R2 on the dc voltmeter should be 1.3 volts
0.26 volt dc.
i. Repeat the procedure given in d through
a. Set the COARSE ADJ. and the FINE
h above for passing stage resistors R3
ADJ. controls on the front panel until the pan-
locate the negative meter lead test point.
b. Set the POWER switch to OFF.
j. Reduce the load current to 2 amperes by
c. Remove all links from the unit (front or
unscrewing the lamp bulbs until panel meter
rear) and turn the POWER switch to ON.
M1 indicates 2 amperes.
d. The panel voltmeter (M2) should show
k. Check the ac input at the variac for a
level of 115 volts ac. Adjust the variac if nec-
a reading of 36 volts dc 2.
Checks Under Load
l. Adjust the COARSE ADJ. and the FINE
ADJ. controls for a panel dc meter (M2) in-
Connect the equipment and set the front
dication of 36 volts dc. Check panel ammeter
panel controls as indicated in paragraph 6.5.
M1 for a 2-ampere indication.
Prepare a load for testing the power supply.
changing the lamp bulb loads if it is neces-
Note : A suitable load for the power supply can be
built by using a set of standard 150-watt lamp bulbs
m. Prepare the dc voltmeter for a volts
connected in parallel. Use a bank of approximately
range of 50 volts dc.
nine lamps. Change the load by unscrewing them.
n. Check the voltage across the capacitors
a. Add a resistive load to the power supply
listed in the chart below:
output terminals of 2 amperes.
Note: One 150-watt lamp gives a load current (on
dc meter M1) of approximately 750 milliamperes. The
four lamps connected in parallel should load the sup-
ply close to the required 2 amperes. Use a total of
nine lamps in the test load setup. Change the load
Note: Be careful when handling the component boards
by unscrewing the lamps as needed or screwing them
during these tests to avoid damage to the transistors.
back as needed.
Rear Terminal Measurements and
b. Set up the dc voltmeter to a volts range
of 500 volts dc.
c. Connect the dc voltmeter test leads across
Connect the equipment and set the controls
filter capacitor C1; observe the proper polar-
d. Adjust the variac to provide an input of
and connect the suitable shorting links to the
115 volts ac to the power supply.
e. The dc voltmeter should indicate a read-
a. Perform the test procedure as outlined in
ing of 58 volts dc 5.8.
f. Remove the dc voltmeter test leads from
instead of the front binding posts. (Refer to
C1 and connect the leads across resistor R2
quirements to the rear terminal strip.)
the negative voltmeter lead to the emitter end
b. Be sure that all connections to the termi-
of Q1 (right side of the resistor as seen on
nal strip are mechanically tight when making
g. Increase the load by screwing in lamp
c. Disconnect all test equipment and re-
bulb loads until panel meter M1 indicates a
store the power supply unit to its normal op-
load current of 4 amperes.
h. The dc voltage drop as indicated across