626 Internal Mod Source Unlock - Agilent Technologies PSG Series Service Manual

Troubleshooting
Troubleshooting Unlocks

626 Internal Mod Source Unlock

A 626 Internal Mod Source Unlock error message indicates a problem with the digital 10 MHz signal to the
A11 Pulse/Analog Modulation Generator. This error message is turned on if the signal generator is in phase
modulation mode and there is a problem with the 10 MHz digital signal to the in phase clock.
1. Set the signal generator to phase modulation mode.
2. Measure pin P131-91. The waveform is not a sine wave, but more like a distorted pulse waveform >2 V .
p-p
3. If the waveform is present, replace the A11 Pulse/Analog Modulation Generator.
4. If the signal is not present, replace the A7 Reference.
1-48