Kenwood TK-3401D Service Manual page 10

2.3.7 Power Supply
There are five 5V power supplies and five 3.3V power supplies: 50M, 50V, 50C, 50R, 50T, 33M, 33MS, 33B, 33R and 33MD.
50M and 33M are always output while the power is on.
33MS is always output, but turns off when the power is turned off, to prevent a malfunction of the MCU.
50C is a common 5V and is output when SAVE is not set to ON.
50R is 5V for reception and is output during reception.
50T is 5V for transmission and is output during transmission.
50V is 5V for the SP/MIC connector.
33B is 3.3V for the baseband IC (IC705).
3R is 3.3V for the IF IC (IC400) and is sent when SAVE is not set to ON.
33MD is 3.3V for the MCU digital supply.
BATT
GND
2.3.8 dPMR Receiving
2.3.8.1 For Digital Data Mode
The demodulated signal from IC400 (Pin13) is fed into the baseband IC (Pin 16) for dPMR decoding. The decoded digital data will
pass to the MCU through the C-BUS. The MCU determines whether or not to output sound from the speaker by checking if the data
matches.
1-10 (No.RA012<Rev.001>)
F600
2.5A
F601
1A
SB
IC710
MCU
5CC
50TC
BATT
50RC
INT
VDDA
RESET
VDD1-VDD6 33MSC
Fig.8 Power supply
IC703
AVR
IC603
AVR
IC602
AVR
IC601
AVR
IC600 IC604
DET AVR
IC605
DET
+B
33B
50V
SB
50C
IC606
33R
AVR
50M
Q601
50T
50T SW
Q602
50R
50R SW
IC715
33MD
AVR
33M
Q606
33MS
33MS SW