GE Medical Systems PRODIGY Service Manual page 156

6.0.6Tests
Run all other tests according to the Prodigy PM check sheet.
6.1 Unusual Sounds
A high pitched sound is normally heard when the scanner is in motion. This is
caused by the high frequency motor pulses being sent from the Centent Motor
Controller to the Transverse and Longitudinal Motors.
If the high pitched sound only occurs during motor operation, check the optical
interrupt disks and verify that they are not rubbing against the black plastic
transducer of the OMI board (see section 5.x). The disk should turn in the
middle of the transducer's slot.
For other sounds of an apparent mechanical nature, check all appropriate
gears and pulleys. Verify that the set screws are tightened and that the gears
and pulleys are not out of position. With the scanner turned off, move the
affected parts by hand to determine the exact source of the sound. Also look
for rusted or worn bearings and examine the V-wheels for wear. With age, the
longitudinal and transverse drive belts will dry out and start to cause noises.
Treating these belts with belt dressing is a short term solution until they can
be replaced.
Clicking or clunking sounds made during motor operation can be caused by
belts that are riding up on their pulleys, or by a too tight bearing support. The
bearing support is held to the carriage by a set screw from the rear. If this set
screw is so tight that the bearing and support have no play (i.e. can be rocked
1-2 mm), it can cause a clunking sound during transverse motion. If this
screw is loosened, it should be secured with Lock-Tite so it cannot work its
way loose.
Pulleys that have become defective can also cause clicking and squeaking/
squealing sounds. Try to isolate the movement of individual pulleys to locate
the defective part.
Scraping sounds can be caused by any of the moving carriages, cables or
cable track rubbing against an adjacent panel. Localize the sound and
investigate the appropriate areas.
6.2 Change Orders
As engineering changes are made to the Prodigy Scanner, they will be noted
herein future revisions of this manual.
6-170Maintenance
• Inspect the scanner internally and externally for obvious damage and
loose connections.
• Check all PCB's for tight mounting screws.
PRODIGY Service Manual (Rev B - 1998)