Universal APX 525 - Long Exposure Times with Light Films; Long Exposure Times with Dark Films; Apparent Small Focus Open Filament Condition; No Ma Feedback

APX 525/625 Generator Revision C Diagnostics
© 2005 Del Medical Imaging Corporation
7/5/2005 Page 174
Additional Problems and their Possible Causes
Symptom Possible Cause Corrective Action
Low Tube Current
Incorrect Filament drive –
Check DC supply to
switching transistors, as
well as switching
waveform
LONG EXPOSURE
TIMES WITH LIGHT
FILMS
Low kV
Possible feedback or
reference voltage errors
– Check reference and
feedback voltages on kV
Regulator board
Incorrect mA feedback,
resulting in excessive
actual mAs
Check mA feedback for
accuracy (2V = 100 mA)
mAs timing error
Check mAs with
Dynalyzer™ or mAs
meter
LONG EXPOSURE
TIMES WITH DARK
FILMS
Photo timing (AEC)
Errors
Check adjustment of
photo timer and ion
chamber pre-amps
APPARENT SMALL
FOCUS OPEN
FILAMENT CONDITION
Possible problem with
K11 relay on I/O Board
Check for activation and
proper operation of K11
relay when small focus is
selected
NO mA FEEDBACK
Possible short in
feedback cable or other
components
Check resistor R3 on
Motherboard. Resistance
should be approximately
20 Ohms. Check
capacitor C4 on
motherboard for possible
short.
NO kV FEEDBACK OR
IMPROPER kV
FEEDBACK
Possible shorted
component or bad
connection in feedback
cable
Check Diodes CR1 and
CR2 on Motherboard.
Resistance in circuit
should be approximately
18.5 K Ohms (typical)