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ANALOG SUBSYSTEM ASSEMBLIES | SYSTEM DESCRIPTION |
A7 PCB, LO3 The A7, Third Local Oscillator (LO3) Assembly, provides a fixed
2.42MHz Local Oscillator signal that is used on the A3, A4, and A6 PCBs to
A5 A/D Converter PCB The A5 A/D Converter PCB contains a
The A5 A/D Converter PCB also derives the 109.89 kHz Power Supply Synchronization Signal and the 80 kHz IF Synchronization Signal from the 10 MHz Reference Timebase. Additional functions of the A5, A/D Converter Assembly include:
Measurement of power supply voltages and other internal nodes of the 372XXB for diagnostic purposes.
Measurement of an externally applied analog input signal. This function is used for service purposes only.
External Trigger Input signal processing (from rear panel)
External Analog Output signal generation (to rear panel)
The A/D converter circuitry located on the A/5 PCB is used as a DVM to measure various internal system analog monitor points on the
A1 – A8 and A21A1/ A21A2 PCBs. It is also used to monitor power supply voltages and other critical points throughout the 373XXA, which can be readout via the Diagnostics Menus. DVM readings are also recorded in the service log for certain system failures.
373XXA MM |