Sine Wave Distorted Or Missing - Wavetek 193 Instruction Manual

6-3
Functional block isolation:
1. Verify power supply voltages are within ± 5% of
nominal, with less than 100 mVp-p of ac ripple. If
not, refer to paragraph 6.4.1.
2. Check the triangle for nonlinearity at FUNC OUT.
If it is nonlinear, but only on one range, check for
a leaky capacitor on that range. If the triangle is
nonlinear on more than one range, check for a
leaky capacitor or faulty active component in the
frequency multiplier and triangle buffer circuits.
(NOTE: Some nonlinearity above 200 kHz is nor-
mal and not specified.)
3. If the waveform is bad in one or more of the four
lowest ranges (.1, 1, 10, 100), but the remaining
ranges are normal, refer to paragraph 6.4.9.
4. Verify that square wave symmetry, at FUNC OUT,
is in specification. If not and cannot be calibrated,
refer to paragraph 6.3.10.
5. If none of the above conditions apply, refer to
figure 6-3.
6.3.5 Sine Wave Distorted or Missing
Improperly set controls:
1. SYM button depressed
2. Excessive dc offset overdriving output amplifier.
Functional block isolation:
1. Verify power supply voltages are within ± 5% of
nominal, with less than 100 mVp-p of ac ripple. If
not, refer to paragraph 6.4.1.
2. If the waveform is bad in one or more of the four
lowest ranges (.1, 1, 10, 100), but the remaining
ranges are normal, refer to paragraph 6.4.9.
3. If symmetry is not in specification and cannot be
calibrated refer to paragraph 6.3.10.
4. If none of the above conditions apply, refer to
figure 6-2.
6.3.4 Square Wave Distorted or Missing
Improperly set controls:
1. SYM button depressed.
2. Excessive dc offset overdriving output amplifier.
OUT, is out of specification and cannot be cali-
brated, refer to paragraph 6.3.10.
6. If none of the above conditions apply, refer to
figure 6-1.
Functional block isolation:
1. Verify power supply voltages are within ± 5% of
nominal, with less than 100 mVp-p of ac ripple. If
not, refer to paragraph 6.4.1.
2. Check for a nonlinear triangle. If the triangle is
nonlinear on only one range, check for a leaky
capacitor on that range. If the triangle is nonlinear
in more than one range, check for leaky capaci-
tors or faulty active components in the frequency
multiplier and triangle buffer circuits.
3. If the waveform is bad in one of the four lowest
ranges (.1, 1, 10, 100), but the remaining ranges
are normal, refer to the capacitance multiplier
guide 6.4.9.
4. If the waveform is bad only in 1M or 10M FREQ
MULT positions, refer to paragraph 6.4.3. If the
delay compensation circuit appears normal, refer
to figure 6-1.
5. If square wave symmetry, measured at FUNC
6.3.3 All Waveforms at FUNC OUT Distorted or
Missing
Improperly set controls:
1. OUTPUT ADEN or AMPLITUDE controls incor-
rectly set too low for scope gain or voltmeter
range.
2. FUNCTION switch incorrectly set to DC or AM.
3. MODE switch incorrectly set to TRIG or GATE.
4. SYM or DC OFFSETbuttons depressed.
6.3.2 Power Supply
>
100 mVp·p Ripple or Out of
Specification
1. Check line voltage selector for correct position.
2. If the supply is OV,check for a short between the
faulty supply and ground by lifting the jumpers at '
rear of the board.
3.
Lift P5 from the board. If the voltages at P5 are not
close to the values shown on the schematic table,
inspect the transformer and power receptacle. If
the voltages are normal, connect P5, then lift the
jumpers (rear of board) for faulty supply. If the
supplies are still bad, refer to paragraph 6.4.1. If
not, the problem is caused by an excessive cur-
rent drain by the generator circuits.
3. Disconnect P5. If ac voltages are now correct,
refer to the power supply guide, paragraph 6.4.1.
If not, inspect the transformer and power
receptacle.