APX 525/625 Generator Revision C Diagnostics
©
2005 Del Medical Imaging Corporation
7/5/2005 Page 171
1. Turn off power to the generator and allow the inverter capacitors to discharge for
5-10 minutes
Verify with a voltmeter that 0 VDC is measured across the inverter filter capacitors.
Caution: Dangerously high voltages are present on the inverter filter capacitors
whenever power is applied to the generator. Do not attempt to make any
measurements in this circuit using an ungrounded or “floating” scope configuration.
All measurements must be made using an oscilloscope in a differential input
configuration. If necessary, refer to the documentation for your oscilloscope for
instructions on performing differential voltage measurements.
2. Connect a dual channel oscilloscope differentially across the DC rails and adjust
the vertical scale so that you can measure between 350 to 400 VDC
3. Turn generator on and observe the DC rail as well as during a full power
exposure (60 kV, 100 mAs, Large Spot) and determine if there are any
abnormalities or excessive ripple. You can set the scope for AC to be able to
measure the amplitude of the ripple as well
Check for a breakdown in the high-tension tank
1. Perform a no load test. See “No Load Test” in this section
2. If available, connect a “loaner” X-ray tube with a different pair of high voltage
cables
3. Turn on power and make an exposure. If problems persist, the problem may be
in the high-tension tank. Otherwise, permanently replace the X-ray tube or high
voltage cables
Check SCR Delay firing adjustment
1. Turn off power to the generator
2. Place the kV Regulator board on an extender card
3. Use an oscilloscope set for a time sweep of 50 microseconds/Div. and connect
the probe between U3-10 and ground
To Next Page
Loading...