Dig Syn En Line - Tait TM9100 Service Manual

If the supply for the charge pump and the reference frequency are correct,
Task 9 —
Line
DIG SYN EN
check the
1.
2.
3.
4.
5.
6.
7.
8.
9.
184 Frequency Synthesizer Fault Finding
line input.
DIG SYN EN
Check the line at pin 10 of IC503 (see
DIG SYN EN
Enter the CCTM command 334 0 to switch off the synthesizer, and
measure the voltage at pin 10.
pin 10 of IC503: 0 V DC (after entry of CCTM 334 0)
Enter the command 334 1 to switch on the synthesizer, and measure
the voltage again.
pin 10 of IC503: 2.5 ± 0.3 V DC (after entry of CCTM 334 1)
If the voltages measured in
Task 10. If they are not, go to
Remove R104 (see Figure
as follows:
Enter the CCTM command 334 0 to switch off the synthesizer, and
measure the voltage at the via between R104 (see
the digital board.
via at R104: 0 V DC (after entry of CCTM 334 0)
Enter the CCTM command 334 1 to switch on the synthesizer, and
measure the voltage at the via between R104 (see
the digital board.
via at R104: 3.3 ± 0.3 V DC (after entry of CCTM 334 1)
If the voltages measured in
digital board is faulty; replace the main-board assembly and go to
"Final Tasks" on page 147. If the voltages are correct, go to
There is a fault between the digital board and IC503. Locate the fault.
Check and resolder R104 in position (see
continuity between pin 10 of IC503 (see
board via R104.
If there is a fault, repair the circuit, confirm the removal of the fault,
and go to "Final Tasks" on page
could be found, replace the main-board assembly and go to
Tasks" on page 147.
Figure
Step 1 and Step 2 are correct, go to
Step 4.
9.6) and repeat the above measurements
Figure
Figure
Step 5 and Step 6 are still not correct, the
Figure 9.6), and check for
Figure 9.2) and the digital
147. If the repair failed or no fault
TM9100 Service Manual
© Tait Electronics Limited August 2005
9.2).
9.6) and
9.6) and
Step 8.
"Final