©2009 Hamtronics, Inc.; Hilton NY; USA. All rights reserved. Hamtronics is a registered trademark. Revised: 8/10/11
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Table 3. Typical Test Point Voltages
TP1 Tuning V.
Normally set at +2Vdc
TP2 Inj. Level
+0.25Vdc
TP3 Sig. Level Varies from -0.5Vdc to
+0.9Vdc depending on
noise quieting with signal.
TP4 Freq.
Varies with frequency of
input signal. Voltage at
this point normally is ad-
justed for +2.0Vdc with a
signal exactly on fre-
quency. Can vary a little
without being a problem.
Table 4. Typical Xstr DC Voltages
Xstr Stage
E(S) B(
G1) C(D) G2
Q1 dc filter
4.0
4.7
4.8 -
Q2
vco
0.95 1.6
3.8
-
Q3 doubler
0
0.68
2.6
-
Q4
buffer
0
0.74
2.7
-
Q5
RF ampl
0
0
4.8
2.4
Q6
Mixer
0.25 0
5
1.0
Q7
sq. open
0
0
5
-
sq. closed
0
0.65
0.15 -
Table 5. Typical IC DC Voltages
U2-1 2.3
U2-7
5
U2-2 2.1
U2-8
1.7
U2-3 5
U2-9
0
U2-4 5
U2-10
0
U2-5 0 - 4.5
U2-11
0
U4-1: 5
U4-10: 0.8
U4-2: 4.5
U4-11: 2
U4-3: 4.8
U4-12: 0.5 (with
U4-4: 5
sq. just closed)
U4-5: 3.8
U4-13:
U4-6: 3.8
0V (sq. open),
U4-7: 3.8
5V (sq. closed)
U4-8: 5
U4-14: 0
U4-9: 2 (Varies
U4-15: 0
w/ freq.)
U4-16: 1.8
U5-1: 1.4
U5-6: 13.6
U5-3: 0
U5-7:
7
U5-5: 6
U5-8:
1.4
Table 6. Typical Synthesizer Levels
Data signals from microcontroller U1:
Latch enable (LE), clock, and data signals
are constant stream of 5V pulses which can
be observed with scope set for dc input with
1mSec/div horizontal scan.
U3 TCXO output is approx sine wave signal
of 2.5V p-p.
PARTS LIST FOR R306 UHF
FM RECEIVER.
Caution: static sensitive part. Use ap-
propriate handling precautions to avoid dam-
age.
Ref Desig
Value (marking)
C1
0.1µf
C2
2pf
C3
100pf
C4
0.1µf
C5
100µf electrolytic
C6
0.15µf mylar (red)
C7
.01µf
C8
.001µf
C9,C10
100µf electrolytic
C11
0.1µf
C12
390pf
C13
5pf
C14
390pf
C15
100µf electrolytic
C16
12pf
C17
47pf
C18
7pf
C19
220pf
C20
100pf
C21
4.5pf variable (white)
C22
2pf
C23
100pf
C24 **
4.5pf variable (white)
C25
220pf
C26
5pf
C27,C28
100pf
C29 **
4.5pf variable (white)
C30
4.5pf variable (white)
C31 **
4.5pf variable (white)
C32 **
4.5pf variable (white)
C33
4.5pf variable (white)
C34
.0047µf
C35-C37
.001µf
C38
7pf
C39
4pf
C40
7pf
C41
.001µf
C42
0.47µf electrolytic
C43
0.1µf
C44,C45
.001µf
C46,C47
.01µf
C48
0.1µf
C49
10µf electrolytic
C50
220µf electrolytic
C51
0.1µf
C52
68pf
C53
220pf
C54-C56
0.1µf
C57
100µf electrolytic
C58
1µf electrolytic
D1
BB132 varactor diode
D2,D3
MMBT3904 used as diode
FL1-FL4
10.7MHz crystal filter
(matched set of 4)
FL5
455kHz ceramic filter
J1
RCA Jack
J2
6-pin header
L1
1½ turn slug-tuned (brn)
L2
0.22µH RF choke
(red-sil-red-red)
L3,L4
2¾ turn air wound coil
L5
3¾ turn air wound coil
L6
4¾ turn air wound coil
L7,L8
2¾ turn air wound coil
L9
4¾ turn air wound coil
L10
2¾ turn air wound coil
Q1
MMBT3904
Q2-Q4
MSC3130
Q5,Q6
BF998 dual gate mos fet
(note: source is wide lead)
Q7
MMBT3904
R1
27
Ω
R2
15K
R3
150K
R4
10K
R5
1K
R6,R7
27
Ω
R8,R9
10K
R10
180
Ω
R11
27
Ω
R12
10K
R13
3.9K
R14
470
Ω
R15
47
Ω
R16
470
Ω
R17
10K
R18
3.9K
R19,R20
100K
R21
27
Ω
R22
2.2K
R23
330K
R24
22K
R25
27
Ω
R26
47
Ω
R27
270
Ω
R28
330K
R29
15K
R30
2 MEG
R31
47K
R32
100K pot
R33
68K
R34
100K
R35
510K
R36
4.7K
R37
680
Ω
R38
1K
R39
22K
R40
100K
R41
100K pot
R42
47K
R43
10
Ω
T1,T2
10.7MHz IF xfmr
(T1005)
T3
455kHz IF transformer
(T1003)
U1
MC9RS08KA1 µP
U2
LMX1501A
U3
10.240MHz TCXO
U4
MC3361BP (smt type)
U5
LM386N-1
U6
78L05 regulator (smt type)
XU1
8 pin ic socket
Y1
10.245 MHz crystal
** Note: C24, C29, C31, and C32 each
have 1pf capacitor tack soldered across pads
on rear of board.
