ARC Recievers General Notes User Guide

A

USERS GUIDE

TO

AIRCRAFT RADIO

CORPORATION

RECEIVERS

by

M. W. Tauson

One of the neat things about the military is the rather vast quantities in which it produces
surplus for people like us to pick up in equally vast quantities. This process has most likely
been going on since Ceasar's time (although I suspect the market has probably changed a bit)
and will continue as long as there are militaries to have surplus.

Probably the one group of radio equipment to hit the market more heavily than any other is
that known as the Command sets. These units (specifically the ATA/ARA, SCR-274N, and
ARC-5 sets) were released as surplus after World War II and are still showing up in new,
unused condition some 35 years later. They have been converted from mild to wild and are
responsible for getting quite a few people on the air who could not have otherwise afforded a
rig, myself included.

The original design that started this avalanche came from Aircraft Radio Corporation. There
were three major builders, A.P.C., Stromberg-Carlson who built most of the early ATA/ARA
sets as well as some of the ARC-5's and later Type 12's, and Western Electric who built most
of the SCR-274N's (Navy rigs with Army markings essentially) plus the VHF Command sets.
There were other suppliers but not any that produced the quantities that these did.

As a general rule, SCR-274N and ATA/ABA equipment may be mixed freely. ARC-5
receivers may be used with the other two series, as may the racks, control boxes, etc. ARC-5
transmitters, modulators, racks and control boxes for the transmitters will not mate with their
counterparts due to connector differences. It is interesting to note that the various receivers
would also fit the SCR-274N and ATA transmitter racks which probably lead to the early (if
not smelly) demise of a few receivers, and played a part in the design change for the ARC-5
transmitter rack.

The A.R.C. type 15 receivers will fit the Command set racks however the pin assignments are
different necessitating some re- wiring. The Type 12 receivers and the TV-10 transverter also
fits however there is no rear connector on them nor is there any method to lock them in place.
The modifications are very simple however and it does make for a convenient way to mount
the unite.

The various control boxes are useful not only for controlling 'in type' equipment but also for
other pieces.

The information on the following pages is from tech manuals, schematics and in some cases
from the units themselves. There are no schematics- these are available from such sources as
the nice people at Fair Radio Sales. What is here is some very basic info on 'What is it?' and
'How do I make it work?'. There are equipment lists, pinots, some VERY brief specs,
connector lists, and a few quick hook-ups so you can light off the rig without too much fuss
and bother.

Some pieces not in the Command and Type 12 series are included, and some that are parts of
the various series are not here. The criteria for these two groups was availability- the former
are generally available and the latter aren't.

Where possible, included the A.R.C. part number for the various units, which provides a
ready made cross-reference between the series. There are at the end a series of lists in numeric
order to assist in this referencing.

The ATA/ARA and some pieces of the ARC-5 sets are identified by a five digit number. This
is the numeric portion of the Navy accounting number of the item. The Navy accounting
system is a method of uniquely identifying equipment and consists of a three letter and five
digit code. The three letters (the first of which is always 'C') identifies the builder, with CBY
(A.R.C.) and CCT (Stromberg-Carlson) being the ones most commonly found on the
Command set units. The first two digits of the numeric portion identify the type of unit (46 for
receivers, 52 for transmitters, etc with related pieces carrying the same type identifier) and the
last three digits uniquely identify the particular unit. Note that a CBY-46104 receiver and a
CCT-46104, for example, are the same receiver built by two different builders. For this
reason, the builder code has been deleted from the following lists.

The builder code does appear on some, if not all, ARC-5 units on the identification plate after
the serial number. On the other series, the builder's name often is on the identification plate at
the bottom.

At some point or another, I hope to have an addendum covering items missed plus any added
information that may be of use. Any assistance toward this end will be gratefully accepted,
and will be acknowledged in the addendum. In the mean time, however, I would like to thank
George Sellout at Fair Radio for his help (and for being tolerant of me!), Gordon Eliot White
for getting me interested in A.R.C. through his many fine articles, and, of course, the Aircraft
Radio Corporation for their excellent products which have brought many hours of pleasure.

EQUIPMENT LISTS

The equipment lists are broken into four groups, SCR-274N & ATA/ARA, AFC-5, Type 12,
and Miscellaneous. Some very minor specs are presented on the receivers and transmitters
and, where possible, A.R.C.'s part number is given. To assist in locating a particular piece, the
lists are broken into sections-Receivers, Transmitters, etc.

SCR-274N, ATA/ARA

Receivers

Identification
Freq. RNA SCR-274N Navy (ARA) IF Sense Select(kHz)

(MHz) Mil ARC# Mil ARC# (kHz) (uv) 3db lOdb
.19 - .55 BC-453 7594 46129 7839 85 7 1.7 3.1
.52 - 1.5 BC-946 46145 5950 239 8 2.9 4.9

1.5 - 3.0 .... 46104 5005 705 6 3.9 6.4

3.0 - 6.0 BC-454 7595 46105 5006 1415 7 7.5 12.5

6.0 - 9.1 BC-455 7596 46106 5007 2830 8 9.8 24.2

Transmitters

Identification
Freq Rng SCR-274N Navy (ATA) Power
(MHz) Mil ARC# Mil ARC# In(W)

2.1 - 3.0 .... 52232 7916 89

3.0 - 4.0 BC-696 52208 5009 88

4.0 - 5.3 BC-457 7632 52209 5010 88

5.3 - 7.0 BC-458 7633 52210 5011 90

7.0 - 9.1 BC-459 7634 52211 5012 90

Accessories

Identification
Item Name SCR-274N Navy ARC# Notes
Modulator BC-456 50083 7591 ARC # for Navy is 5013
Antenna Relay BC-442 29125 5017
Dynamotor, Rec DM-32 21531 7351 250v, 60ma
Dynamotor, Tran DM-33 21626 5168 575v, 160ma continuous
540v, 250ma intermit
Adapt., Rem Ctl FT-230 49107 6433
Adapter, Power FT-310 62036 9074 For Inst. Land. Sys.
Adapt., Lcl Ctl FT-260 - 6434

Control Boxes

Identification
Function SCR-274N Navy ARC#
Transmitter BC-451 23243 7095
1 Receiver BC-473 23261 7043
2 Receivers BC-496 23155 6546
3 Receivers BC-450 23251 5014

Racks and Mounts

Trans & Rec

Identification-Rec Identification-Trans
# Units SCR-274N Navy ARC# SCR-274N Navy ARC#
1 Mount FT-231 - 7059 FT-232 - 7061
Rack FT-233 - 7509 FT-234 - 7507
2 Mount FT-279 46085 5694 FT-227 52213 7062
Rack FT-277 46110 5018 FT-226 52212 5020
3 Mount FT-221 46150 7060 FT-262 - 7063
Rack FT-220 46149 7537 FT-276 - 7638
4 Mount FT-278 - 5696 FT-332 - 7064
Rack FT-264 - 5019 FT-331 - 6090

Other Mounts

Identification
Unit Mounted SCR-274N Navy ARC#
Modulator FT-225 50084 7058
Antenna Relay FT-229 29126 7056
Ctl Box, Trans FT-228 * 7083
Ctl Box, 1 Rec FT-235 * 7053
Ctl Box, 2 Rec FT-240 * 6831
Ctl Box, 3 Rec FT-222 * 7054

Miscellaneous

Identification
Item Name SCR-274N Navy ARC-5 Notes
Dial, .19-.55 MHz MC-214 * 6051 For ctl boxes
Dial, .52-1.5 MHz MC-415 * 6052 " " "
Dial, 1.5-3.0 MHz -- * 7575 " " "
Dial, 3.0-6.0 MHz MC-213 * 6053 " " "
Dial, 6.0-9.1 MHz MC-2i2 * 6054 " " "
Wired Plug PL-192 - 6787 Used with Lcl Ctl
Adapt.
Kit, Tuning Shaft MC-215 * 6151
Knob, Lcl Tuning MC-237 - 6743 Also MC-236
Adapter, Rt angle MC-211 - 6357 For tuning shaft

* designates no unique identification assigned to this piece.

ARC-5

Receivers

Freq Rng Ident IF Sens Select(kHz)
(MHz) ARC-5 ARC# (kHz) (uv) 3db lOdb
.19 - .55 R-23 9602 85
.19 - .55 R-23A 10007 85 5 1.1 2.2
.19 - .55 R-148 10008 85 5 1.1 2.2 *12v Fil.
.52 - 1.5 R-24 9603 239 7 2.1 4.0

1.5 - 3.0 R-25 9604 705 7 3.2 6.0

3.0 - 6.0 R-26 9605 1415 6 7.3 13.0

6.0 - 9.1 R-27 9606 2830 6 13.0 26.0
100 - 156 R-28 12mHz

Transmitters

Freq Rng Identification Power
(MHz) ARC-5 Navy ARC# In(W)
.50 - .80 T-15 52302 9315
.80 - 1.3 T-16 52303 9316

1.3 - 2.1 T-17 52304 9317

2.1 - 3.0 T-18 52305 9308 106

3.0 - 4.0 T-19 52306 9309 102

4.0 - 5.3 r-20 52307 9310 107

5.3 - 7.0 T-21 52300 9311 96

7.0 - 9.1 T-22 52309 9312 99
100 - 156 T-23

Ident

Accessories

Item Name ARC-5 ARC# Notes
Modulator MD-7 9313 Navy Acct'g # is 50141
Antenna Relay RE-2 5017
Antenna Tuner TN-6 9607
Dynamotor, Rec DY-1 250v, 60ma, 12v in
" " DY-2A 7351 " " , 24v in
" " DY-2B 10009 " " "
Dynamotor, Tran DY-8 5168 575v, 160ma continuous
540v, 250ma intermit
Adapt., Rem Ctl MX-21 6433
Adapter, Power MX-20 9074 For Inst. Land. Sys.
Adapt., Lcl Ctl C-24 6434
Adapter, Audio MX-19 9595

Control Boxes

Ident
Controlled Function ARC-5 ARC# Notes
Remote Ant/Loop Sw C-25 Via mech. link to rec.
1 Rec, Tunable C-26 9601
1 Rec, Lock-tuned C-27 9850
HF Transmitters C-29 7314
HF Trans, VHF Chan C-30 Push-button Tr, Ch sel
HF Trans, VHF Chan C-30A 9910 Rotary Tran, Chan sel
Main Ctl Box C-38 9610 Recs: 2 HF lock-tuned,
1 VHF, 1ARR-2,
Trans & Rec Audio
Auxiliary Ctl Box C-39 9901 ICS/Radio Sel, T & R Audio
1 Rec, VHF C-42
3 Rec, 2 HF & 1 VHF C-43 HF Rec are Tunable
Auxiliary Ctl Box C-48 9902 As C-39, Has Mic Relay
1 Rec, Tuneable C-125 9911 Panel Mount, Like C-26
1 Rec, Tunable LF C-744 New Panel Mt, No BFO Ctl

Jack & Junction Boxes

Ident
Function ARC-5 ARC# Notes
Jack Box, Mic/Tel J-16 9905 No Vol Ctl or Mic Relay
Junct Box, System J-17 9903 For Multi-system Install.
Jack Box, Mic/Tel J-22 9867 No Mic Relay
Jack Box, Mic/Tel J-22* 9907 Has Vol Ctl & Mic Relay
Ctl Split, VHF Chan J-28 9609 For C-30* to R-28 & T-23
Ctl Split, Trans J-34 9562 For Multiple Trans Racks
On 1 Modulator

Racks & Mounts

Trans & Rec

Ident-Rec Ident-Trans
# Units ARC-5 ARC# ARC-5 ARC#
1 Mount MT-5 7059 MT-68 7061
Rack MT-7A 7509 MT-69 9306
Rack MT-411 9202 - -- Wired for 12v
2 Mount MT-62 5694 MT-70 7062
Rack MT-63 5018 MT-71 9307
3 Mount MT-64 7060 MT-72 7063
Pack MT-65 7537 MT-73 9593

4 Mount MT-66 5696 MT-74 7064
Pack MT-67 5019 MT-75 9394

Other Mounts

Ident
Unit Mounted ARC-5 ARC# Notes
Modulator MT-76 7067
Antenna Relay Mt-77 7065
Antenna Tuner MT-159 7057
Ctl & Jack Box MT-78 9451 For C-27, j-16,-22,-22'
Control Box MT-4 7053 For C-26
Ctl & Junct Box MT-80 7083 For C-29,-30,-39,-48'
J-28,-34
Control Box MT-98 7054 For C-38,-43
Junction Box MT-84 9904 For J-17

Miscellaneous

Ident
Item Name ARC-5 ARC# Notes
Dial, .19 - .55 MHz ID-25 6051 For tunable Rec Ctl Box
Dial, .52 - 1,5 MHz ID-26 6052 " " " " "
Dial, 1.5 - 3.0 MHz ID-27 7575 " " " " "
Dial, 3.0 = 6.0 MHz ID-28 6053 " " " " "
Dial, 6.0 - 9.1 MHz ID-29 6054 " " " " "
Wired Plug J-33 6787 Used With Lcl Ctl Adapter
Kit, Tuning Shaft * 6151
Knob, Lcl Tuning * 7643
Knob, Lcl Ant/Loop * 7491
Knob/Cap, Lock-tun'g * 9554
Adapter, Rt Angle MX-22 6357 Used with Tuning Shaft

* No unique identifier in ARC-5 system

Note: The following are components of the ARR -2 system that
are used with the ARC-5 system: DY-l, DY-2A, DY-2B, MT-4,
MT-5, MT-7A, MX-22.

Type 12

Receivers

Freq Rng Identification IF Sens Select(kHz)
(MHz) Civilian Mil (_Hz) (uv) 6db 60db Notes
.19 - .55 R-11(12v) P-510 85k 2 5.6 12v
R-11(24v) R-511 85k 2 5.0 24v
.52 - 1.5 R-10 239k 2 7.6 12 or
24v
108 - 136 R-15(12v) 15m 2 100. 350.0 12v
R-15(24v) R-509 15m 2 100. 350.0 24v
118 - 148 R-19(12v) R-507 15m 2 100. 350.0 12v
R-19(24v) R-508 1Sm 2 100. 350.0 24v

Transmitters

Freq Rng Identification Tubes Power
(MHz) Civilian Mil Used Out(w) Notes

116 - 132 T-11A 6AQ5 2 12 or 24v
T-11B(12v) T-336 5763 2+ 12v
T-11B(24v) T-366 5763 2+ 24v
132 - 148 T-13 6AQ5 2 12 or 24v
(see note) T-13A(12v) T-363 5763 2+ 12v
T-13A(24v) T-364 5763 2+ 24v

Note: Freq may be lowered to 125 mhz by using capacity pla tes
ARC# 15392 for the T-13 and ARC# 15900 for the T-13A.

Dynamotors

D-10A(12v), ARC# 14480: 12v,3.4a in, 250v,85ma out
D-10A(24v), APC# 14482: 24v,l.7a in, 250v,85ma out

Note: Dynaverter DV-10,-1OA is later replacement

Junction & Jack Boxes

Item Name Ident Notes
Jack Box J-10 Aircrew Mic/Tel
Junction Box J-12 32 Tie points. 12v
Junction Box J-13 32 Tie points, 24v
Junction Box J-15 56 Tie points, 24v

Control Boxes

Ctl'd Function Ident Notes
1 Rec C-16 Dial for R-11A
1 Rec C-17 Dial for R-15
Loop Heading C-18
3 Rec. 2 Tran. C-24 1 ea, R-lO,-ll,-15, 2 Type 12 Trans
Loop Heading, Panel Mount
3 Trans C-25 2 Type 12, 1 Extern Trans
2 Rec. 3 Trans. C-36 1 ea: R-11,-19, 2 Type 12 trans.
I Extern Trans, Loop Heading.
Panel Mount
2 Rec. 3 Trans C-37 Like C-36, No Loop or Panel Mount
2 Rec. 3 Trans C-38 1 ea: R-11,-15. 2 Type 12 Trans,
1 Extern Trans
2 Rec. 2 Trans C-39 As C-36, panel Mount, No Extern Trans
Loop Heading
3 Rec. 3 Trans C-40 1 ea: R-11,-19, Tunable HF ARC-5 Rec.
1 ea: HF & VHF ARC-5 trans, Extern Trans
Panel Mount
1 Rec. Loop Hdg C-48 Dial for R-11, Loop Heading, New Panel Mt
1 Rec. 4 Trans C-56 Dial for R-19, 3 Type 12 Trans, 1 Extern
Trans, Whistle-stop, New Panel Mount

Mounts

Unit Mounted Ident Notes
1 Transmitter M-11
1 Receiver M-12
Control Box M-13 For C-37,-38, Like ARC# 6831
Control Box M-18 For C-16,-17,-18, Like ARCF 7053
Control Box M-19 For C-25, Like ARC# 7083

Miscellaneous

Item Name Ident Notes
Antenna, VHF A-12 3-Section Rod
Antenna, Loop L-10 9" Dia, Mil, AT-382
Kit. Wire Antenna - ARC# 12296
Kit. Tuning Shaft - ARC# 6151
Wired Plug - ARC# 11934. Used when oper'g Rec
without Trans.

Related Equipment

SCR-274N, ATA/ABA

Receiver Test Set-up, ARC# 7918 (Mil: RC-54A)
Consists Of: 7369 Meter Panel, Single Rec Rack & Mount,
Dynamotor, Tuning Knob, and Cables
Transmitter Test Set-up, ARC# 7919 (Mil: RC-55A)
Consists of: 7507 Meter Panel, Single Trans Rack & Mount,
Modulator & Mount, Dynamotor. Ctl Box, Cables,
and ARC# 7777 Dummy Ant. (Mil: A-61A)

ARC-5

Receiver Test Set-up (as SCR-274N, ATA/ARA)
Transmitter Test Set-up, ARC# 9558
Consists of: 9556 Meter Panel, Crystals for 3, 4, 5.3,

7. & 9.1 MHz and contents of ARC# 7919 Set -up.
R-4/APR-2 Homing Receiver, 234-258 MHz
Includes: C-2/APR-2 Ctl Box (if rec is used alone.)
MX-2/ARR-2 Wired Plug for Rec Rack

A.R.C. Type 12

R-20 Fixed-tuned (75 MHz) Marker Beacon Rec
R-22 .55-1.5 MHz Rec (Like R-10 but later model)
R-836 .19-1.75 MHz ADF Rec, Part of ARN-59 System
Includes C-2275/ARN control Box
TV-10 (CV-431/AR) Transvertor
Trans: 228-258 MHz, Converts 228-258 MHz to 118-148 MHz Rec.
Type 15 Equipment (VOR/ILS Receiving Eq't)
R-13 (R-445/ARN-30) 108-136 MHz Rec.
R-34 (R-1021/ARN-30D) 108-126.9 MHz Crystal-ctl'd Rec
B-13 (CV-265/ARN-30) VOR/ILS Converter
E-14 (MT-1175/ARN-30) Equipment Rack
C-81,-88 Control Boxes For R-34
C-3436A/ARN-30 Ctl box for R-1021/ARN-30D

PINOUTS

On the following few pages are pinouts for the connectors on most of the equipment
previously listed. The same order of categories is preserved as used in the previous section
however they are collected so that all the receivers are together, etc for the main equipment.
The related equipment is still separate and at the end of the section.

Except for two cases, all the connectors are numbered anticlockwise when viewed from the
outside. The exceptions are the connectors on the rear of the rack-mounted receivers and
transmitters, and those on the rear of the receiver adapters.

The number in parenthesis is A.R.C.'s part number for the receptacle in question. The
'Connectors' section following this one is ordered numerically on this number, and can be
used to locate the proper plugs to match.

Notes are indicated by an asterisk and a one or two digit number (for example, *4 or *28.)
The notes are at the end of the section. The number refers to a particular note.

An Asterisk used as a suffix to a unit's identifier means that all versions of the unit are being
referenced. For example J-22- refers to the J-22, J-22A, and J-22B.

Receivers

Command Receivers (All Series)
J-1 (4724) To Adapters *8
1 Gain Ctl 4 Nav Audio *1 7 +LV Source Out
2 Gnd 5 CW Shut-off 8 +HV Out
3 n/c 6 +LV to Rec

J-3,-102 (5488) To Rack
1Gnd 4 CW Shut-off *7 7 +HV out
2 Audio Out 5 +Vscr out *8
3 Gain Ctl 6 +LV Source In

J-103 (5577) To Channel Select Ctl Box *9
1 Sel Chan A 3 Gnd 5 Sol Chan D
2 Sol Chan B 4 Sol Chan C 6 n/c

A.R.C. R-10,-ll
J-502,-602 (12427) To Primary Power Source
A +LV Source In B Gnd

J-503,-603 (11905) To Rec Ctl Box
A Audio Out C Gnd E Sons
B Loop Relay D +LV to Rec F +LV Source Out

J-506,-606 (11905) To Transmitter *2
A +HV to Trans C Gnd E +HV to Rec
B Audio Out D +LV to Trans F n/c

A.R.C R-15,-19
J-lO1,-301 (12427) To Primary Power Source
A +LV Source In B Gnd

J-102,-302 (11905) To Rec Ctl Box
A Audio Out C Gnd E Sons
B Audio Hi-Lo D +LV to Rec F +LV Source Out

J-103,-303 (11905) To Transmitter *2
A +HV to Trans C Gnd E +HV to Rec
B Audio Out D +LV to Trans F n/c

Transmitters

SCR-274N, ATA
J-64 (5488) To Rack
1 Gnd 4 P.A. Vscr 7 P.A. B+
2 P.A. Grid 5 Select (key)
3 Osc B+ 6 +LV In

ARC-5
J-69,-308 (9302) To Rack
1 n/c 4 Gnd7 P.A. 5*
2 Osc B+ 5 +LV In
3 Select (key) 6 P.A. Vscr

J-79 (9849) To Antenna Tuner *3
1 Select (key) 2 Gnd 3 +LV Out

J-309 (7026) To Channel Select Control *10
1 Sel Chan A 4 Gnd 7 Voltage Reg.
2 Sel Chan B 5 Sel Chart D 8 n/c
3 Sel Chan C 6 Key

J-307 (6418) To Test Set *10
1 Osc Ig 4 Gnd 7 +LV
2 1st H.G. Ig 5 P.A. Ig 8 +HV
3 2nd H.G. Ig 6 P.A. Ik

A.R.C. T-11(),-13()
J-204,-404,-2302,-2402 (11905) To Rec
A +HV to Trans C Gnd E .HV to Rec
B Rec Audio In D +LV In F +LV Source

J-205,-405,2306,-2406 (12093) To Audio
A Mic In C Gnd
B Key D Tel Out *4

J-207,-407,-2303,-2403 (12097) To Ctl Box
A Sel Chan 1 D Gnd G +LV to Ctl Box
B " " 2 E Sel Chan 4 H +LV In
C " " 3 F " " 5 *5

Accessories

Modulator (SCR-274N, ATA/ARA)
J-52 (5577) To Rec Rack
1 Sidetone Inject 3 Gnd 5 Key
2 n/c 4 n/c 6 +LV

J-53 (7024) To Primary Power Source
1 +LV Source In 2 Gnd 3 +LV Source In

J-54 (7027) To Control Box
1 Sel Trans 1 7 Gnd 13 Modulator Cath.
2 " " 2 8 Mic 14 1000-cycle Off
3 " " 3 9 Key 15 +LV to Eq't
4 " " 4 10 Voice Sidetone 16 Voltage Reg.
5 Meter + 11 Tone Sidetone 17 Sidetone Inject
6 Meter - 12 Dyn. Relay 18 +LV Source Out

Modulator (SCR-274N, ATA/ARA), Con't
J-58 (7025) To Trans Rack
I Meter + 5 Gnd 9 Sel Trans 1

2 Meter - 6 Sel Trans 4 10 P.A. B+
3 Key 7 " " 3 11 0sc. B+
4 +LV 8 " " 2 12 P.A. Vscr.

Modulator (ARC-5)
J-52 (5577) To Rec Rack
1 Sidetone 1 3 Gnd 5 Key
2 A-Tel 4 B-Tel 6 +LV

J-53 (7024) To Primary Power Source
1 +LV Source In 2 Gnd 3 +LV Source In

J-70 (9417) To Trans Rack
1 +LV 5 Sel Trans 3 9 +HV
2 Sel Trans 1 6 " " 4 10 Osc. B+
3 " " 2 7 Key 11 Test Relay
4 Gnd 8 P.A. B+ 12 P.A. Vscr.

J-74 (7026) To External Equipment
1 Mic 4 Gnd 7 Key
2 A-Tel 5 Sidetone 1 8 +LV
3 B-Tel 6 Sidetone 2

J-78 (5571) To Ctl Box
1 Sel Trans 1 7 Gnd 13 Modulator Cath.
2 " " 2 8 Mic 14 l000-cycle Off
3 " " 3 9 Key 15 +LV To Eq't
4 " " 4 10 Voice Sidetone 16 Voltage Reg.
5 n/c 11 Tone Sidetone 17 Sidetone Inject
6 Sel Common 12 Dyn. Relay 18 +LV Source Out

Antenna Relay (All Series)
J-61 (7023) To Trans Rack
1 Key 3 Gnd 5 Meter ­2 Meter + 4 +LV In

Antenna Tuner (ARC-5)
J-1601,-1602 (9849) *11
1 Key 2 Gnd 3 +LV In

Remote Ctl Adapter (SCR-274N, ARA, ARC-5)
J-31 (6063) To Rec Adapt. Cavity
1 n/c 4 n/c 7 jmpr to 6
2 n/c 5 n/c 8 n/c
3 n/c 6 Jmpr to 7

Power Adapter (SCR-274N, ARA, ARC-5)
J-29 (6076) To Rec Adapt. Cavity
1 n/c 4 n/c 7 +LV (Jmpr to 6)
2 Gnd 5 n/c 8 +HV
3 n/9 6 +LV (Jmpr to 7)

J-30 (2226) To External Eq't
25 +LV 27 Grid 36 n/c
26 n/c 35 +HV

Lcl Ctl Adapter (SCR-274N, ARC-5)
J-32 (6962) To Rec Adapt. Cavity
1 Gain Ctl 4 n/c 7 +LV to Rec
2 Gnd 5 CW Shut-off 8 n/c
3 n/c 6 +LV Source

Audio Adapter (ARC-5)
J-27 (6036) To Rec Adapt Cavity
1 Gain Ctl 4 Navig. Audio 7 +LV (Jmpr to 6)
2 Gnd 5 CW Shut-off 8 n/c
3 n/c 6 +LV (Jmpr to 7)

J-28 (9336) to External Eq't
1 Audio 2 Gnd 3 Relay Ctl

Control Boxes (SCR-274N, ATA/ARA)

Transmitter Ctl Box
J-55 (7027) To Modulator
1 Sel Trans 1 7 Gnd 13 Modulator Cath.
2 " " 2 8 Mic 14 1000-cycle Off
3 " " 3 9 Key 15 +LV to Eq't
4 " " 4 10 Voice Sidetone 16 Voltage Regulator
5 Meter + 11 Tone Sidetone 17 Sidetone Inject
6 Meter - 12 Dyn. Relay 18 +LV Source

J-56 (2674) To External Meter
+ Meter + (blank) Meter -

Receiver Ctl Boxes (Single or Multi.)
J-25,-26,-27 (6418) To Rec Rack
1 +LV Source 4 Gnd 7 CW Shut-off
2 Rec Audio 5 B-Tel 8 A-Tel
3 Gain Ctl 6 +LV to Rec

Control Boxes (ARC-5)

Single Rec, Tunable (C-26)J-4 (6418) To Rec Rack
1 +LV Source 4 Gnd 7 CW Shut-off
2 Rec Audio 5 B-Tel 8 A-Tel
3 Gain Ctl 6 +LV To Rec

Single Rec, Lock-tuned (-27)
J-5 (9835) To Rec Rack
1 Gain Ctl 2 Gnd

HF Trans Ctl (C-29)
J-77 (5571) To Modulator
1 Sel Trans 1 7 Gnd 13 Modulator Cath.
2 " " 2 8 n/c 14 lO00-cycle Off
3 " " 3 9 Key 15 +LV to Eq't
4 " " 4 10 Voice Sidetone 16 Voltage Reg.
5 n/c 11 Tone Sidetone 17 Sidetone Inject
6 Sel Common 12 Dyn. Relay 18 +LV Source

HF Trans & VHF Chan Sel (C-30,-30A)
J-402,-1700 (5571) To Modulator

- Pinout same as J-77 on C-29 above)

J-401,-1701 (7025) To VHF Eq't
1 Trans Chan A 5 Gnd 9 Rec Chan C
2 " " B 6 Key 10 " " D
3 " " C 7 Rec Chan A 11 Voltage Reg
4 " " D 8 " " B 12 n/c