Mhz)-Part 2 Of 5; Rf Power Amplifier (Rfpa)-No Or Low Tx Power Output - Motorola ASTRO XTL 1500 Detailed Service Manual

5-38
5.6.27 RF Power Amplifier (RFPA)—No or Low TX Power Output (380–470 MHz and
450–520 MHz)—Part 2 of 5
A
Defective parts
in matching network
between U5501 and
Q5502?
(Note 5)
No
Q5502 bias voltages
as per Table 1?
(Note 6)
Yes
Is Q5502,
gate resistance <
1 MOhms?
(Note 7)
No
Is Q5502,
drain resistance <
1 MOhms?
(Note 8)
No
Defective parts
in matching network
between Q5502 and
Q5503?
(Note 9)
No
Figure 5-29. RF Power Amplifier (RFPA)—No or Low TX Power Output (380–470 MHz and 450–520 MHz)—
June 15, 2005
Yes
Repair/replace
defective parts
Check/repair/replace
defective parts or
No
GOTO Power Control
- No/low VGBIAS
Chart
Repair/replace
Q5502 and retune
Yes
gate bias via
Tuner
(see help text)
Repair/replace
Q5502 and retune
Yes
gate bias via
Tuner
(see help text)
Yes
Repair/replace
defective parts
Part 2 of 5
Troubleshooting Charts: Flowcharts
Q5503 bias
No
voltages as per Table 1?
(Note 10)
Yes
Is Q5503,
Yes
gate resistance <
1 MOhms?
(Note 11)
No
Is Q5503,
drain resistance < Yes
1 MOhms?
(Note 12)
No
Defective parts
in matching network
Yes
between Q5503 and
antenna switch?
(Note 13)
No
Antenna switch
No
bias voltages as per
Table 1?
(Note 14)
Yes
B
Check/repair/replace
defective parts or
GOTO Power Control
- No/low VGBIAS
Chart
Repair/replace
Q5503
(see General Notes)
and retune gate bias
via Tuner
(see help text)
Repair/replace
Q5503
(see General Notes)
and retune gate bias
via Tuner
(see help text)
Repair/replace
defective parts
Repair/replace
defective parts
6815854H01-A