Command Set Receiver LIMITED Parts Cross-Reference
(Compiled by Ray Mote 15 January 1996)
This began as an attempt to isolate parts differences between
the SCR-274-N receivers, primarily the capacitors, coils, and
resistors. The objective was to identify common parts which
were interchangeable, as well as those which were not. Once
done, it was natural to expand the listing to the corresponding
Navy Model ARA and the AN/ARC-5 receivers. The lists were
developed using the parts list in each manual, with only
occasional reference to the schematics due to time limitations.
The results are presented below, along with a few of my own
observations.
System .19-.55Mc 3-6Mc 6-9Mc .52-1.5 Mc
SCR-274-N BC-453 BC-454 BC-455 BC-946
ARA 46129 46105 46106 46145
AN/ARC-5 R-23 R-26 R-27 R-24
As you can see, the column sequence above was a result of the
nomenclature sequence in the SCR-274-N series. That is the
layout used for each of the lists below. I did not include the
1.5-3 Mc receivers due to lack of a corresponding receiver in the
SCR-274-N series and page space limitations. Although the SCR-
274-N design derived from the earlier Navy Model ARA, the Air
Corps systems were my primary focus so I placed them first.
Component tolerance, resistor power ratings, capacitor
voltage ratings, etc. have NOT been addressed! (Any volunteers?)
In the SCR-274-N list, I've shown and highlighted in my comments
the differences between individual receivers. In the ARA and
ARC-5 lists, the comments highlight differences between ARC-5
units and the corresponding ARA and SCR-274-N sets. Judicious
use of a "hiliter" pen should lead to lists with parts marked
which can then be used for a detailed analysis of differences
between schematics. Again: Any volunteers?
If you find mistakes, I'd appreciate it if you'd info me so I
can correct my list (as I'm certain you'll correct your own). If
someone wants to use these lists as the starting point for an
article addressing receiver differences in these systems, I'd
*love* to read the result!
-----------------------------------------------------------------
SCR-274-N Receiver Parts Cross-Reference
1. CAPACITORS:
SYMBOL BC-453-A BC-454-A BC-455-A BC-946-B
C1 11 pf 11 pf 8.5 pf 11 pf
C2 15 pf 15 pf 15 pf 15 pf
C3 100 pf 100 pf 100 pf 100 pf
C4A/B/C 346 pf 147 pf 62 pf 346 pf
C4D/E NOT STATED...................................
C4F/G NOT STATED...................................
C5 3 uf 3 uf 3 uf 3 uf
C6A/B/C .05/.05/.05 .05/.05/.05 .05/.05/.05 .05/.05/.05
C7A/B/C .05/.05/.05 .05/.05/.05 .05/.05/.05 .05/.05/.05
C8 200 pf 200 pf 200 pf 200 pf
C9 40 pf 40 pf 40 pf 40 pf
C10 N/A 365 pf 240 pf N/A
C10A/B 690 pf(total)N/A N/A 670 pf(total)
C11 3 pf 3 pf 3 pf 3 pf
C12 180 pf 180 pf 180 pf 180 pf
C13 17 pf 17 pf 17 pf 17 pf
C14 180 pf 180 pf 180 pf 180 pf
C15A/B/C .05/.05/.05 .05/.05/.05 .05/.05/.05 .05/.05/.05
C16A/B/C .22/.22/.22 .22/.22/.22 .22/.22/.22 .22/.22/.22
C17 180 pf 180 pf 180 pf 180 pf
C18 17 pf 17 pf 17 pf 17 pf
C19 180 pf 180 pf 180 pf 180 pf
C20A/B/C .05/.01/.05 .05/.01/.05 .05/.01/.05 .05/.01/.05
C21 17 pf 17 pf 17 pf 17 pf
C22 180 pf 180 pf 180 pf 180 pf
C23 180 pf 180 pf 180 pf 180 pf
C24 200 pf 200 pf 200 pf 200 pf
C25 .001 uf .001 uf .001 uf .001 uf
C26 200 pf 100 pf 100 pf 100 pf
C27 345 pf 180 pf 185 pf 335 pf
C28 34 pf 34 pf 34 pf 34 pf
C29 .006 uf .006 uf .006 uf .006 uf
C30 15 uf 15 uf 15 uf 15 uf
C31 .001 uf .001 uf .001 uf .001 uf
C32 5 uf 5 uf 5 uf 5 uf
C33 3 pf * * *
C34 N/A N/A N/A N/A
C35 750 pf 750 pf 750 pf 750 pf
C36 17 pf 17 pf N/A 17 pf
C37 17 pf 17 pf N/A 17 pf
C38 17 pf 17 pf N/A 17 pf
C39 120 pf N/A N/A N/A
* - Wiring capacitance; less than 2 pf.
Comments:
a. C1 for the BC-455-A is 8.5 pf; the rest are all 11 pf.
b. As expected, C4A, C4B, and C4C vary with tuning range.
Unfortunately, the trimmer caps (C4D,E,F,G) were not
specified.
c. I've shown C10 on two lines, to differentiate between the
single-capacitor and dual-capacitor installations.
d. C26 is 200 pf in the BC-453-A; the rest are 100 pf.
e. C27 is different for each receiver.
f. C33 is 3 pf in the BC-453-A; the rest use the wiring
capacitance (less than 2 pf) instead of an actual capacitor.
g. C36, C37, and C38 are not used in the BC-455-A.
h. C39 is used in the BC-453-A across the primary of the RF Amp
plate coil; it is not used in the others.
2. INDUCTORS:
SYMBOL BC-453-A BC-454-A BC-455-A BC-946-A
L1 NOT STATED...................................
L2/L3 NOT STATED...................................
L4/L5 NOT STATED...................................
L6/L7 NOT STATED...................................
L8/L9 NOT STATED...................................
L10/L11 NOT STATED...................................
L12/L13 NOT STATED...................................
L14 112 uH 112 uH 112 uH 112 uH
L15 3 H 3 H 3 H 3 H
Comments:
Same as ARA and AN/ARC-5 units.
3. RESISTORS:
SYMBOL BC-453-A BC-454-A BC-455-A BC-946-A
R1 620 620 620 620
R2 2 M 2 M 2 M 2 M
R3 51 K 51 K 51 K 51 K
R4 620 620 620 620
R5 150 K 150 K 150 K 150 K
R6 510 K 200 K 150 K 300 K
R7 200 200 200 200
R8 200 200 200 200
R9 620 620 620 620
R10 360 K 360 K 360 K 360 K
R11 100 K 100 K 100 K 100 K
R12 510 510 510 510
R13 200 200 200 200
R14 51 K 100 K 100 K 100 K
R15 20 K 5.1 K 5.1 K 20 K
R16 150 K 51 K 51 K 100 K
R17 150 K 51 K 51 K 100 K
R18 510 K 510 K 510 K 510 K
R19 100 K 100 K 100 K 100 K
R20 2 M 2 M 2 M 2 M
R21 1.5 K 1.5 K 1.5 K 1.5 K
R22 7 K 7 K 7 K 7 K
R23 7 K 7 K 7 K 7 K
R24 N/A N/A N/A N/A
R25 N/A N/A N/A N/A
R26 N/A N/A N/A N/A
R27 N/A N/A N/A N/A
R28 N/A N/A N/A 51 K
(Across RF Amp plate coil in broadcast receiver. This
conflicts with use of "R28" as 50K potentiometer in FT-260)
Comments:
a. R6, R15, R16, and R17 vary with frequency range.
b. R14 is 51K in the BC-453-A and 100K in the others.
c. R28 is only present in the BC-946-A.
BC-xxx-A: T1 (output transformer) is high impedance only.
BC-xxx-B: T1 has both high and low impedance taps; set at
factory for high-z.
BC-xxx-C: ?? (unknown differences)
BC-xxx-D: ?? (unknown differences)
BC-xxx-E: T1 has high/low taps; set at factory for low-z.
-----------------------------------------------------------------
Navy Model ARA Receiver Parts Cross-Reference
1. CAPACITORS:
SYMBOL 46129 46105 46106 46145
C1 11 pf 11 pf 8.5 pf 11 pf
C2 15 pf 15 pf 15 pf 15 pf
C3 100 pf 100 pf 100 pf 100 pf
C4A/B/C 346 pf 147 pf 62 pf 346 pf
C4D/E NOT STATED...................................
C4F/G NOT STATED...................................
C5 3 uf 3 uf 3 uf 3 uf
C6A/B/C .05/.05/.05 .05/.05/.05 .05/.05/.05 .05/.05/.05
C7A/B/C .05/.05/.05 .05/.05/.05 .05/.05/.05 .05/.05/.05
C8 200 pf 200 pf 200 pf 200 pf
C9 40 pf 40 pf 40 pf 40 pf
C10 N/A 365 pf 240 pf N/A
C10A/B 690 pf(total)N/A N/A 670 pf(total)
C11 3 pf 3 pf 3 pf 3 pf
C12 180 pf 180 pf 180 pf 180 pf
C13 17 pf 17 pf 17 pf 17 pf
C14 180 pf 180 pf 180 pf 180 pf
C15A/B/C .05/.05/.05 .05/.05/.05 .05/.05/.05 .05/.05/.05
C16A/B/C .22/.22/.22 .22/.22/.22 .22/.22/.22 .22/.22/.22
C17 180 pf 180 pf 180 pf 180 pf
C18 17 pf 17 pf 17 pf 17 pf
C19 180 pf 180 pf 180 pf 180 pf
C20A/B/C .05/.01/.05 .05/.01/.05 .05/.01/.05 .05/.01/.05
C21 17 pf 17 pf 17 pf 17 pf
C22 180 pf 180 pf 180 pf 180 pf
C23 180 pf 180 pf 180 pf 180 pf
C24 200 pf 200 pf 200 pf 200 pf
C25 .001 uf .001 uf .001 uf .001 uf
C26 200 pf 100 pf 100 pf 100 pf
C27 345 pf 180 pf 180 pf 335 pf
C28 34 pf 34 pf 34 pf 34 pf
C29 .006 uf .006 uf .006 uf .006 uf
C30 15 uf 15 uf 15 uf 15 uf
C31 .001 uf .001 uf .001 uf .001 uf
C32 5 uf 5 uf 5 uf 5 uf
C33 3 pf * * *
C34 N/A N/A N/A N/A
C35 N/A N/A N/A N/A
C36 17 pf 17 pf N/A 17 pf
C37 17 pf 17 pf N/A 17 pf
C38 17 pf 17 pf N/A 17 pf
C39 120 pf N/A N/A N/A
* - Wiring capacitance; less than 2 pf.
C27 is across output winding of CW OSC (inside the can).
Comments:
a. C27 is 180 pf in the 6-9 Mc receiver in ARA, where the SCR-
274-N uses 185 pf in the BC-455.
b. C35 is not present in ARA receivers; it is 750 pf in all SCR-
274-N receivers.
2. INDUCTORS:
SYMBOL 46129 46105 46106 46145
L1 NOT STATED...................................
L2/L3 NOT STATED...................................
L4/L5 NOT STATED...................................
L6/L7 NOT STATED...................................
L8/L9 NOT STATED...................................
L10/L11 NOT STATED...................................
L12/L13 NOT STATED...................................
L14 112 uH 112 uH 112 uH 112 uH
L15 3 H 3 H 3 H 3 H
Comments:
Same as SCR-274-N and AN/ARC-5 units.
3. RESISTORS:
SYMBOL 46129 46105 46106 46145
R1 620 620 620 620
R2 2 M 2 M 2 M 2 M
R3 51 K 51 K 51 K 51 K
R4 620 620 620 620
R5 150 K 150 K 150 K 150 K
R6 510 K 200 K 150 K 300 K
R7 200 200 200 200
R8 200 200 200 200
R9 620 620 620 620
R10 360 K 360 K 360 K 360 K
R11 100 K 100 K 100 K 100 K
R12 510 510 510 510
R13 200 200 200 200
R14 51 K 100 K 100 K 100 K
R15 20 K 5.1 K 5.1 K 20 K
R16 150 K 51 K 51 K 100 K
R17 150 K 51 K 51 K 100 K
R18 510 K 510 K 510 K 510 K
R19 100 K 100 K 100 K 100 K
R20 2 M 2 M 2 M 2 M
R21 1.5 K 1.5 K 1.5 K 1.5 K
R22 7 K 7 K 7 K 7 K
R23 7 K 7 K 7 K 7 K
R24 N/A N/A N/A N/A
R25 N/A N/A N/A N/A
R26 N/A N/A N/A N/A
R27 N/A N/A N/A N/A
R28 N/A N/A N/A 51 K
Comments:
a. Same as SCR-274-N resistors.
-----------------------------------------------------------------
AN/ARC-5 Receiver Parts Cross-Reference
1. CAPACITORS:
SYMBOL R-23 R-26 R-27 R-24
C1 11 pf 11 pf 8.5 pf 11 pf
C2 15 pf 15 pf 15 pf 15 pf
C3 100 pf 100 pf 100 pf 100 pf
C4A/B/C 346 pf 147 pf 62 pf 346 pf
C4D/E NOT STATED...................................
C4F/G NOT STATED...................................
C5 3 uf 3 uf 3 uf 3 uf
C6A/B/C .05/.05/.05 .05/.05/.05 .05/.05/.05 .05/.05/.05
C7A/B/C .05/.05/.05 .05/.05/.05 .05/.05/.05 .05/.05/.05
C8 200 pf 200 pf 200 pf 200 pf
C9 40 pf 40 pf 40 pf 40 pf
C10 N/A 365 pf 240 pf N/A
C10A/B 690 pf(total)N/A N/A 670 pf(total)
C11 3 pf 3 pf 3 pf 3 pf
C12 180 pf 180 pf 180 pf 60 pf
C13 17 pf 17 pf 17 pf 17 pf
C14 180 pf 180 pf 180 pf 180 pf
C15A/B/C .05/.05/.05 .05/.05/.05 .05/.05/.05 .05/.05/.05
C16A/B/C .22/.22/.22 .22/.22/.22 .22/.22/.22 .22/.22/.22
C17 180 pf 180 pf 180 pf 180 pf
C18 17 pf 17 pf 17 pf 17 pf
C19 180 pf 180 pf 180 pf 180 pf
C20A/B/C .05/.01/.05 .05/.01/.05 .05/.01/.05 .05/.01/.05
C21 17 pf 17 pf 17 pf 17 pf
C22 180 pf 180 pf 180 pf 180 pf
C23 180 pf 180 pf 180 pf 180 pf
C24 200 pf 200 pf 200 pf 200 pf
C25 .001 uf .001 uf .001 uf .001 uf
C26 200 pf 100 pf 100 pf 200 pf
C27 345 pf 180 pf 180 pf 335 pf
C28 34 pf 34 pf 34 pf 34 pf
C29 .006 uf .006 uf .006 uf .006 uf
C30 15 uf 15 uf 15 uf 15 uf
C31 .001 uf .001 uf .001 uf .001 uf
C32 5 uf 5 uf 5 uf 5 uf
C33 * * * *
C34 N/A N/A N/A N/A
C35 100 pf 100 pf 100 pf 100 pf
C36 17 pf 17 pf N/A 17 pf
C37 17 pf 17 pf N/A 17 pf
C38 17 pf 17 pf N/A 17 pf
C39 N/A N/A N/A 120 pf
C40 100 pf 100 pf 100 pf 100 pf
C41 100 pf 100 pf 100 pf 100 pf
C43 N/A 3 pf 2 pf N/A
* - Wiring capacitance; less than 2 pf.
Comments:
a. C10 (single or dual) went from mica to ceramic capacitors in
January of 1945.
b. C12 is 60 pf in the R-24; all other systems used 180 pf.
c. C26 is 200 pf in the R-24, but 100 pf in the other systems.
d. C27 is 180 pf in the R-24 and 46106, but 185 pf in the BC-
455.
e. C33 uses wiring capacitance in the R-23 where real caps are
used in the BC-453 and 46129.
f. C35 is 100 pf in the ARC-5 receivers, omitted in ARA, and 750
pf in the SCR-274-N receivers.
g. C39 is omitted in the R-23 (present in 46129 and BC-453) and
inserted in the R-24 (omitted in 46145 and BC-946).
h. C40, C41, and C43 are all present in the ARC-5, but not in
ARA or SCR-274-N.
2. INDUCTORS:
SYMBOL R-23 R-26 R-27 R-24
L1 NOT STATED...................................
L2/L3 NOT STATED...................................
L4/L5 NOT STATED...................................
L6/L7 NOT STATED...................................
L8/L9 NOT STATED...................................
L10/L11 NOT STATED...................................
L12/L13 NOT STATED...................................
L14 112 uH 112 uH 112 uH 112 uH
L15 3 H 3 H 3 H 3 H
Comments:
Same as SCR-274-N and ARA units.
3. RESISTORS:
SYMBOL R-23 R-26 R-27 R-24
R1 1 K 620 620 620
R2 2 M 2 M 2 M 2 M
R3 51 K 51 K 51 K 51 K
R4 620 620 620 620
R5 510 K 510 K 510 K 510 K
R6 510 K 200 K 150 K 300 K
R7 200 200 200 200
R8 200 200 200 200
R9 1 K 620 620 620
R10 360 K 360 K 360 K 360 K
R11 510 K 10 K 10 K 510 K
R12 390 390 390 390
R13 2 M 510 K 510 K 510 K
R14 100 K 100 K 100 K 100 K
R15 20 K 5.1 K 5.1 K 20 K
R16 300 K 51 K 51 K 300 K
R17 N/A 51 K 51 K 100 K
R18 510 K 510 K 510 K 510 K
R19 150 K 100 K 100 K 150 K
R20 2 M 2 M 2 M 2 M
R21 1.5 K 1.5 K 1.5 K 1.5 K
R22 7 K 7 K 7 K 7 K
R23 7 K 7 K 7 K 7 K
R24 3 K 3 K 3 K 3 K
R25 N/A N/A N/A N/A
R26 150 K N/A N/A 150 K
R27 100 K N/A N/A 100 K
R28 1 K* N/A N/A 1 K*
R29 N/A 2.4 K 2.4 K N/A
R30 N/A 100 K 100 K N/A
R31 N/A 100 K 100 K N/A
R32/33/34 N/A N/A N/A N/A
R35 N/A N/A N/A 51 K
R36 N/A N/A N/A N/A
R37 200 200 200 200
* - R28 in early production units only.
Comments:
a. R1 is 1K in the R-23, but 620 ohms in 46129 and BC-453.
b. R5 is 510K in ARC-5, but 150K in ARA and SCR-274-N.
c. R9 is 1K in R-23, but 620 ohms in 46129 and BC-453.
d. R11, R12, and R13 are radically different in ARC-5.
e. R14 is 100K in R-23, but 51K in 46129 and BC-453.
f. R16 is 300K in R-23, but 150K in 46129 and BC-453.
g. R17 is omitted (?) in R-23 but present in 46129 and BC-453.
h. R19 is 150K in R-23, but 100K in 46129 and BC-453.
i. R24 is 3K in ARC-5, but omitted in ARA and SCR-274-N.
j. R26 and R27 are only present in ARC-5 receivers.
k. R28 is 51K in ARA and SCR-274-N broadcast receivers, but
appears as 100K in R-23 and R-24 early production units only.
l. R29, R30, R31, R35, and R37 are found only in ARC-5 units.