Longitudinal Binding - GE Medical Systems PRODIGY Service Manual

4.2.2 Longitudinal Binding

Turn off the power to the scanner and move the affected parts by hand. Feel
the motion for spots where the arm is more difficult to move. Listen for unusual
noises.
The major impediment to longitudinal motion is the plastic Cable Track that
runs through the trough at the rear of the scanner.
This track is attached at two points: at the Rear Longitudinal Carriage and to
the scanner frame (low, rear and center) each spot by 4 bolts. Also, adequate
slack must be left in the cables inside the Cable Track or they will stop the arm
from moving fully to the foot end.
Should the Cable Track detach from the scanner frame, it will slide freely in
the trough and will eventually cause trouble. This can allow the Cable Track to
get in between the Rear Longitudinal Carriage and the scanner frame on the
foot end preventing the tripping of the limit switch.
Check the distance between the front longitudinal carriage and the
longitudinal rail with a go/nogo gauge (See installation Procedure DXAP2000
Chapter 5 appendices). The carriage should not rub the front rail, if necessary
insert shims behind the front longitudinal carriage.
DPX-NT Service Manual (Rev A- 1999)
• Cause: When scanning, a defect in the longitudinal mechanics (binding)
or a mis-positioned patient may cause one of the longitudinal limit
switches to close when the scanner is acquiring data. Closure of a limit
switch prevents further operation of the motor. The shutter will close, the
shutter open lamp will go out and the end of exposure alarm will sound.
Seconds later the error message will appear on the screen.
Solution: If the patient is not centered on the table top (length wise) or if
the region being scanned is too close to a limit in longitudinal travel, the
limit switch may be close while scanning. Re position the patient on the
table, further away from the limit.
• If the scan arm fails to move when scanning check the stepper motor,
and Centent, if arm motion is irregular, check for binding.
• Cable Track
• Front Longitudinal Carriage Dragging
• Tube Head Cable Routing
When moving the arm longitudinally, only
push on the arm column. Pushing on the
forward parts of the arm can ruin Tube
Head/Detector alignment.
Troubleshooting 4-123