Motorola StarTAC 160 Service Manual page 36

Table 7: Receiver Troubleshooting and Repair Chart
RX Symptom
2. Receive audio
is weak and/or
distorted.
Table 8: Transmitter Troubleshooting and Repair Chart
TX Symptom
1. Transmit
audio is weak,
(usually indi-
cated by called
parties
complaining of
difficulty in
hearing voice
from portable
phone).
2/6/98
Probable Cause
c) Logic/RF Board Assembly
defective.
Probable Cause
a) Microphone connections to
Logic/RF board defective.
b) Microphone defective.
c) Logic/RF Board Assembly
defective.
Verification and Remedy
1. Replace Logic/RF Board Assembly.
2. If substitute Logic/RF Board Assembly
works, the original is faulty and should be
examined for improper solder and/or
connections. Likely fail components: J601,
U500, U900.
Verification and Remedy
1. Gain access
described in "Disassembly" on page 19.
2. Check connections (including checking for
polarity) and if OK, proceed to b.
1. Gain access to microphone.
2. Disconnect and substitute a known good
Microphone.
3. Place a call and verify improvement in
portable transmit signal as heard by called
party. If good, re-assemble portable with
new Microphone.
4. If Microphone is not at fault, re-install orig-
inal Microphone and proceed to c.
1. Replace Logic/RF Board Assembly.
2. If Logic/RF Board Assembly is at fault,
examine it for improper solder and connec-
tions. Likely fail components: Q300, Q303,
U201, U300, U301.
Issue 1.0
Troubleshooting
to the Microphone as
29