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VOLTAGE
AND
RESISTANCE
CHART
TIME
HN*
DC VOLTS
DC
VOLTS
NO
SIGNAL
M
WATTS
AC
VOLTS
0
ke)
1.25
VOLTS
INPUT
ECC0$/12AX7
1
VI
2
3
U3
6
105
102
10
0
0
1.25
0.9
0.9
1.13
Moment
(4.
3
VAC
to
pin
9)
222
215
9.5
112
105
10
105
102
9.5
1
0
0
9.5
2
0
0
9.5
3
12.5
15
.1
445
fllamnt
(6.
3VAC
between!
4
-
-
?
335
320
6
8
0
0
9.5
9
340
325
1B2
SHI
V4
1
295
i
3
340
325
445
filament
(6.
3VAC
between)
6
7
295
8
All
wHbqm
and rvlitanca
tee
Mound
to
chmk.
Voltages o»e
otataU
T
ni
t
«M
o
MflK
Input
Impedatce
VTVM.
All
rol.no Mounnol)
ere
mode
wllfc
pin
3
erf
rtw
EZ81
grouixUd
except, of
ooune,
when
the
restitance to
gmuarf
of pin.
2
<md
8
of the
EZ81
is
bolng
choeW.
Operating
line
voltage
at
which
voltage
m
eas
u
reme
n
ts
arooiodo
H
I
I7volM
AC,
60cfx.
NOTti
ALL
VOLTAGE &
RESISTANCE
VALUES
MAY
VARY NORMALLY
BY *15*.
TROUBLE-SHOOTING CHART
SYMPTOM
CAUSE
House power
line
fuse
blows;
fuie,
FI,
remains
intgct.
Fuse, FI,
blows.
Any
or
all
tube
filaments
not
lit.
Short
in line
cord, J2,
J3
or associated
equipment plugged
info
J2
or
J3.
If
the amplifier causes
a replacement
fuse
to
blow
with
rectifier
tube
V4
removed, primary
or high voltage secondary windings
of
T2
are
incorrectly
wired
or shorted.
If
FI
does not
blow
after
replacement
(with
V4
removed),
check
for
short
In
B+
circuits,
defective
V4
and C8.
Open
lead
from
6.3
V
winding
of T2.
6.
3
V
winding
of
T2
open
DC
voltage
at
V4
cathode
(pin 3)
is
incorrect
as
specified
below.
-
a)
No
vo
l
ta
g
e
Defective V4.
C8
shorted internally or externally.
Connection
to
C8
broken.
b)
High
voltage
Connection
to
center
tap
of
h.
v. sec.
winding
of
T2
open.
Output
tubes
V2
and
V3
over-biased
or not
drawing
current.
c)
Low
voltage
Excessive current drain
in
amplifier.
Defective V4.
5
RESISTANCE
UNIT OFF
3KKQ
I.8KQ
1630
160-2000
330KO
0
950
160KQ
950
REMEDY
Repair
Check
and
repair or replace.
Check
and
repair or replace.
Repair
Replace
T2.
Repla ce
Replace or
repair.
Repair
Repair
See
trouble-shooting typical
stage.
See
trouble-shooting typical
stage.
Replace
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Table of Contents
Troubleshooting
