5
Assembly
Start by soldering the switch onto PCB 2 and the panel-
mount connector for the headset onto PCB 4 (apply solder
sparingly). Then remove these two PCBs from the PCB
panel and file the tabs off.
Next, fit the following components on PCB 3 using the previously
described soldering method:
1. C3 (10 µF; no marking, large SMD)
2. R1 & R4 (100 kΩ; marking
1003
)
3. R2 & R3 (100 kΩ; marking
1002
)
4. R5 (1 kΩ; marking
1001
)
5. C1 (10 nF; no marking, small SMD)
6. T1 (BSR17; marking
U92
)
7. T2 & T3 (BC847, marking
1FW
)
Now check the circuit for proper operation before
continuing with assembly. This is important because any
mistakes at this stage will be very difficult or impossible
to correct later on.
Temporarily connect a 1.5 V supply voltage to the points indicated below.
1
2
3
5
4
6
