Figure 5-30. Rf Power Amplifier (Rfpa)-No Or Low Tx Power Output - Motorola ASTRO Digital XTL 5000 Detailed Service Manual

5-40
5.6.26 RF Power Amplifier (RFPA)—No or Low TX Power Output (380–470 MHz and
450–520 MHz)—Part 1 of 5
NOTE: For each flowchart step in which reference is made to a note, be sure to refer to that specific
note (located on page 61 of this flowchart) for guidance in performing the actual
troubleshooting procedure. Also, RFPA DC voltages are shown in
START
Read General
Notes before
proceeding. Read
specific notes as
indicated
Check battery
cable, mic, and
control head
connections
Continuous red light
while mic button is
depressed?
Yes
Tune power with
Tuner?
(see help text)
No
TX injection power
less than 0.5 mW?
(Note 1)
No
Figure 5-30. RF Power Amplifier (RFPA)—No or Low TX Power Output (380–470 MHz and 450–520 MHz)—
May 25, 2005
power control section
when transmitter is
voltage (TP5503)
less than 4.8 V when
GOTO Sythesizer-
No
No Transmit
VCNTRL resistance <
Chart
Tune current limit
Yes
U5501 drain biases
with Tuner
voltages per Table 1?
(see help text)
GOTO Sythesizer-
Yes
No or Low Tx
Injection
Chart
Part 1 of 5
K9.1V
present
GOTO Power
at Q0952, pin 1 in
No
Control - No K9.1V
Chart for
700-800 MHz
keyed?
Yes
RFPA_CNTRL
GOTO Power
No
Control - No or low
RFPA_CNTRLChart
transmitter is
for 700-800 MHz
keyed?
Yes
Is U5501,
Yes
Repair/replace
1 kOhms? U5501
(Note 2)
No
Check/repair/
No
replace defective
(Note 3) parts
Yes
Is U5501,
RFOUT and VD1
Yes
Repair/replace
resistance <
U5501
1 MOhms?
(Note 4)
No
A
Troubleshooting Charts: Flowcharts
Table 5-6 on page
6881096C74-B
5-44.