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Section V
jumper location). If 3300A operation is normal with this
plug mated with J6, the trouble is in the plug-in unit.
Figure 5-7. Malfunction Isolating Plug
5-56.
PRECAUTIONS.
5-57.
In the event the -20 volt supply is inoperative, the
oven heater should be disabled while troubleshooting. A
point to disable the oven is to disconnect the smaller
diameter red wire (26 gage) from XA12 Pin 1. The larger
No output either channel. Power Lamp lit.
Output on only one channel.
Frequency incorrect. Specific range.
Two of the three functions normal, only
one channel effected.
Frequency and symmetry incorrect at
low end of dial, all ranges.
Frequency will not vary with FREQ dial.
No sync output.
Power supply voltage incorrect.
Frequency out of tolerance on 1 or 2
ranges which are not adjacent.
Distortion at 100 kHz.
Dc level off on square wave.
Symmetry erratic at low frequencies.
Lower half of sine wave clipped on one
channel only.
Will not oscillate.
Table 5-4. Troubleshooting Aid
SYMPTOM
diameter redwire (22 gage) should be left connected to
XA12 Pin 1. When the -20 volt power supply is left out,
the oven remains in full heat condition. Thermal fuse
A11F1 will melt and open if this heat condition exists for
any extended period.
5-58.
When troubleshooting Power Supply Assembly,
remove the Output Amplifier Assemblies A15 and A16.
5-59.
TROUBLESHOOTING TREE.
5-60.
In the event of a malfunction which causes the
oscillatory system to cease functioning; the output of the
triangle integrator emitter follower would most likely
stabilize at either one of voltages as indicated in Figure
5-8. Approximately +25 volts is the upper limit of the
positive slope, and -2.5 volts is the lower
POSSIBLE CAUSE
Use Figure 5-8 Troubleshooting Tree.
Check applicable amplifier board A15
CHANNEL A or A16 CHANNEL B.
Check feedback capacitor of effected
range on Triangle Integrator A12; for
example, Range X100 check C10, C11,
and C12.
Check input resistor of missing function;
on amplifier assembly; for example, no
SINE on CHANNEL A. Check A15R1.
Check oven heating voltage J6 pin 42
20 volts.
Check Freq shorting bar rear chassis;
A11Q5 and associated circuit parameters.
Check A14C7, A14R46 and A14R48.
Begin troubleshooting by substituting a
well-regulated 12.1 volt source for A11CR1.
Remove Output Amplifiers when trouble-
shooting Power Supply.
Change A11Q8. Use caution in soldering
and use a clip-on heat sink.
Check A13Q1.
Check A14CR18 for open.
Check A14Q8.
Check A15Q5 or A16Q5.
Check Triangle Integrator A13Q1 thru
A13Q3.
5-8
Model 3300A
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Table of Contents
Troubleshooting
