Tait TM8100 mobiles Service Manual page 252

Figure 10.4 Receiver circuitry under the FE TOP and IF TOP can (K5 band only)
Task 3 —
Check Logic Signal
252 Receiver Fault Finding
If there is no fault with the power supplies, check the logic signal
that is input from the digital board.
1. Check the logic signal
The signal is active high. The required status is active.
pin 8 of IC403: about 3.0V (active)
An alternative measurement point to the above is pin 24 of IC400
under the
IF TOP
2. If is active, go to
DIG RX EN
3. Check the signal continuity from the digital board to the receiver.
Repair any fault and go to
be faulty, replace the board and go to
4. Recalibrate the receiver using the calibration application.
5. Confirm the removal of the fault and go to
page 163. If the repair failed, go to
IC405
at pin 8 of IC403 (see
DIG RX EN
can (see Figure 10.1).
Task 4. If it is not, go to
Step 4. If the digital board itself appears to
"Final Tasks" on page
Task
© Tait Electronics Limited November 2007
IC409
IC404
DIG RX EN
Figure 10.2).
Step 3.
163.
"Final Tasks" on
7.
TM8100/TM8200 Service Manual