210 Frequency Synthesizer Fault Finding TP9100 Service Manual
© Tait Electronics Limited May 2005
9.10 Signals at TP501 and TP502
Introduction If the VCXO and VCTCXO outputs are correct, the next stage is to check
the signals at the
TP501 and TP502 test points. The procedure is divided into
three tasks:
■ Task 37: check signal at TP502
■ Task 38: check signal at TP501 and ground TP501 if loop is oscillating
■ Task 39: check signal at TP502 with TP501 grounded
These checks will reveal any faults in the mixer and LPF (low-pass filter)
circuitry, and any additional fault in the VCXO circuitry.
Figure 9.21 Test points TP501 and TP502 (bottom side)
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