Section V Model 204B
Paragraphs 5-16 to 5-24
Figure
5-4. Model 204B, Exploded View
a.
Do not apply excessive heat,
b. Apply heat to component lead on conductor side
of board, and remove lead with
a
straight upward pull
.
c. Use
a
toothpick or wooden splinter to clean
holes.
d. Solder replacement components from the con-
ductor side.
5-16.
TROUBLESHOOTING.
5-17. To locate trouble in the Model 204B, start with
a
thorough visual inspection. Look for burned-out
or loose components, loose connections of any other
condition which suggests
a
source of trouble. If
a
visual inspection does not reveal the trouble, use the
block diagram, figure 4-1, and troubleshooting sum-
mary, table 5-3, ad aids for isolating the trouble. The
troubleshooting summary lists indication of and action
to
be
taken for various troubles; the action should be
taken in the order given.
PROCEDURES.
5-18.
ADJUSTMENT AND CALIBRATION
5-19. AC POWER SUPPLY CHECKS.
5-20. The
ac
power supplyvoltages are typically +13
and -13 volts, but may vary from 12 to 13. 5 volts. As
linevoltage isvariedfrom 103.5 to 126. 5 volts, supply
voltages should remain with the 12 to 13. 5 volt limit.
5-21, Ripple voltage in the
ac
power supply should be
less
than
2
mv.
To check ripple voltage, it
is
nec-
essary to connect
a
wire
from circuit ground
(h)
to
the junction of RlOA and S1D. Measure ripple voltage
as
the line voltage
is
varied from 103.5 to 126. 5 volts
.
5-22. When trouble occurs, in the
ac
power supply
check CR15 and CR16
first.
If
any repair
is
per-
formed, adjust DC BAL control (paragraph 5-26).
5-23. BATTERY CHARGER CURRENT
ADJUSTMENT.
5-24. The battery charger current
is
set at the factory
for 5.5
*O.
5 milliamperes to provide maximum battery
life,
Charge current adjustment R102 can be set to
provide
a
quick charge by increasing the charging
current to not more than
11
milliamperes.
5-25.
Use
the following procedure to set charge
current adjust R102 for quick charge operation.
a.
Remove top cover from oscillator chassis.
b. Connect power cord to
a
power source.
c. Turn oscillator
OFF.
d. Attach current probe of clip-on milliammeter to
one input lead of battery charger circuit. (See figure
e.
Set R102 for the desired charge current.
.
5-11.)
1
5-4
01369-3
To Next Page
Loading...
