Parts List for SC-50DW Squelch and CTCSS boards:
All board versions are functionally equivalent.

U1 - 78L09
U2 - SC6709 or M7716 (Motorola squelch chip - available optionally)
U3 - 78L05
U4 - MX465DW (CML) (pre-installed)
16 pin dual-wipe DIP socket for U2

Q1 - 2N2222 
Q2 - 2N2222
Q3 - 2N2222
Q4 - 2N2907
Q5 - 2N2907
Q6 - 2N2222

(4 - 2N2222, 2 - 2N2907)


D1 - 1N4004
D2 - 1N4148
D3 - 1N4148

(1 - 1N4004 - 2 - 1N4148)


D4 - LED - Green
D5 - LED - Blue
D6 - LED - Red

R1 - 15 ohm
R2 - 27k
R3 - 180k - mounts vertically
R4 - 4.7k
R5 - 10k
R6 - 1k  - mounts vertically
R7 - 220 ohm
R8 - 100 ohm
R9 - 4.7k
R10 - 10k
R11 - 4.7k
R12 - 1k
R13 - 680 ohm
R14 - 100 ohm
R15 - 10k
R16 - 10k
R17 - 560k
R18 - 820k
R19 - 22k
R20 - 10k Pot
R21 - 1 Meg
R22 - 4.7k
R23 - 4.7k
R24 - 1k
R25 - 1k
R26 - 1k  - mounts vertically
R27 - 10k

RD - 22k - User supplied - mounts vertically
RX - User determined - User supplied - mounts vertically


(5-10k,  5-1k,  5-4.7k, 2-100 ohm)


X1 - 4.000 MHz Crystal with Plastic Spacer

S1 - 6 position DIP switch

SJ1-2 - 3 position header (green)  with short (might be blue)
SJ3-4 - 3 position header (yellow) with short
SJ5  -  2 position header (white)  with short

C1 - .47 uF (474)
C2 - .1 uF  (104)
C3 - 4.7 uF Electrolytic
C4 - .1 uF  (104)
C5 - 22 uF Electrolytic
C6 - 4.7 uF Electrolytic
C7 - .001 uF (green)
C8 - 100 pF SM
C9 - 470 pF SM
C10 - .01 uF
C11 - .22 uF
C12 - 3.3 uF Electrolytic
C13 - 2.2 uF Electrolytic
C14 - .47 uF (474)
C15 - 4.7 uF Electrolytic
C16 - .1 uF  (104)
C17 - .47 uF (474)
C18 - 18 pF SM
C19 - 33 pF SM
C20 - .12 uF
C21 - .12 uF
C22 - .12 uF
C23 - .47 uF (474)
C24 - .12 uF
C25 - .12 uF
C26 - .12 uF
C27 - .22 uF
C28 - .15 uF
C29 - 750 pF SM 300V
C30 - 100 pF SM
C31 - 47 pF ceramic
C32 - 47 pF ceramic
C33 - 47 pF ceramic
C34 - 47 pF ceramic
C35 - 47 pF ceramic


(4-.47uF,  6-.12uF,  3-4.7uF, 2-100pF SM,  2-.22uF, 3-.1uF  5-47pF)

DB25 Female chassis connector

Masters Communications SC-50DW Squelch-CTCSS circuit board - Blue  (current revision)