Motorola ASTRO Digital Spectra Plus Service Manual page 173

Troubleshooting Procedures: Power Amplifier Procedures
RX MODE
LOCATION
LOW
29 —
30 —
31 0
32 10.8 13.6
33 4.0
34
35
36
37 10.8 13.6
38 10.8 13.6
39
40 1.5
41 0
42
43
44
Q0500E 13.0
Q0501C 12.3
Q0501E
Q0503E
Q0503C 13.6
Q0504B 13.6
NOTE: For antenna switch transmit bias conditions, RF drive must be removed from PA.
6881076C25-D
Table 4-11. Power Control DC Voltage Chart (Continued)
TX MODE
TYP HI LOW TYP
— — — —
— — — —
0 0 0
16.5 10.0 13.0
5.0
0 1.3
0
0 0.8
16.3 10.0 13.0
16.3 10.0 13.0
0 9.2 9.4
3.0 4.5 1.5 3.0
0 0 0
0 2.2
1.3 7.0
2.1 3.2
13.0
12.3
0.2 0.2
0 1.5
9.0
12.9
HI
— 9.6-V Programming (N.C.)
— 9.6-V Programming (N.C.)
0 0 Ground
16.0 Decoupled A+
0 0.2 TX PA Enable (from U520-25)
Control AMP one-shot
0 Lock (5-V of Synth Out of Lock)
Control AMP one-shot
16.0 A+ (Current Sense +)
16.0 Current Sense - Voltage Delta 150 mV (30 Watt
only)
9.8
Keyed 9.4-V in
4.5 Current Limit D-A (max current at 4.5 V)
0 0 Ground
9.6 Control AMP Output (Approx 1/2-V Control)
Loop Integrator Capacitor
Control AMP Reference
A+ - CR0500 Drop
VQ0500E - B/E Drop
V pin 23 - B/E Drop
V pin 42 - B/E Drop (TX)
A+ - B/E Drop (TX)
COMMENTS
October 28, 2002
4-33