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November 24, 2003
HKLN4216A
5-10
VHF Troubleshooting Tables:
Troubleshooting Table for Board and IC Signals
U251
VCO / Buffer
12
Prescaler output
2.26
13
TX switch output (NU)
0.06
14
Vcc_BUFFERS
3.00
15
TX VCO emitter
0
(RX mode)
16
TX VCO base
0
(RX mode)
17
GND_LOGIC
GND
18
Vcc_LOGIC
3.00
19
TRB input
0.03
From U201-2 (RX mode)
20
FLIP input
GND
U310
5 V Regulator
1
Vin
7.48
2
Ground
GND
3
Control input
7.48
4
Bypass capacitor
1.26
5
Vout
4.96
U320
3.3 V Regulator
1
Ground
GND
2
Feedback
1.23
3
Tap (NU)
0
4
Vin
7.48
5
Vout
3.23
6
Sense (NU)
0
7
Error (reset output)
3.20
8
Shutdown input
7.48
U330
3 V Regulator
1
Vin
7.48
2
Ground
GND
3
Control input
7.48
4
Bypass capacitor
1.26
5
Vout
3.00
U401
Microprocessor
1
PD4_SCK serial clock input
0
2
PD5_SS
3.23
ASFIC chip select
3
PD6_VLIN
3.23
EEPROM chip select
4
PG7_R_W
3.21
5
PG6_AS
3.23
6
PG0_XA13
3.23
7
PB7_ADDR15
0.026
8
PB6_ADDR14
0.028
9
PB3_ADDR11
3.06
Table 5-4. Troubleshooting Table for Board and IC Signals (Continued)
IC Designator
Pin
Pin Function
DC Voltage
Comments (Condition)
Summary of Contents for EP450
Page 31: ...November 24 2003 HKLN4216A 4 8 VHF Theory Of Operation Keypad Notes ...
Page 77: ...November 24 2003 HKLN4216A Notes 7 8 403 440 MHz UHF Theory Of Operation Keypad ...
Page 85: ...November 24 2003 HKLN4216A Notes 8 8 438 470 MHz UHF Theory Of Operation Keypad ...
Page 93: ...November 24 2003 HKLN4216A Notes 9 8 465 495 MHz UHF Theory Of Operation Keypad ...