to damage the
o-ring.
CAUTION
NOTE
CAUTION