4-4 230 VOLT OPERATION
The @ Model 460B can be quickly and easily converted to operate
from a nominal 230 volt 50/1000 cps power source. The instru-
ment is normally supplied with the dual primary windings of the
power transformer connected in parallel for 115 volt operation.
To convert for 230 volt operation, reconnect the primary windings
in series as shown on the schematic diagram. The line fuse F1
must also be changed from 0.8 amp slow-blow to 0.4 amp slow-
blow,
4-5 TROUBLE SHOOTING
Low gain, low output, and impaired frequency response are all
directly related to tube mutual conductance and power supply out-
put voltage. Consequently, should any of the above symptoms ap-
pear, 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, and/or excessive hum
can also be caused by open or shorted coils and by defective ter-
minating res is tors or screen resistor s.
If Bt fuse F2 blows, look for a Bt short, loss of bias, or a shorted
5654 tube, If a 5654 tube was responsible for the blown fuse, check
the appropriate screen resistor and resistor R1 for possible damage.
Resistor R1 is made up of five 980 ohms resistors connected in
parallel. Any one of these resistors could open without greatly
affecting the ope rating voltage s ,
The cans of electrolytic capacitors C22, C23, and C24 are insu-
lated from the chassis. If these capacitors are shorted to the
chassis the bias voltage will also be shorted. The bias voltage is
normally not more than about 10 volts and is not dangerous to per-
sonnel, but tube damage cm result if this voltage is removed,
4-6 REPLACEMENT OF 200 OHM CABLE CONNECTOR
1, Cut 200 ohm cable to length desired, Trim end of cable to
a point where shielding and outer insulation are even with
the end of a center canductor support bead. After assembly,
cable length to tip of banana plug will be approximately 1/4"
shorter than trimmed cable length.
-10- |
ACEC
