Stanford Research Systems RGA100, Operating Manual And Programming Reference

Page: 233 / 362

Circuit Description 10-5
SRS Residual Gas Analyzer
Circuit Boards
There are two main PCBs inside the ECU package.
The top PCB has the CPU, RS232, digital ports, the analog electronics for A/Ds and
D/As, and the RF amplitude detection circuit. A small vertical PCB which holds the log
I/V converter connects to the top PCB. A second small vertical PCB holds the electron
multiplier’’s HV supply. A third small vertical PCB is used to pass signals and power
between the two main PCBs.
The bottom PCB holds all of the power electronics for the RF, filament heater, ionizer
bias, and system power supplies.
Four PCB’’s between the two main boards are used:
1. To connect to the probe.
2. For the I/V converter.
3. To pass signals between the main boards.
4. To supply High Voltage to the CDEM.