OEC 9800C-Arm, Service Manual

Page: 147 / 490

kV Generation
Failure Possible Cause Remedy
No Image and kV tracks to
120. Anything in the kV
generation circuit or Image
path. Check the FLUX_SEN on the Generator Driver or X-Ray
Controller to see if the flux is unstable and varying from the
nominal value
This is more often a software problem, but can arise from a
filament failure or the system not coming out of “sleep” mode
when it should. Try making manual exposures at low
technique values, which should give some output.
Various Errors Peak voltages on IGBT’s
could exceed ratings and
cause early failure. Snubber
components damaged or
defective. The capacitors are rated for at least 400V. The current ratings
are also adequate for this duty. If any of these components
fail, the high voltage supply to the PCB is protected by a fuse,
and if this fuse blows, the Filament Driver PCB will not operate.
An open failure could result in larger voltages occurring at the
outputs, but there is also a snubber across the supply at Q2
which will tend to prevent this condition.
7
Service Periodic Maintenance Contents Schematics Illustrated Parts Installation