TM 9-6625-1753-14
C1
Table 2-5. Dual Trace Plug-in 79-02A. Check Procedures (Nonperiodic)--Continued
Table 2-5. Dual Trace Plug-in 79-02A. Check Procedures (Nonperiodic)--Continued
Step
Operation
Normal Indication
Corrective procedure
Step
Operation
Normal Indication
Corrective procedure
5.
Check amplifier balance-Continued.
7.
Check the output current adjustment-Continued.
Adjust the OUT CUR ADJ con-
Note. A voltmeter with a sensitivity of at least 20,000 ohms per volt is required for steps 6 through 11.
trol.
d.
Disconnect the negative lead for the voltmeter form Q(9511 and connect it to the collector of Q9514.
6.
Set the X10 amplifier dc output level.
The voltmeter indicates + 15 volts.
Readjust the OUT CUR ADJ con-
Note. The X10 amplifier gain level is misset while performing step 6. This gain level will be correctly set
trol to reduce the error by one
when performing step 8.
half (Example-the voltmeter in-
a. Set CH1 X10 cal control R9254 fully counterclockwise.
dicates 14 volts; adjust the OUT
b. Connect voltmeter, adjusted to measure 50 volts DC, between the collectors of Q9211 and Q9212, with the
CUR ADJ control for an indica-
positive lead connected to Q9211. Use the polarity switch on the voltmeter as necessary to measure the voltage.
tion of 14.5 volts.)
e.
Connect the voltmeter between the collector of Q9511 and the + 10v bus.
The voltmeter indicates zero volts.
Adjust the CH1 POSITION control.
The voltmeter indication deviates from +15 volts by an amount equal and opposite to that established in
c. Disconnect the common voltmeter lead from Q9212 and connect to a ground bus.
the corrective procedure of d above.
d. Note the position of the trace, and note the indication on the voltmeter.
Readjust the OUT CUR ADJ con-
e. Pull the CH1 VARIA BLE control to the PULL X10 position and reposition the trace to, the position noted in d
trol.
above.
f.
Repeat d and e above until the measured voltages deviate from + 15v by an equal and opposite amount.
g.
Disconnect the voltmeter.
The voltmeter indicates the same value as noted in d above.
Adjust CH1 X10 level control
8.
Perform the X10 amplifier gain adjustments.
f.
Disconnect the voltmeter and push in the CH1 VARIABLE control.
g.
Set CH2 X10 cal control R9454 fully counterclockwise.
b. Set controls as follows:
h.
Connect the voltmeter between the collectors of Q9411 and Q9412 with the positive lead connected to Q9411.
VARIABLE control (CH1 and CH2 ................ CAL, X1 (pushed in)
The voltmeter indicates zero volts.
Adjust the CH2 POSITION con-
DC-AC-GND switch (CH1 and CH2 ....................................... AC
trol.
TRIGGER switch ............................................................NORM
i.
Repeat c through f above, using CH2 controls and CH2 X10 level control R9463.
MODE switch..................................................................... CH1
j.
Disconnect the voltmeter.
c.
Apply a signal with an amplitude of between 1 and 10 volts and a frequency of 50 to 400 cycles (a filament
voltage will be satisfactory) to the CH1 MEG 14 PF connector.
7.
Check the output current adjustment.
a. Check that switch settings are established as follows:
Note.
If a signal which can be controlled in amplitude is available, adjust the signal level instead of the
MODE switch............................................................... CH2
VARIABLE control in d below.
TRIGGER switch ......................................................NORM
d.
Adjust the VOLTS/DIV switch and VARIABLE control to obtain deflection of 0.4 divisions on the CRT overlay.
Adjust the POSITION controls as necessary to determine that the signal amplitude is correctly set.
b. Connect a voltmeter, adjusted to measure 100 volts DC, between the collectors of Q9511 and Q9514, with the
e.
Without disturbing the setting of the VARIABLE control, pull the control to the PULL X10 position.
negative lead connected to Q9511.
f.
Adjust CH1 X10 cal control R9254 to obtain 4 divisions of CRT deflection.
g.
Repeat c through f above using CH2 correctors and controls, and adjusting CH2 X10 cal control R9454.
The voltmeter indicates zero volts.
Adjust the CH2 POSITION con-
h.
Disconnect the signal source.
trol.
9.
Check the trigger generation circuits dc level.
a. Set the TRIGGER switch to NORM and the MODE switch to CH1.
Note. c through e below are preliminary settings. Refer to f below for the final setting.
b. Connect a voltmeter between J9001-25 and ground.
c.
Disconnect the positive lead for the voltmeter from Q9514 and connect it to +100v test connector TP1101 on the
main frame.
The voltmeter indicates +15 volts.
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