Owandy Radiology i-max touch, Service Manual

Page: 25 / 267

SERVICE MANUAL
Description
I-Max Touch 3-9
3.3.3. Generator Board (A10) and Tubehead
The Generator board and the tubehead are located on the rotating arm,
very close to each other. The power supply voltage is directly provided by
the Power supply assembly.
Dedicated switching circuits, directly located on the board, generate the
voltage used on the board itself.
Managing of the Generator board is done by the dedicated Generator CPU
board (A9) that is interfaced with the main CPU board (A5) using the
CANBus cable (X20-X20). This cable also has a dedicated wire to bring
the X-ray button signal to this board, so the "dead man switch" method
is generated directly on the board.
The high frequency (HF) circuit is based on an inverter circuit working at
the frequency about 100kHz, which drives the tubehead through an
output stage based on IGBT components.
The Generator board receives the signals concerning the X-ray dose to
provide (kV and mA), from the CPU board through CANBus messages; it
is the Generator CPU that generates the commands used for the X-ray
emission. The Generator board provides to the tubehead the voltages that
drive the high voltage transformers that then drive anode and filament of
the X-ray tube, also giving the relevant timing.
The tubehead is composed by the X-ray tube (CEI OPX/105) inserted in a
sealed container, together with the high voltage transformers, filled with
dielectric oil.
Checking of proper functioning of the X-ray emitting system is achieved
through the analysis of feed back signals generated inside the tubehead
and transmitted to the Generator board and relevant Generator CPU.
Possible anomalous conditions are then communicated to the main CPU
board (A5) which in turn generates error codes to alert the operator.