Motorola EP450 Service Manual page 39

5-8
Table 5-4. Troubleshooting Table for Board and IC Signals (Continued)
IC Designator Pin
U110
RF Power Amp
U150
Dual Opamp
U201
Freq Synthesizer
November 24, 2003
VHF Troubleshooting Tables: Troubleshooting Table for Board and IC Signals
Pin Function
1 RF input
2 Vgg (gate bias)
3 Vdd
4 RF output
5 Ground
1 Unit 1 output
2 Unit 1 (-) input
3 Unit 1 (+) input
4 Ground
5 Unit 2 (+) input
6 Unit 2 (-) input
7 Unit 2 output
8 Vcc
1 AUX2 output (NU)
2 AUX3 output (TRB)
3 AUX4 output (NU)
4 Lock detect output
5 PD Vdd
6 Digital ground
7 Serial data input
8 Serial clock input
9 Synth chip select
10 Modulation input
11 VMULT4 (NU)
12 VMULT3 (NU)
13 VRO
14 VMULT2
15 VMULT1
16 INDMULT (NU)
17 NC1
18 Ref select (NU)
19 Buffered 16.8 MHz out
20 Analog Vdd
21 V bypass (NU)
22 Analog ground
23 Ref osc XTAL1
DC Voltage Comments (Condition)
0 (TX mode)
2.65 (typ) (TX mode) (4.25 V typ at VHF)
6.59 (TX mode)
-- Do not measure
GND
4.20 (typ) (TX mode) (5.8 V typ at VHF)
2.39 (typ) (TX mode)
2.39 (typ) (TX mode)
GND
3.30 (typ) (TX mode)
3.35 (typ) (TX mode)
2.23 (typ) (TX mode)
6.79 (TX mode)
0
0.03 To U251-19 (RX mode)
0
2.98 To U401-56
2.98
GND
3.23
0
3.23 From U401-47
1.50 From U451-40
2.98
0
4.96
1.49
1.49
0
0
0
1.54
3.00
1.55
GND
2.07
HKLN4216A