Midmark Preva - Page 83

Preva Installation/Service Manual, 00-02-1577, Revision E01
80
X-ray Indicator,
No Exposure
Termination, No
Radiation
Produced
1. Check if both audible indicators operate. Check the Operator Panel first,
and check the Logic Board second.
2. If only the Operator Panel indicator works, check if diode “D2” on the
Power Supply Board and “D11” on the Logic Board illuminate during the
exposure request.
3. If “D2” and “D11” do not illuminate, this indicates that the “X-ray backup”
conductors in the CAT 5 communication cable are open.
4. Connect a substitute communication cable to test for this condition.
5. If the symptom persists, contact Technical Support.
Display Shows
“Error – Serial
Communications”
If the ribbon cable is open between the Logic and Power Supply Boards,
replace the cable.
Display Shows
“Pre-termination
Error”, Early
Exposure Release
Determined Not to
be the Cause
This error can be caused by a high voltage breakdown in the head and is
characterized by a snapping or popping noise within the Tubehead.
1. Inspect the condition of the feedback cable.
2. Inspect the condition of the communication cable.
3. If used, inspect the remote exposure switch wiring for a loose connection.
4. Refer to the High Voltage Breakdown information in the Troubleshooting
section for detailed instructions.
All X-ray
Indicators, But No
Voltage Measured
at J1 on the
Power Supply
Board
Replace the Power Supply Board [30-08041].
Very Short
Exposures,
Regardless of
Selected
Exposure Time
This condition will exist if the kV or mA produced is out of tolerance. To
address this issue:
1. Inspect the condition of the high voltage circuit by operating the Preva
in the diagnostic mode. Confirm incorrect kV or mA.
2. Inspect the Preva’s internal horizontal and articulated arm wiring.
Repair as necessary.
3. If wiring is intact, and the firmware revision is 5.0 or less, attempt
system recalibration. If greater, replace the Logic PCB Assy (30-
08160).
4. If calibration cannot be achieved, the problem may require
replacement of the tubehead assembly. Contact Midmark technical
support for further assistance.
5. Check if D14 “DIAG” LED (Logic Board) is on. If so, check that DIP
Switch #2 (J11, Logic Board) is in the correct position for the brand of
X-ray tube in the unit. The label on the tubehead will indicate either
Canon (Toshiba) or Kailong. DIP Switch #2 should be in the OFF
position for Canon (Toshiba), ON for Kailong.