Variable Symmetry Problems; Circuitguides; Power Supply Guide; Current Source Guide - Wavetek 193 Instruction Manual

6.4.2 Current Source Guide
Top of Dial Check: Set the controls as follows; then
perform the checks in table 6-4.
Control Setting
FREO/STARTFREO 2.0
FREO MULT 1K
VERNIER FREO CAL
SYM Off (extended)
(a) Measured between + 15V and -15V supplies.
(b) Measure and note + 15V supply (V + 15)'
(c) -15V supply
= -
IV +15 ± .OWI·
1.5 Vac 10 mV ± 1.15 Vdc -23V
Maximum Maximum
Regulator Regulator
Input Output
Voltage Ripple Ripple
Supply Tolerance
(p.p)
(pop)
± 15V Balance 30 ± 1.5 Vdc -
-
(a)
+15V (b) 1.5 Vac 10 mV
-15V (c) 1.5 Vac 10 mV
+5V
±750 mV 1.5 Vac
10 mV
-5V
±750 mV 1.5 Vac 10 mV
+23V ± 1.15 Vdc 1.5 Vac 10 mV
Table 6·3. Power Supply Checks
6.4.1 Power Supply Guide
1. To determine a faulty power supply, check for
the voltages given in table 6-3.
2. If the regulator input is bad, remove P5 and
check for:
a. Shorted or open diodes (CR1, CR2, or CR3).
b. Shorted or open capacitors at the input of
the regulator.
c. Short between the regulator metal mount-
ing tab and chassis ground.
3. If the regulator input is good, check for:
a. Shorted or open capacitors at the output of
the regulator.
b. Short between regulator metal mounting
tab and chassis ground.
c. Excessive loading by main board circutts;
to verify, lift jumper of the appropriate
supply.
d. If all of the above conditions appear nor-
mal, replace the voltage regulator.
Current Source
6.4.2
Loop Delay Compensation
6.4.3
Current Switch
6.4.4
Hysteresis Switch
6.4.5
Triangle Buffer
6.4.6
Zero Crossing Detector
6.4.7
Sync
6.4.8
Capacitance Multiplier
6.4.9
Trigger
6.4.10
Trig Baseline
6.4.11
Square Shaper
6.4.12
Sine Converter
6.4.13
Preamplifier
6.4.14
Output Amplifier
6.4.15
6-10
Power Supply 6.4.1
Circuit Guide Paragraph
Functional block isolation:
1. Verify power supply voltages within
±
5% of
nominal with less than 100 mVp-p of ac ripple. If
not, refer to paragraph 6.4.1.
2. When the voltage at the right leg of R88
(VERNIERISYMCW) is -15V and when the volt-
age at the left leg of R88 (VERNIERISYM) is
- 15V, refer to paragraph 6.4.2. If not, check R88
and SW8.
6.4 CIRCUIT GUIDES
Circuit guides provide listings of voltage levels, wave-
forms, and hints that, when used with the schematics,
are helpful in isolating faulty circuits. Table 6-2 is an
index of circuit guides.
Table 6-2. Circuit Guide Index
c) U2 pin 6 should vary from - 1.0V to
+
1.0V.
(Drifting of this voltage is typical because of
constant compensation by U2 of variations in
output transistor currents.)
3. If none of the above conditions apply, refer to
paragraph 6.4.15.
6.3.15 Variable Symmetry Problems
Improperly set controls:
1. SYM button is incorrectly extended.
2. Note:When SYM is depressedthe output frequency
should be one-tenth the selected frequency.
3. DC offset is overdriving the output amplifier.