eXact 240 - 2.5 Resistance and DC Voltage Charts

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SECT ION I I
------------------------------------------------- Mh lNTEN NCE
2.5
2 • 4 • 1 p 0 1 ER :.; up p Ly ( c ON T I N u ED )
(c) S HORTED RECTIFIER DIODES MAY CA USE FUSE BLOWING.
2.4. 2 S QU~ RE W VEFORM
V10 5 GENERATES THE SQUARE WA VEFO RM . T~E FLIP TIME JS DE-
TERMINED BY THE TRI AN GLE WA VEFORM PRESENT AT THE GRID (PIN # 9
OF V105) WHICH IS DERIVED FROM V102 CATHODE FOLLOWER. PROB-
LEMS INVOLVING SQU ARE WA VEFORM ONLY SHOULD BE TRACED TO V101
AND V105 IN TH AT ORDER. IF EXPERIENCING AN UNSYMMETRICAL
SQU ARE WA VEFORM, VERIFY THAT THE TWO S YMMETRY AD JUSTMENTS R111
AND R120 ARE CORRECT (SE E PAR A GRPH 3.2.4).
2.4.3 TRI A NGLE WAVE FORM
V1 02 IS A MILLER INTEGRATOR. THE INTEGR ATOR INPUT IS A
SQUARE WA VEFORM FROM V1018. THE INTEGR ATOR OUPUT IS A POSI-
TIVE A ND NEG AT IVE GOING VOLT A GE IN THE FORM OF A TRIANGLE.
PROBLEMS INVOLVING TRIANGLE ONLY SHOULD BR TR ACED TO V1038,
V1 02 , R133 AND R105 SETTING S IN TH AT ORDER.
2.4.4 S INE W~ VEFORM
V1 04 SHAPES THE TRI A NGLE WAVEFO RM INTO A S INE WA VEFORM. THIS
SHAP ING DEPENDS ON ACCUR A TE SYMMETRY OF THE SQU ARE AND TRI-
ANGLE WA VEF O RMS. THE INPUT DC LEVEL AND AMP LITUDE OF THE
TRIANGLE WAVEFORM ARE CRITIC A L.
LL PREVIOUS SETTINGS A ND
CALIBR A TION P R OCEDURES SHOULD BE CHECKED BEFORE FURTHER
TROUBLESHOOTING OF THE SINE WAVEFORM. ONLY THEN SHOULD PROB-
LEM S BE TRACED TO V103 , V102, S INE S HA PE A DJUSTMENTS (R139,
R143 AND R145) A ND SINE DC L EVE L R154 IN THA T ORDER.
2.4.5 DC LEV ELS
INCORRECT DC LEVELS OF OUTPUT WAVEFORMS MAY BE CA USED . BY JN-
~O RR ECT INTERN AL DC LEVEL A DJUSTMENTS ( SEE P ARAG RAPH 3.5).
RESI S T A NCE A ND DC VOLT AGE CH riRT S
2.5.1 PO WER S UPPLY RE S I STA N CE A ND DC VOLT AGE CH AR T
(
A) RESISTANCE MEASUREMENTS
THE RESISTANCE ME A SUREMENTS WERE MA DE ON A COLD INSTRUMENT
WITH CONTROLS SE T AS FOLLOWS:
M ULTI PL I ER
CYCLES/SEC DIAL
AT TENU AT OR
PO w ER OFF -ON
100
10
FULL C
1
J
OFF