Power Module Installation Method; Terminal Function - Kenwood TH-28A Service Manual

TH-28A/E
POWER MODULE INSTALLATION METHOD
Install the power module and RF unit as shown in
Figure 1. When the power module ts replaced follow-
ing repair, use the procedure below to maintain dimen-
sions *1 and *2.
Do not bend the ground spacer when removing
the power module, and do not use power module
with a bent ground spacer.
1. Insert the power module into the RF unit, and place
it on the rear part of the case without soldering any
wires or securing it with screws.
2. Pressing the power module from above with your
fingers to prevent it lifting, temporarily secure the
Power module
»
Power module read
*16 2
RF unit
"
_
4
}
| MUBEEERBEEB EE SEEBREREEEE
*2 9.2
2 +
GND spacer
Fig. 1
~~power module leads at two points by soldering from
_ the component side of the RF unit. (Fig. 2)
3. Stand the RF unit upright, and solder the five leads
properly from the soldered side. (Fig. 3)
Fix the RF unit to the rear part of the case with
SCrews.
— 43
TH-28A/E
TERMINAL FUNCTION
Terminal Function
Connector Connector |Terminal! Terminal Terminal] Terminal Terminal Function
No. No. Name No. No. Name
TX-RX UNIT (B/2) : RF © TX-RX UNIT (A/2) : IF | 3 IM Microphone signal
1 MOD | Modulation input 4 Cl Signaling AF output
2 cP Clock signal
5 SM
S-meter control power supply
83 DP | Data signal | 6 BEEP | Beep signal
4 EP | Enable signal {| 7 | BUSY | Busy signal
5° UL PLL unlock signal | 8 DN Encoder down signal
6 TX | VCO switching signal ~| & | MUTE | Audio mute signal
7 5C 5V power supply | 10 CTSW | Tone control signal
g APC | APC voltage input 1 UP | Encoder up signal
9 EL EL power switching signal 12 PTT | PTT switch signal
10 FBO | Power supply 13 TO Tone signal |
11 5T | Transmit 5V power supply 14 E Ground
12 BSW | Receive BPF switching power supply 15 REM Remote controller microphone signal
13 BRS UHF receive power supply 16 BSW | Receive BPF switching power supply
14 5RM | VHF receive power supply 7 SMH Microphone 5V power supply |
15 5R36 | 360MHz band receive power supply 18 EL EL power switching signal
16 NC 19 TX VCO switching signal
17 5M Microphone 5V power supply 20 UL PLL unlock signal
18 MIC | Microphone signal 21 EP | Enable signal
19 IM Internal microphone signal
22 CP
Clock signal
20 SP-—|Internal'speaker signal 23 ESW___|EL power control signal
94 AFO Audio output | 24 5BMSW | Microphone 5V
22 PTT | PTT switch signal 25 7; DP | Data signal, a
23 REM | Remote controller microphone signal 26 SDO | Tone signal identification signal
24 E Ground | | 27 ET Tone enable signal
25 AE — | Audio line ground 28 B | Power supply a
26 IFO IF signal | (2 AFC | Audio amplifier power supply control signal
CONTROL UNIT (A/5) : CONTROL <> ME-1 (Option) 30 5TS Transmit 5V power supply control signal |
CONTROL UNIT (A/5) : CONTROL <> KEYBOARD FPC
CN1 1 E Ground :
2 SBM BV power supply 1 TK4 Key matrix input
3 16CL | Clock signal 2 TK2 Key matrix input
4 NC 3 TK3 Key matrix input
5 DIO Serial data 4 TK4 Key matrix input
= 6 TKE Key matrix output
CN3 1 TO Tone signal output 4 TKI Key matrix output
2 E Ground 8 TK8 Key matrix output
3 SDO Tone signal match/mismatch identifi- |g "KO Key matrix output
pation signal CONTROL UNIT (A/5) : CONTROL © PTT UNIT
4 Cl Signaling AF output
5 'a> Clock signal 1 PTT PTT switch signal. "L": TX, "H": RX
6 5C 5V power supply 2 FLOCK | Lock switch signal
7 DP Tone serial data 3 COM | Key matrix output
8 | TXO | Modulation input 4 | MONI | Key matrix input. MONI SW
2 ET__{ Tone enable 5 | LAMP | Key matrix input. LAMP SW
TX-RX UNIT (A/2} : IF < CONTROL UNIT (A/5) : CONTROL 6 FE Ground
CN1 1 AE Audio ground
2 SP
Internal speaker signal
44