APX 525/625 Generator Revision C Diagnostics
©
2005 Del Medical Imaging Corporation
7/5/2005 Page 172
4. Turn generator on. Select 60 kV and 10 mAs. Make an exposure and measure
the off time between pulses at the very beginning of the exposure. It should be
140 microseconds
5. If necessary, adjust R65 on the board
Note: If you are not quite sure about how to perform this adjustment it may be better
to simply replace the board. Maladjustment of R65 can cause severe malfunction
and possible permanent damage to the generator! It is rare that this adjustment
needs to be made in the field.
Check if commutation capacitor relay changeover circuit is not switching or
has pitted contacts
1. Turn off power to the generator and allow 5-10 minutes for the inverter capacitors
to discharge
2. Verify with a voltmeter that the voltage is 0 VDC across the inverter capacitors
3. Check the contacts of K1 or K2 located at the rear left interior of the power
module, below the commutation capacitors. If contacts are in poor condition,
replace the relays
4. Turn generator on, select 80 kV, and increase the mAs from minimum, observing
the sequence of the relays energizing and de-energizing
5. If the relays don’t energize, check the voltage at each relay coil while repeating
step 3. If the voltage is present, then change the defective relay
6. If no voltage is ever present, turn off generator power and place mAs Control
board on an extender card and check for switching voltages at Q1, Q2 and Q3.
Replace the board if necessary
Possible causes for an open F1 fuse
• Break in the primary circuit to the high voltage transformer (e.g.: a bad
connection or incorrect wiring)
• Short in the primary circuit to the high voltage transformer (perhaps
shorted to ground, e.g. the primary connection cover or incorrect
wiring)
• Short in the inverter (e.g.: a shorted SCR)
• Short (arcing) in the secondary, HV Cables or X-Ray tube
• Line Voltage Drop (consult the power requirements documentation)
• Gross maladjustment of the filament pre heat
• Gross maladjustment of the SCR hold off adjustment
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