©2003 Hamtronics, Inc.; Hilton NY; USA. All rights reserved. Hamtronics is a registered trademark. Revised: 10/2/07
- Page 2 -
the original frequencies. All the fre-
quencies still have the same relation-
ship to each other in the new spec-
trum.
As an example, use the CC144
Converter frequency scheme. To lis-
ten to 144.000 MHz, you would tune
your receiver to 28.000 MHz. To
hear 144.100 MHz, tune to 28.100;
to hear 144.105, tune to 28.105, etc.
TROUBLESHOOTING.
The usual troubleshooting tech-
niques of checking dc voltages at
transistor elements and tracing oscil-
lator injection signals with an rf
probe and voltmeter are appropriate
for this converter.
Current drain is typically about
10-20mA; this is a very good indica-
tion of any problems on the B+ line.
If no voltage is measured at TP1,
the emitter of the multiplier stage,
that is an indication that the rf level
from the oscillator is too low to drive
the base of the transistor into con-
duction.
Probably the most common trou-
bles, based on our experience, is
blown transistors or voltage regulator
ic due to reverse polarity or tran-
sients on the B+ line. Any relay coils
connected across the B+ line should
have a reverse diode connected di-
rectly across the relay coil to absorb
the reverse transient produced when
the relay is unkeyed.
Typical Dc Voltages.
Following are positive dc voltages
with respect to ground, measured
with an fet voltmeter on a sample
unit operating on 13.6Vdc. While
readings can vary widely without
necessarily indicating trouble, these
readings can be used in conjunction
with an organized troubleshooting
plan to help isolate the trouble.
XSTR E(S)
B(G1)
G2
C(D)
Q1
0
0
3.3
6.7
Q2
0
0
0
7.1
Q3
1.5
2.2
-
7.0
Q4
1.5
0
-
7.3
PARTS LIST FOR CC144,
CC145, CC146.
Ref Desig Value
C1
27pf
C2
56pf
C3-C4
.001µf
C5
18pf
C6
0.5pf
C7
18pf
C8
.001µf
C9
.01µf
C10
47pf
C11
4pf
C12
62pf
C13
220pf
C14
.001µf
C15
20pf red variable cap
C16
27pf
C17-C18 150pf
C19
.001µf
C20
68pf
C21
1pf
C22
62pf
C23-C24 .001µf
C25
27pf
C26
0.5pf
C27
27pf
C28
0.1µf
C29
100µf electrolytic
C30-C31 .001µf
J1-J2
RCA jacks
L1
0.33µH rf choke
L2-L4
2½ turn (red) coil
L5-L6
14½ turn (yel) coil
L7-L8
6½ turn (blu) coil
L9-L10
2½ turn (red) coil
Q1-Q2
BF-998 f.e.t.
Q3-Q4
MSC3130 rf xstr
R1
100K
R2
not used
R3-R4
100K
R5
10K
R6
22K
R7
1K
R8
680
Ω
R9
100
Ω
R10-R11 47
Ω
R12-R14 100
Ω
U1-U5
not assigned
U6
78L08
Y1
Crystal (see chart)
PARTS WHICH DIFFER FOR
CC50 CONVERTER.
Ref Desig Value
C1
82pf
C2
220pf
C5
56pf
C6
1pf
C7
62pf
C14
n/u
C20
82pf
C21
1pf
C22
82pf
L1
15µH choke
L2-L4
6½ turn coils
L7-L8
14½ turn coils
Y1
22.000 MHz
Note: The following
parts are not used:
Q4, C24-C27, L9-
L10, R7, R14. In-
stead, a jumper wire
must be tack sol-
dered to the bottom
of the board along
the path from what
normally is the base of Q4 down
through C25 and C26, with a dog leg
to cover both pads of C26 as shown
here.
PARTS WHICH DIFFER FOR
CC222 CONVERTER.
Ref Desig Value
C1
5pf
C2
not used
C5
6pf
C6
not used
C7
5pf
C20
39pf
C21
0.5pf
C22
39pf
C25
5pf
C26
not used
C27
7pf
Y1
21.5556 MHz