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4-4
230 VOLT
OPERATION
The
@
Model 460B can be quickly and easily converted to operate
f r o m a nominal 230 volt
50/1000
cps power source.
ment i s normally supplied with the dual p r i m a r y windings of the
power t r a n s f o r m e r connected in parallel for 115 volt operation.
To convert for 230 volt operation, reconnect the p r i m a r y windings
in s e r i e s a s shown on the schematic diagram.
The line fuse
F1
m u s t a l s o be changed f r o m 0.8 a m p slow-blow to 0.4 amp slow-
blow,
The instru-
4-5
TROUBLE SHOOTING
Low gain, low output, and impaired frequency response a r e all
directly related to tube mutual conductance and power supply out-
put voltage.
Consequently, should any of the above symptoms ap-
p e a r , the power supply output voltages should be checked (para.
4-3) and the tubes should be checked (para.
4-2).
Impaired frequency response, low gain, a n d / o r excessive hum
c a n also be caused by open o r shorted coils and by defective t e r -
minating r e s i s t o r s o r s c r e e n r e s i s t o r
s.
If
Bt
fuse
F2
blows, look for a B t short, loss of bias, o r a shorted
5654 tube,
If a 5654 tube was responsible for the blown fuse, check
the appropriate s c r e e n r e s i s t o r and r e s i s t o r R1 for possible damage.
R e s i s t o r R1 is made up of five
980
ohms r e s i s t o r s connected in
parallel.
Any one of these r e s i s t o r s could open without greatly
affecting the ope rating voltage
s
,
The cans of electrolytic capacitors C22, C23, and C24 a r e insu-
lated f r o m the chassis.
c h a s s i s the bias voltage will also be shorted.
normally not more than about 10 volts and is not dangerous to p e r -
sonnel, but tube damage
cm
r e s u l t i f this voltage i s removed,
If these capacitors a r e shorted to the
The bias voltage is
4-6
REPLACEMENT
OF 200
OHM CABLE CONNECTOR
1,
Cut 200 ohm cable to length desired,
a point where shielding and outer insulation a r e even with
the end of a center canductor support bead.
cable length to tip of banana plug will be approximately 1/4"
s h o r t e r than t r i m m e d cable length.
T r i m end of cable to
After assembly,
-10-
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