Kenwood TM-221A Service Manual page 13

SQL (X59-3150-00)
a ee eee
} ai Noise amplifier
Squelch switching
DC amplifier OFF when squelch is on.
Low-frequency amplifier For RD terminal
Tcowstraciuancy amplifier OFF when squelch is.on.
awe EO when squelch is on.
Squelch noise rectifier
Base bias setting
MIC (X59-3160-00)
1C1(1/2) | Low-frequency amplifier @ Output, @ Input.
Low-frequency amplifier For microphone check. © Input @ Output.
102(1/2) | Limiting amplifier @ Output @ Input.
1C2(2/2) | LPF ® .@ Output.
VOL (X59-3170-00)
Function Description
Output.
Input.
Initialize input : '"L'' > step 6.
Increase (''L."' input raises the volume 1 step).
Decrease (''L'' input lowers the volume 1 step).
"H"' while operating.
controlled by (3)
controlled by ©)
controlled by ©
controlled by @
Bidirectional switch enable ON to enable electronic volume control.
Electronic volume control
(16 steps, initialized to the
6th step from the
bottom)
Bidirectional switch (4 circuits)
ORO RS IRC RORO RS)
ON to decrease by 7 step.
Switching ; ON to increase by 1 step.
Voltage drop
15