Service manual

B.2 TP0332/2
Loudspeaker
Impedance 16Ω ±2Ω.
Power rating 0,3W nominal, 0,5W maximum.
Headset socket 3,5mm - loudspeaker disconnected when jack
inserted.
Environmental
Operating temperature range –20°C to +55°C.
Storage temperature range –40°C to +80°C.
Figure B.2 Lapel Speaker / Microphone Circuit Diagram
OPERATION
Ancillary Type
R3 defines the ancillary as a Lapel Speaker / Microphone.
Microphone
The microphone connects to the radio via the tip of the 2,5mm stereo jack (J1) and is powered via
the ring and sleeve of the 3,5mm stereo jack (J2) on the cord assembly.
When the Lapel Speaker / Microphone is connected to the radio, the radio’s microphone is switched
out of circuit.
Operation of the PTT switch brings into circuit the electret microphone, which is powered from a
rectified and filtered DC supply from the radio. R5 is used to generate a PTT interrupt to the radio.
Speech is superimposed onto this voltage on using the microphone with the PTT switch pressed.
Loudspeaker
The loudspeaker connects to the radio via the ring and sleeve of the 2,5mm stereo jack (J1) on the
cord assembly.
When the Lapel Speaker / Microphone is connected to the radio, receive audio is routed to the
ancillary loudspeaker and not to the radio’s.
The Lapel Speaker / Microphone supports the use of a remote headset.
–
+
Headset Jack
J2 (3,5mm)
J1 (2,5mm)
R4
R5
Mic
R1
C1
22µF
R3
Schottky
C5
Mylar
Loudspeaker
1µF
2k2
M–
M+
red
black
white
24k
Diode
Schottky
Diode
D
S
G
T1 BS170
2k4
1k
C2
1µF
R2
1M
(2,5mm)
black
yellow
red
shield
PCB
PTT
Switch
BAT545W
BAT545W
C4
100p
160
Ω
0,3W
C3
100n