9600 Service Manual - gmecorp-usa.com

2 mA Generation
CONTROL INPUTS
The Technique Processor commands the Analog Interface to generate four primary
control signals to the X-ray Regulator PCB. Their purpose is to initialize and control the
mA servo loop. These signals are:
• FIL B CONTROL
• MA CONTROL
• FILDRVA
• FILDRVB
FIL B CONTROL
This is a current signal from the Analog Interface PCB A/D U18-6. This current signal is
converted to a positive DC voltage by the current to voltage converter U28 (pins 2 & 1).
This signal is software controlled in response to the X-ray mode currently selected. It is
used to set up the Filament Regulator on the Generator Driver PCB for the proper output
voltage as shown in Table 1. The Filament Regulator output voltage can be measured at
the collector of Q4 or at R8 on the Generator Driver PCB.
Fluoro =160 VDC with X-rays off
0.3 mm Film = 175 VDC, Armed 160 VDC
0.6 mm Film = 185 VDC, Armed 140 VDC
Table 1 - Approximate Filament Regulator Output Voltage
The ratio between the FIL B CONTROL voltage and the Filament Regulator output
voltage is approximately 1:40, for every +1VDC on TP10 of the Analog Interface, the
filament regulator’s output will be approximately +40 VDC. See Filament Regulator
Setup, later in this section, for more information.