138 Chapter 6
Troubleshooting the IF Section
Verifying the A8 Analog IF Assembly Signal Path
Testing the Cal Osc Signal
The 21.4 MHz Cal Osc HI and Cal Osc LO signals are routed through
the motherboard to the A10 Third Converter. The E4440-60048
extender board has test jacks for both of these signals. The following
waveform was taken using an oscilloscope with a SMB to BNC cable
connected to a BNC tee/50 ohm load at the oscilloscope input connector.
The waveform is only visible while the Auto Align Now routine is
running.