![Daniels Electronics Ltd. A21-TX3-00 Instruction Manual Download Page 31](http://html1.mh-extra.com/html/daniels-electronics-ltd/a21-tx3-00/a21-tx3-00_instruction-manual_509213031.webp)
DE
DANIELS
ELECTRONICS
VICTORIA B.C.
DE
DANIELS
ELECTRONICS
DWG No: MT3AMTXM9B
TITLE: MT-3 AM Tx AUDIO BOARD SCHEMATIC DIAGRAM
BOARD REV: 04
5.4.2 MT-3 AM Audio Processor Schematic Diagram
MT-3 AM Transmitter Main Board Instruction Manual
JU9
R12, R21
C4, C24
ALC Bypass
BOARD No: 50049-04
TP8
Approx. 200mV rms @ 90% mod.
DWG REV DATE: 19 MAY 98
P4
------
U2
R32
P9
FB1
D2
C25
3.0 KHZ BUTTERWORTH LOW PASS FIILTER
3.0 KHZ BESSEL LOW PASS FILTER
Y
X
Y
X
Y
X
Y
X
Y
X
DATE: MARCH 1998
Automatic Level Control
OPTIONAL
5-9
Automatic Modulation Control
DWN BY: STAN POLYAKOV.
13.8 Vdc
9.5 Vdc
Balanced Input
Mod output
AMC Bypass
Modulation Control
Output Adjust
Balanced Input
Level Adjust
Automatic Modulations
Control Input Adjust
Microphone
Microphone Input
Level Adjust
HIGHEST REFERENCE DESIGNATORS
UNUSED REFERENCE DESIGNATORS
APRVD:
FB1
C1
4.7nF
CW
R1
5K0
TP1
C2
470nF
CW
R4
50K0
TP2
Vcc
Rect In
Var G
Rect Cap
Output
Inv In
R3
THD
Trim
GND
2
3
1
7
5
6
8
13
4
a
U1
SA571D
Rect In
Var G
Rect Cap
Output
Inv In
R3
THD
Trim
15
14
16
10
12
11
9
b
U1
SA571D
R6
100K0
TP3
C3
680nF
C6
100nF
C7
10nF
TP4
680nF
C8
4.7uF
C9
470nF
C10
18K2
R13
CW
R16
5K0
C12
4.7uF
C13
1.0nF
470K0
R18
TP5
TP6
C21
4.7uF
TP8
MT-3 TX TIME-OUT-TIMER
3
P1
2
P5
1
P1
2
P1
3
P2
4
P1
4
P3
4
P5
4
P2
1
P3
8.0V
9.5V
8.0V
-1
P7
-1
P8
-1
P9
-1
P6
-1
J7
-1
J8
-1
J6
-1
J5
D1
1N5221B
D2
1N5221B
R27
681R0
C11
2.2uF
TP7
R5
30K9
2
P3
2
3
4
1
11
a
MC33174
U2
6
5
7
b
MC33174
U2
9
10
8
c
MC33174
U2
8.0V
49K9
R3
49K9
R15
100nF
C14
2.2nF
C16
13
12
14
U2
MC33174
d
R14
100K0
C5
470nF
10K0
R17
4.7nF
C15
51K1
R32
220pF
C18
5K11
R29
5K11
R19
15K4
R24
15K4
R31
51K1
R23
82K5
R28
680pF
C22
220pF
C23
JU5
82K5
R25
JU7
JU8
R20
39K2
R30
47K5
C17
330pF
C25
150pF
R2
20K0
C20
220pF
JU6
R22
3K48
JU4
C19
1.0uF
R9
10K0
R10
27K4
R11
27K4
R26
3M30
JU3
JU9
R8
4K75
R7
1K2
JU2
JU1