Del Medical EPEX Omniflex IV, Service Manual

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EPEX/Omniflex IV System Service Manual
Adjustments and Calibration 4-43
AEC Limitations: Maximum Exposure Times
For diagnostic radiography, the FDA limit I
≥
600 mAs in AEC.
AEC Board
The AEC board shown below is compatible with various makes/models of
ion chambers (for example, AID, GE, Vacutec, Philips Amplimat). This
AEC board is used as the Generator requires short AEC time
compensation.
The EPEX board is fitted with 12 pin in
-
line connectors (J1 to J4).
Figure 4-9.
Dedicated Ion Chamber
AEC Boards
Note: Do not adjust unless
the AEC preamp calibration
is out of range.
AEC board input assignment: Ch 1 = J1/J11.
The R1 potentiometer is used for channel 1 AEC gain adjustment.
The R11 potentiometer is used for channel 1 short AEC exposure time
compensation.
R79 adjusts the output of the high voltage bias supply. This is only fitted on
versions of this board intended for use with ion chambers which require a
separate high voltage bias supply. R79 adjusts the value of the +300 and/or
the +500 and the +45 Vdc outputs, and should be set as per the ion chamber
manufacturer specifications.
AEC DEDICATED ION CHAMBER
R79
R11 R12 R13 R14
R1 R2 R3 R4
J14
J13
J12
J11
J4
J3
J2
J1
CPI CANADA INC.
Made in Canada
J5
MC20_151.CDR