Motorola 38C V100 Service Manual page 39

Level 3 Service Manual
Transmit power is low?
YES
Problem occurs on all
bands?
YES
1. Connect a spectrum analyzer to
EXT CONN TP1:
2. Place UUT into manual test
mode, then enter 9823# (change
GSM mode), 110062# (GSM
ARFCN), 1215# (TX level), and
310# (Pseudo-random TX).
3. A signal is present but it is low?
YES
1. Check signals on U350:
- Pin 6: SF_OUT (from L350, U200)
- Pin 5: TX275_DPCS, if DCS/PCS
channel is selected. (If not present, see
"H" Figure 22. "No Transmitter Control
Matrix".)
- Pin 3: TX275_GSM, if GSM channel is
selected. (If not present, see "H" Figure
22. "No Transmitter Control Matrix".)
- Pin 2: TX275_DCS, if DCS/PCS channel
is selected. (If not present, see "I" Figure
23. "PIN Diode Band Select".)
See Note 1
Figure 19. Device Will Not Transmit (Sheet 1 of 2)
6881036B20
NO
M
NO
H
NO
C
MOTOROLA CONFIDENTIAL - PROPRIETARY
November 20, 2000
In most cases, a reference board can be
used to compare signals.
If unit passes "H" tests (see Figure 22. "No
Transmitter Control Matrix") check U300 and
CR300 thru CR306.
See Note 1
Note 1: Check components for correct
orientation, cold solder joints, physical
damage, and functionallity.
Troubleshooting
35