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C OUTPUT OF DC
POWER SUPPLY (PS503) TO
JUNCTION OF CR245 AND R223i
CONNECT - TO ANODE OF CR245
CONNECT A DVM BETWEEN
THE + LEAD OF THE PS503
AND THE - LINE REFERENCE
WARNING I
TURN OFF ALL POWER BEFORE ATTEMPTING TO
SOLDER OR REPLACE COMPONENTS OR TO MAKE
RESISTANCE MEASUREMENTS.
EXERCISE E/A (ERROR AMPLIFIER)
TO VERIFY THE FUNCTIONAL OPERATION OF THE PWM
(PULSE-WIDTH MODULATOR) COMPARATOR, EXERCISE
THE ERROR AMPLIFIER OUTPUT AND THE SLOW START
INPUT. USE THE NODE BETWEEN R845 AND R847 AS A
SOURCE OF + 1 .6 V TO DRIVE THE COMP (PIN 9) AND
SOFT START (PIN 8) INPUTS OF U233 IN THE FOLLOW
ING MANNER:
1.
MONITOR THE DRIVE W AVEFORMS TO THE GATES
OF PWM FETS Q424 AND Q421 TO OBSERVE THE
CHANGES THAT OCCUR.
2.
CONNECT THE + 1 .6 V LEVEL TO PIN 8 OF U233.
CHECK THAT THE DRIVE W AVEFORM DUTY CYCLE
DECREASES
FROM
APPROXIMATELY
45%
TO
APPROXIMATELY 15%. MEASURE THAT THE DC
VOLTAGE ON PIN 9 OF U233 IS APPROXIMATELY
0.7 V MORE POSITIVE THAN PIN 8 OF U233.
3.
MOVE THE + 1 .6 V LEVEL TO PIN 9 OF U233. CHECK
THAT THE DRIVE W AVEFORM DUTY CYCLE AGAIN
DECREASES
FROM
APPROXIMATELY
45%
TO
APPROXIMATELY 15%.
Summary of Contents for 2440
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Page 91: ...Theory of Operation 2440 Service 3 49 Figure 3 5 Simplified CCD architecture ...
Page 120: ...Theory of Operation 2440 Service Figure 3 10 DC Restorer 3 78 ...
Page 130: ...Theory of Operation 2440 Service 3 88 ...
Page 136: ...Theory of Operation 2440 Service Figure 3 15 PWM Regulator and Inverter 3 94 ...
Page 138: ...Theory of Operation 2440 Service Figure 3 16 PWM switching waveforms 3 96 ...
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Page 423: ...2440 Service Figure 9 4b 2440 Block diagram part 2 6330 27 BLOCK DIAGRAM PART 2 ...
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Page 428: ...2440 Service WAVEFORMS FOR DIAGRAM 1 6 2 8 5 3 2 ...
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Page 432: ...2440 Service WAVEFORMS FOR DIAGRAM 2 BUS ISOLATED 6 6 0 3 4 9 ...
Page 433: ...WAVEFORMS FOR DIAGRAM 2 ...
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Page 450: ...2440 Service WAVEFORMS FOR DIAGRAM 8 6603 27 ...
Page 455: ...W A V EFO R M S FOR D IAG RAM 11 WAVEFORMS FOR DIAGRAM 11 6603 29 ...
Page 458: ...WAVEFORMS FOR DIAGRAM 12 ...
Page 463: ...WAVEFORMS FOR DIAGRAM 14 ...
Page 471: ... C N i u i t e x r 4 j u J l i 1 i 6 28 5 44 WAVEFORMS FOR DIAGRAM 18 ...
Page 476: ...WAVEFORMS FOR DIAGRAM 20 ...
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Page 502: ...2440 Service FIG 1 C A B IN E T ...
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Page 510: ...2440 Service SISSVHO Z Old ...
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Page 512: ...A12 2440 Service F IG 3 C IR C U IT BOARDS ...
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Page 517: ...10 16 R E V J U L 1993 Replaceable Mechanical Parts ...
Page 518: ...2440 Service ...
Page 519: ...FIG 4 L V H V PWR SUPPLY ...
Page 520: ...FIG 5 ACCESSORIES 2440 Service ...
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