4-10. TROUBLESHOOTING
4-11. W h e n e v e r trouble is suspected i n t h e plug-in u n i t , substitution o f a u n i t
known t o be good will provide a quick check. I f i t is determined t h a t trouble
does exist in the plug-in u n i t , t h e f i r s t step i s a check o f the +15VDC and
-15VDC. I f the output i s greatly reduced, check the oscillator operation a t the
collector or Q113. I f a square wave o f the proper frequency and amplitude i s
present, the trouble may be i n the f i l t e r. C h e c k the output o f the f i r s t f i l t e r
section a t '0106.
NOTE
If a crystal-controlled oscillator is not working,
check the crystal. Dropping t h e u n i t , o r other
rough handling may fracture the crystal.
4-12. Troubleshooting i s accomplished b y signal tracing a t the test points
shown i n Figure 5-1 a n d Figure 5 - 3 . F o r the crystal-controlled models, t e s t
for a signal a t the crystal oscillator, t h e flip-flop dividers, a square wave a t
CR103 and a sine wave a t the two filter outputs, and a t the B - and C -phase
outputs.
4-13. I f no output is present on the 0.1$ model, inject a 3 V RMS signal a t
appropriate frequency through a 3.3K resistor into pin 3 o f Z103. C h e c k f o r
6.2V peak-to-peak signal a t CR103 and f o r correct signals a t the filter and B -
and C -phase outputs.
4-14. T h e output frequency o f the 0.0001$ oscillator is adjustable b y a screw-
driver adjustment a t the top o f the oscillator module. A c c e s s is gained t o this
adjustment b y removing the top cover o f the power source. A l l o w a 30-minute
warmup period. D o not change frequency setting unless a frequency standard
of adequate accuracy i s available f o r comparison.
4-15. P H A S E -ANGLE ADJUSTMENT
4-16. T h e phase-angle adjustments are set a t the factory and should not be
disturbed unless appropriate test equipment is available t o determine the output
phase angles. I f an accurate phase-angle meter is not available, phase angles
may b e determined b y line-to-line voltage measurements. T h e front-panel v o l t -
meters in the Elgar power sources are only accurate to 1:3$ and are not suitable
for precision phase angle adjustment.
4-17. O p e n Delta Connection: S e t the two amplifier outputs ECA and E r i z t o
120V. A d j u s t B-phase, R136, until t h e line-to-line voltage EAB equals n 7 . 9 4
volts. T h e C -phase adjustment, R133, has no effect.
4-19. 3 -Amplifier Wye Connection: S e t the amplifier outputs, ENA, Skim, a n d
E . t o 120V. A d j u s t B -phase, R136, f o r line-to-line voltage equart to 2r7.94
vOIrs. A d j u s t C -phase, R133, f o r line-to-line voltage EAC equal to 207.84
volts.
4-20. 2 -Phase Connection: S e t both amplifier outputs to 120V. A d j u s t
B-phase, R136, until line-to-line voltage EAB equals 169.71 volts.
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