B
ef
o
r
e
in
s
talling
a
12
A
U
7
, the tu
b
e may b
e
a
ge
d a
s
f
o
llo
ws
:
co
n
n
e
ct
t
h
e
plat
es
together
and
a
p
p
l
y
11
5
v
olts dc. Op
e
rate
the
g
rids
and
c
a
t
hod
es
with no
vo
lta
ge
appli
ed
,
and
op
e
r
at
e
the he
a
t
e
r
s
at 6
.
3 volts
. T
he tube
s
ho
u
ld
be
op
e
rat
e
d
in thi
s
manner
fo
r
a m
i
nimu
m
o
f
1
2 hour
s
b
ef
ore
it i
s
in
s
tall
e
d
i
n
the in
st
rum
e
nt.
Th
e
W
V
·77C th
en
can
b
e r
e
c
a
librated
.
A
n alternat
e,
a
nd
u
s
uall
y
s
ati
sfac
to
ry
,
ag
i
ng
proc
e
du
r
e
c
on-
s
i
sts
of
o
p
e
r
at
i
n
g
th
e
n
ew tu
b
e
in
t
h
e
WV-
77
C
f
or a
p
proxi
-
mat
e
l
y
36 hou
rs
,
a
f
t
e
r
w
h
i
ch
time
th
e
i
n
s
t
r
ument
may
be
r
ec
ali
b
rated.
If
thi
s
proced
u
re
i
s
un
sa
t
i
sf
ac
t
o
r
y
,
t
h
e fir
s
t a
g
in
g
pro
ce
d
ure
s
h
ou
ld
b
e
f
ollo
we
d
.
If
i
t
b
e
co
me
s
n
e
ce
ss
ary
to
r
epla
c
e
t
h
e 12A
L
5, the
tu
be ca
n
be
ag
e
d
f
o
r
a
minimu
m
p
e
r
iod
of 36
hou
r
s
b
y op
e
r
ati
n
g
it in
the \VV-
77
C.
Af
t
e
r
t
h
is
pe
r
iod
of time
,
th
e i
n
s
trum
e
nt
may
b
e
r
ec
ali
u
rat
ed
acco
rdin
g
t
o
t
h
e
pro
c
edur
e
outl
i
n
e
d
u
nd
e
r
"A
C
C
a
libration
C
h
eck"
.
Battery Testing and Repl
a
cement
C
a
ut
i
on
:
D
o
not a
llo
w
e
xhausted
c
e
ll
s
to
r
emain
i
n
s
ide
t
he
ca
se
o
f th
e
WV-7
7
C.
C
h
e
mi
c
a
l
s
from
deter
i
ora
t
ed
cell
s
may
dama
ge
the instr
u
m
e
nt
.
Th
e
batt
e
r
y
s
ho
u
l
d
b
e test
e
d
to
i
n
sure ac
c
u
ra
c
y o
f
re
s
i
s
t
a
n
c
e
m
e
a
s
ur
e
men
t
s
.
To t
e
st
b
att
e
r
y,
p
r
oceed
as fo
ll
ows
:
L S
e
t .Functio
n
se
l
ect
or
t
o "
OH
l\.
lS"
.
2
.
Se
t Rang
e
s
e
l
ec
t
or
t
o
"R x 1
"
s
c
a
le
.
3
.
Rotate
OH
2V
IS A
DJ
c
ontrol
t
o bring
p
oint
e
r
to f
u
ll s
c
al
e
.
4
.
Sh
ort·circuit
th
e
prob
e
tip
and
gr
ound
clip
f
or
about
t
en s
e
c
ond
s
.
5
. Op
e
n the
s
h
o
rt-
circu
i
t
and
im
m
edi
a
t
e
ly
observ
e
th
e s
c
al
e
i
n
d
i
c
a
t
ion.
A
n appr
e
ciable
d
ev
iation
f
rom
f
u
ll
-
s
c
a
l
e
i
n
di
c
ation
r
eve
al
s
we
a
k c
e
ll
s
wh
ich
should
b
e
rep
l
ac
e
d.
Ohms Adjust
m
ent
In o
r
de
r
t
o ob
t
ain
e
xa
c
t
l
y
f
u
ll-
sc
al
e
d
e
flec
ti
on
of th
e
met
e
r
w
h
e
n
s
witchin
g
th
e
ran
ge
s
e
l
ec
tor
fr
o
m a
l
ow range
p
o
s
it
i
on
t
o
the R x 1
M
EC
p
os
itio
n,
i
t m
a
y be n
e
c
e
ss
ary
to read
j
u
s
t
the O
H
MS
ADJ
control.
The
necess
i
t
y
for thi
s
r
e
ad
j
u
s
tm
e
nt
c
an
b
e
m
in
i
miz
ed
b
y
che
c
king
th
e
b
a
u
e
ry
and
in
s
tall
i
ng
a
12AU
7
tub
e
w
i
th a
l
o
w v
al
ue
of g
r
id curr
e
nt.
R
e
f
er
t
o
Tube
R
e
pl
ace
m
e
nt
se
c
t
i
o
n.
RCA Repair Service
S
.
If
s
t
e
p
s 2
and 4 abo
ve ca
nn
o
t
b
e ac
c
ompli
s
hed,
t
h
e
t
w
o
t
riode
u
nit
s
o
f th
e
1
2A U
7
t
uh
e
s
are n
o
t in clo
se
en
o
ugh
b
a
l
.
ance for thi
s
appl
i
c
at
i
on
and th
e
tube
s
hou
l
d be replac
e
d.
DC Zero Check
L S
e
t funct
i
oll
s
elec
tor
to
"
-
VOLTS
"
.
2
.
S
e
t ran
ge
se
le
c
tor
o
n "3V
"
.
3
.
Rotat
e
t
h
e Z
ERO
ADJ c
o
ntrol
un
t
i
l
th
e
m
ete
r p
o
i
nt
e
r
i
s
at ze
ro.
4
. Turn
r
an
ge
s
wit
c
h
to "1200V
"
.
5
.
If
th
e
m
ete
r
p
o
int
e
r
d
e
via
tes
from z
e
ro
by
more
t
han on
e
divi
s
ion
011
the 0 to 12 met
c
r
sca
l
e,
replace
th
c
12AU
7
(
s
e
e
s
ecti
on
o
n
Tu b
e
R
e
pla
ce
ment
)
.
AC Zero
Che
c
k
J
.
Set the rang
e
selec
to
r
o
n
"3
V
"
and
t
h
e
f
u
ncti
o
n
s
ele
c
t
or
on
"
+
VOL
T
S
"
.
2
.
Rotat
e
ZERO
A
D
J
contr
o
l
until
me
t
er
r
ead
s
1
0 volt
s
on
th
e
60V m
e
t
e
r
sc
al
e
.
3
.
T
u
rn
th
e f
un
c
t
i
on
se
l
ec
tor
t
o "
AC VO
LT
S"
.
4
.
If
t
h
e
m
e
t
e
r do
es
n
o
t r
e
ad b
et
w
ee
n
7
a
n
d 1
3
volt
s
,
r
e
p
la
ce
th
e
12AL5
. T
h
c
u
se
of a
1
2ALS whi
c
h r
e
s
ult
s
i
ll a
m
ete
r
re
a
d-
in
g
ou
t
s
id
e
o
f ,hi
s 7
-13
v
olt ra
n
ge
will
n
ot
i
mpai
r
the a
c
cu
r
a
~
y
of
th
e
in
s
trum
e
nt
but
will,
how
e
v
e
r
,
require
mo
r
e
frequent
adju
s
tm
e
nt
o
f t
h
e
Z
E
RO AD
J
control.
Calibration
1. S
e
t
t
h
e
ra
n
ge
s
ele
cto
r
to ;
'
60V" a
n
d
t
he fu
nc
t
i
o
n
se
l
ec
tor
to
"+
VO
LT
S"
_
2. Se
t
thc m
ete
r
point
e
r
to z
er
o b
y
usin
g
the ZE
R
O
A
D
J
co
n
t
ro
L
3. S
e
t the s
l
id
i
n
g
switch
on t
h
e pr
o
b
e
to
"
DC
"
.
4
.
Con
n
e
ct
t
h
e Gr
o
un
d
Cable
to
t
he n
eg
ativ
e
t
e
rminal
a
ll
d
th
e
pr
o
be
tip
to
th
e
po
s
iti
ve
ter
minal
o
f
a sou
r
c
e
o
f
DC
Volta
g
e
that
h
as
b
e
e
n
adjus
te
d
t
o
e
xa
c
tl
y
57 v
olt
s
.
N
ot
e
:
T
he
ac
c
u
rac
y
of
c
ali
b
r
a
tio
ll
c
annot
c
x
c
ee
d
t
h
e
a
c
cura
c
y
of t
h
e v
o
ltag
e s
t
a
ndard
s
which ar
e
us
e
d.
5
.
Adjust
t
h
e '
;
DC CA
L
" co
ntrol
(
R
-
23
)
in
s
id
e
t
h
e ca
se
f
or
a m
e
ter
r
e
adi
n
g
o
f
e
x
a
c
t
ly
57 volt
s
.
6
.
R
e
move
th
e
leads at t
h
e s
ource
of
v
oltage
.
7
.
Set the funct
i
on
s
el
e
c
tor
to
"
-
VOLTS"
.
8
.
Connect
th
e
Ground
C
able to the pOSi
L
i
\'
e
terminal
and the
prob
e
tip
to the
n
ega
ti
ve
t
e
n
J
linal
of the
dc
-
volt
ag
e
sou
rce
adju
st
e
d
to exactl
y
5
7
v
olt
s
.
The WV-77C should rea
d
57 volt
s
with
i
n
±3
%
.
9
.
If
t
he
WV-77C
ca
nn
ot
b
e ca
lib
ra
ted
ac
c
ording
t
o
the
foreg
o
in
g
ste
ps th
e
12
A U
7
am
p
lifier
tu
b
e ma
y
not b
e
pro
p
er
ly
ba
l
an
c
ed
f
or t
h
i
s a
p
p
lication
.
Tube Repl
a
ceillent
All t
u
be
s
su
ppl
i
ed
origina
ll
y
w
i
t
h
th
e
WV-77C
h
a
v
e been
t
h
o
r
o
ughly
a
g
ed
by operat
i
n
g
t
h
e
m
for
sev
e
r
al
hour
s
b
efor
e
i
llstallatiOri
i
n th
e
i
n
st
r
ument.
Th
is
prel
im
i
na
r
y
c
ondition
i
n
g
of a new tube
he
l
ps
to
i
ns
ur
e
stability
an
d
dep
e
ndab
l
e
p
e
r-
formanc
e
.
RCA ma
i
ntains
a comple
t
e
r
e
p
air
se
r
v
i
ce
f
or
the adj
ust
m
ent
,
c
alib
r
at
i
on,
and
m
ai
n
t
enanc
e
of
R
CA
t~st e
quipmen
t.
If
i
t
be
c
ome
s
n
ecessary
to service this e
q
ui
p
me
nt
,
t
h
e
r
ep
ort
f
o
r
ms
enclos
e
d
in t
h
is b
o
okle
t
s
houl
d be fille
d out
a
s d
esc
ri
be
d.
It
is
im
p
o
r
t
a
n
t
th
at
:
1.
Test
e
quipm
e
n
t
be pac
k
e
d
c
a
ref
ull
y
,
2. A full de
sc
r
i
ption
of the trou
b
le
be
i
nclude
d
in
t
he
re
po
r
t.
3
.
All
prob
e
s
and cable
s
b
e includ
e
d
wi
th th
e
in
strume
nt.
Att
e
n
t
io
n
to these de
t
a
ils
will
help p
r
event
damag
e
i
n
tr
ansit
and de
l
ay in repa
i
rs
.
. 12 •
Summary of Contents for VoltOhmyst WV-77C
Page 13: ...I ...
