HP 6235A - Line Voltage Option Conversion; Operation

i
Figure 3-1. Controls and Indicators
+6V supply s output voltage. With no load connected, vary
the +6 VOLTAGE control © over its range and check
that the voltmeter 0 responds to the control setting.
c. Monitor the +18V supply's output voltage. With no
load connected, vary the ±18 VOLTAGE control © over
its range and check that the voltmeter responds to the
control setting.
d. Monitor the —18V supply's output voltage. Turn
TRACK VOLTAGE © control fully clockwise. With no
load connected, vary the ±18 VOLTAGE control © over
its range and check that the voltmeter responds to the con¬
trol setting,
e. Monitor the ±1 8V output and adjust ±18 VOLTAGE
control for +18V indication on voltmeter. Monitor the
-18V output and check the effect of the TRACK VOLTAGE
control on the voltage of the -18V output. The -18V out¬
put should be adjustable from less than 0.5 volts to a maxi¬
mum of 1 8 to 21 volts as the TRACK control is rotated
from its fully CCW to its fully CW position.
f. Turn the +6, ±18, and TRACK VOLTAGE controls
fully CW. Connect ammeter (e. g. Simpson Multimeter,
Model 269), in turn, between each output and COM. The
internal resistance of the meter is low enough to overload
the supply so that the output will current limit. Verify that
the current limit circuit in each supply is limiting the output
current to:
Supply
Current Limit
+6 V
1.275A ±15%
+18V
0.255A ±15%
-18V
0.255A ±15%
g. R e m o ve meter and connect loads to the output ter¬
minals (see paragraph 3-23).
3-1 2 If this brief checkout procedure or later use of the
supply reveals a possible malfunction, see Section V of this
manual for detailed test, troubleshooting, and adjustment
procedures.
3-13 LINE VOLTAGE OPTION CONVERSION
3-14 To convert the supply from one line voltage option
to the other, proceed as follows:
T Disconnect line cord from the power source.
2 . Remove top cover from supply by removing
2 screws in rear of supply and sliding cover to the rear. The
line voltage selector switch (S2) is mounted on the circuit
board behind the meter.
3. Set S2 to the desired position (see Figure 3-2).
The forward switch position (toward front panel) selects
120 V ac input and the rear switch position (toward heat
sink) selects the 240Vac input.
4. Check the rating of the installed fuse and
replace it with correct value, if necessary. For 120Vac
input, use a 0.4A slo-blow fuse (HP Part No. 2110-0340).
For 240Vac input, use a 0.2A slo-blow fuse (HP Part No
2110-0235).
5. Install proper line cord and plug (see paragraph
2 - 2 1 ) .
6. Mark the supply clearly with a tag or label
indicating the correct line voltage to be used.
3-15 OPERATION
3-16 This power supply can be operated individually or
in parallel with another supply (see paragraph 3-27). All
output terminals are isolated from chassis ground. The ±6V
and ±1 8V outputs use a single common output terminal ©
This common (COM) terminal or any one of the other out¬
put terminals may be grounded to the chassis ground termi¬
nal which is located on the supply's rear heat sink. All out¬
puts may also be left floating. Loads can be connected
separately between each of the 0 to 18V output term inals
and the COM terminal, or between the +18V and —1 8V
terminals for a 0 to 36V output. A single load can also be
connected between the ±6V and -18V terminals for a 0
to 24V output.
Figure 3-2. Line Voltage Selector (Set For 120Vac)
3-2