Operating instructions
for
bare
wires
touching
the
chassis
or
other
rr'ires.
c.
Be
sure
that
the
labels
on
the
tubes
in
the
various
sockets
correspond
to the
correct
tube
numbers
for
these
positions
as
given
in
the
manual.
Replace
or interchange
any
tubes
rvhich
have
the
wrong
numbers.
Replace
bro_
ken
tubes.
Inspect
for
loose
tube-socket
con_
tacts.
d. Inspect
the fuses.
Check
carefully
for
short
circuits
wherever
a
power
supply
with
a
blown fuse
is
found.
e.
Inspect
the
dial mechanism.
Be
sure
that
the
dial
turns
smoothly.
/.
Check
all switches
and
controls
for
ease
of
operation.
g.
Inspect
all
power
plugs
and
cables.
Re_
place
or
repair
any
plugs
or
cables
that
are
broken.
h.
Inspect
for
loose
or missing
screws,
espe_
cialiy
those which
fasten
tube
sockets
in
place.
73. Input
Resistonce
Meosurements
for
Power
Supply
PP-308/URR
ffig.
aa)
a.
Trouble
rvithin
the
porver
supply
often
ntay
be
detectecl
b1'
checking
the
resistance
of
the
filament
and h-v
circuits
before
applying
po\\-eÌ'
to
the
unit.
Make
the following
checks
ìrefore
attempting
to
put
the
pou'er
supply
into
olreration.
Disconnect
the
por,r'er
source
and
the receiver-power
supply
interconnectine
cable.
ó.
The
resistance
betu'een
terminals
6 and
10
of
J101 should
read
infinity.
If
there
is
a re_
sistance
reading,
check
tube
V101,
resistor
R111,
and
the wiring
to these
components.
c.
The
resistance
betrveen
terminais
g
ancl
10
(ground)
of
J101
shoulcl
reail
62
ohms
for
r,ll settin.qs
of
POWER
SELECTOR,
su,itch,
;rcept
DRY
BAT.
In
this
ìatter:
morle
of oper_
.tion,
the
resistance
shorilcl
reacl 162
ohms.
if
lte
l"esistance
varies
appreciabll'
more
than 10
',r'cent.
check
resistors
R1il8,
R109,
ancl
the
rring
to section
6
of 51()1.
1.
The
resistance
betu'een
terminals
2
and
,1
.1101
shoLrlrì
rcatl
1.1
ohms.
if
the
reacling
,'s
uot
corresponcl
to this
value,
check
T103.
',
rll:ìA
e.
The
resistance
betrveen
J10gA
and
J10BD
(POWER
INPUT
receptacle)
should
be Lz
ohms
with
POWER
ON-OFF
switch
turned
to
ON.
If
the
reading
is
higher,
check
T101
pri_
mary
and T102
terminals
11
to 12.
If
the
read_
ing
is
lower,
check
T101,
T102,
C102A,
and
C102B.
Turn
POWER
ON-OFF
sn.itch
to
OFF:
the
reading
should
be infinity.
/.
The
resistance
between
J10BB
ancl
J10BC
should
read
infinity.
Turn
pOWER
ON_OFF
switch
to
ON;
the
resistance
should
read
.2
ohm
for
the
6
V setting,
.04
ohm for
the 12
V
setting,
and
2.2
ohms
for
the 24
V
settins
of
s101.
g.
Measurements
of resistance
from
J104D
to
J104C,
(DRY
BATTERY
receptacle)
should
be 162
ohms
when
POWER
SELECTOR
srvitch
5101
is
turned
to DRY
BAT.
and
62 ohms
u,hen
switched
to any
other
mode
of
operation.
If
resistance
reading
is
incorrect,
check
R10g
and
R109.
b.
Resistance
from
J104A
to
J104D
should
read
infinity.
Check
S101,
3109,
and
the
con_
tacts
of
reìay
K101.
74.
Input
Resistonce
Meosurements
for
Rodio
Receiver
R-174/URR
6s.
45)
Trouble
within
the
receiver
often
may
be
cie_
tected
by
checking
the resistance
of
the
filament
and
h-v
circuits
before
applying po\ver
to
the
equipment.
Make
the
follorn'ing
checks
before
attempting
to
put
the receiver
into
operation.
I)i-sconnect
ail
cabìes
to
the
receiver.;
turn
R.F.
GAII{
and
A.F.
GAIN
controls
to
maximnm
cìockrvise
direction;
turn
OIITpUT
HIGH_
LOW
srvitch
to HIGH;
turn BAND
SW. srvitch
to
band
1;
and tru'n
PHN.-C.W.,NET-CAL.
functiun
ss'itch
to
PHI{.
o.
The
resistance
lietu.een
terminal
6
and
terminal
10
of
J4 shoulcl
read
110K
ohms ,t.I0
percent.
If
the
l.esi.qtance
is
appreciabh,
lou,er,
check
capacitor
C37, the u-iring
to
pins
2
ancl lj
of
all tLrbes,
ancÌ
pin
K
of
J1.
If
the
resistance
is
appreciabiS-
higher
than
l10K
ohms,
R1l3
oi'
the 10,000-olim
resistor
in
Tl2
is
pr:obablv
open;check
the
R.i-
c;r'cuit.
To
prerrent
ltossi_
ble
damage
to
thc
pi;\\-el'
suppll',
correct
rlÌ
abnormal
cttnditii:ls
lrefole
connectirrq.
lhe
po\Yer
.cllppl)'.
57