4-1
Chapter 4 Schematic Diagrams, Overlays, and Part
Lists
4.1 Introduction
This chapter provides schematic diagrams, overlays, and parts lists for the radio circuit board and
interface connections.
4.1.1 Notes For All Schematics and Circuit Boards
* Component is frequency sensitive. Refer to the Electrical Parts List for value and usage.
1. Unless otherwise stated, resistances are in Ohms (k = 1000), and capacitances are in picofarads
(pF) or microfarads (µF).
2. DC voltages are measured from point indicated to chassis ground using a Motorola DC multime-
ter or equivalent. Transmitter measurements should be made with a 1.2 µH choke in series with
the voltage probe to prevent circuit loading.
3. Reference Designators are assigned in the following manner:
100 Series = Transmitter UHF
200 Series = Frequency Generation UHF
300 Series = Receiver UHF
400/500 Series = Controller
600 Series = Keypad Board
3200 Series = IF Circuitry
3300 Series = Receiver VHF
3500 Series = Transmitter VHF
3700/3800 Series = Frequency Generation VHF
4. Interconnect Tie Point Legend:
UNSWB+ = Unswitch Battery Voltage (7.5V)
SWB+ = Switch Battery Voltage (7.5V)
R5 = Receiver Five Volts
CLK = Clock
Vdda = Regulated 3.3 Volts (for analog)
Vddd = Regulated 3.3 Volts (for digital)
CSX = Chip Select Line (not for LVZIF)
SYN = Synthesizer
DACRX = Digital to Analog Voltage (For Receiver Front End Filter)
VSF = Voltage Super Filtered (5 volts)
VR = Voltage Regulator
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