Table of Contents
Advertisement
Sect. IV Page 6
Table 4-1.
SYMPTOM AND POSSmLE CAUSE
b. Defective tube in main regulator.
(CCNI"D.)
c. Potential applied to tube pins
not of proper values.
d. Relay K1 held operated.
3. Instrument operating, but output
voltage
is
not at proper level.
a. Control tube V4B not operating
properly.
b. Defective component in voltage
divider.
4. Level of output cannot be adjusted
lower than 175-225 volts.
a. Short in V1 and/or V2.
5. When relayK1 is operated(current
at overload), resistor R2 burns
out.
4.10
TROUBLE LOCALIZATION
Trouble Shooting Chart (Cont' d.),
TEST PROCEDURE
(2) Check V1, V2 as follows:
A.
Check that no load is connected to d-c output ter-
minals.
B.
Remove one 6L6 and leave other in circuit.
If
trouble
clears with one 6L6 out of circuit, replace that 6L6.
c. Check d-c voltage on pins of all tube sockets: should be within
±10% of those shown in Figure 4-8.
d. Check that no load is connected to d-c output terminals. Re-
move K1.
If
voltmeter indicates the removal of K1 has cor-
rected the trouble:
(1) Check contacts on switch S2 (Figure 4-2)
(2) Check for open resistor R2.
(3) Check K1 by substituting relay known to be good.
a. Check V4 by substituting 6U8 known to be good, and
by
check-
ing
potentials on tube pins; should be within ±10% of values
shown in Figure 4-8.
b. Turn COARSE and FINE controls from max ccw to max cw,
and note voltmeter indication:
(1) At max ccw, vm should read less than zero.
(2) At max
cw,
vm should read more
than
500. Refer to para-
graph 4-3c for adjustment.
a. Check that no load is connected to d-c output terminals, re-
move one 6L6, and leave other in circuit.
If
zero output can
be obtained with one 6L6 out of circuit, replace that 6L6.
5. R2 burns out because of intermittent arc or permanent short
between K1 pin 7 (+400 to +700V) and pin 6 (-200V) when re-
lay K1 is operated.
recommended that testing to localize trouble start
with the secondary regulator.
When the cause of instrument failure or substandard
operation is of a more obscure nature than the pos-
sibilities covered
by
the trouble-shooting chart, the
failure should be localized to a section of the circuit,
and then isolated within the section. Basic sections
of the circuit are defined in Figure 4-1.
It
is
After isolating trouble to a section of the circuit
which includes more then one tube, the next step
is to determine the tube circuit involved. A re-
placement tube should be tried before attempting
Advertisement
Table of Contents
