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Table 6·2. Power Supplies and Generator Loop (Continued)
Indication: Fuse blown, no power indication or no outputs.
7.
Check U7 pin 14 for + 5 Vdc and U7 pin 13 for - 5 Vdc.
8.
Check U4 pin 13 for a dc shift from approximately + 10V to + 15V as the
frequency dial is rotated from 4.0 to .004. Check U6 pin 8 or a dc shift from
- 10V to - 15V as the frequency dial is rotated from 4.0 to .004.
9.
Check anode CR6 for approximately + 3.5 Vdc.
If emitter 011 has a 4 kHz,
10.
11.
Check for the same voltage at the gate of 09 as at the emitter of 011,
within saturation limits of the amplifier.
12.
If the voltage at the emitter of 011 is � + 1.25V, check cathode CR10
for approximately - 2.5V. If the voltage at the emitter of 011 is
check cathode CR1 0 for approximately + 2.5V.
13.
Check U5.
Indication: Function outputs missing or clipped when TTL sync output OK. Problem with triangle waveform.
1.
Set controls to initial positions (refer to paragraph 6.4).
2.
Check emitter 011 for a 4 kHz,
3.
Select triangle function, rotate AMPLITUDE ccw, and check U13 pin 10
for a ± 1.25V triangle.
4.
Rotate AMPLITUDE cw (MAX), DC OFFSET to OFF, and check 50n OUT
(HI) for a 20V p-p (open circuit) triangle.
5.
Check for excessive discontinuities at the triangle peaks near the bottom
of a frequency range (other than x 1 to X 100).
6.
Check for nonlinearities in the triangle slopes near the bottom of a fre
quency range (other than x 1 to X 100).
7.
Check for a waveform symmetry problem.
Check
±
1.25V triangle, go to table 6-3.
Table 6·3. Output Circuits
Check
±
1.25V triangle.
If Faulty, Check
a. 04, 03, U2.
b. Excessive
board jumpers to isolate
cause.
Go to table 6-7.
Go to table 6-10.
09 - 011 and associated
circuitry.
.
U7,
07
and
- 1.25V,
circuitry.
:5
If Faulty, Check
Check for normal operation.
Go to table 6-2.
a. R114, R112 adjustments.
b. U13.
c. SW13.
a. Output amplifier circuit.
b. E15, E16 wiring.
a. U5.
b. SOR
signal
±
CR10 not
a. Associated timing capaci
tor or C36.
b. U5, CR6.
c. 09, 010.
Go to table 6-8.
loading;
use
associated
at
cathode
2.5V.
6-3
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