TP9100 Service Manual Frequency Synthesizer Fault Finding 209
© Tait Electronics Limited May 2005
Task 36 —
VCTCXO Output
If the VCXO output is correct, check the VCTCXO output as follows:
1. Use the oscilloscope probe to check the VCTCXO output at pin 4
of IC500 (see Figure 9.19). The signal should be:
2. If the signal is correct, go to “Signals at TP501 and TP502” on
page 210. If it is not, go to Step 3.
3. The VCTCXO module XL500 or its supply voltage is faulty.
4. Locate and repair the fault of XL500 and associated components
(see Figure 9.21).
5. Confirm the removal of the fault and go to “Signals at TP501 and
TP502” on page 210. If the repair failed, replace the main board and
go to “Final Tasks” on page 134.
VCTCXO output at pin 4 of IC500: 13MHz±1.5ppm, 3V
pp
square
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