eXact 240 - 2.4 Troubleshooting Procedure

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240-0664
SECTION II
------------------------- - ---------------------- - MrilNTENANCE
2 . 3 . 4 S INE WA VEFORM GE NER A TOR (CONTINUED)
S INE ,D J ' (R139) CONTROLS THE DC LEV EL OF THE GRID .
S
INE AD J B (R143) CONTROLS THE AMPLITUDE OF THE TRIANGLE INTO
GRID PIN # 1 OF V104 .
S I NE
AD J c (R145) coNTRo Ls THE suPPREs s oR B1 As oF v104 .
2 . 3 . 5 MA IN
OUTPUT
V106 IS A CONVENTION AL CATHODE FOL L OWER . THE PROP E R WAVEFORM
BEING FED TO THE GRID I S SELECTED BY THE OUTPUT SWITCH , SW 104 .
THE QC LEVEL OF THE CONTRO L GRID IS DETERMINED BY :
(
A) R158, R159 AND R161 IF ±DC OUTPUT LEV E L SWITCH I S CC'.,../ IN
SWITCHED POSI TIO N .
(B) R162 IF ±DC OUTPUT LEVEL SWITCH IS cw FR OM SW IT CHED P O SI -
TION .
2 .
3.6 S I MU LT ANEOU S O UT P UTS
V1 0 1 A , V1038 A ND V10 3 r ARE ST ANDARD CATHODE FOLLO WE RS PROV I D-
IN G LO W IMPEDANCE OUTPUTS FOR THE INDIVIDUAL SQUA RE , TRI A NGLE
AND S I NE WAV EFORMS . TH E SINE WA VEFORM CATHODE FOLLOWER (V103 A )
HAS A DC LEV EL CONTRO L ONLY, W HILE THE S QUARE WAVE AN D TRI ANG LE
WAVEFORM
CATHODE FOL LOWERS (V1018 AND V103ff) HAVE BOT H DC L EVEL
AND AMP LIT UDE CONTROLS·
2 . 4 TROUBLE S HOOTING PROCEDURE
2 . 4.1 PO W ER S UPPLY
( A) ALL CIRCUITS DEPEND ON T HE REGU L ATED - 210V , +1 QQV AND
+250V . THE MORE CRITIC AL GENERATING C I RCUITS ALSO DE
0
END
ON T HE - 11V FIL AMEN T REGU L A TION . A LWAY S CHEC K TH ES E SUP -
PL IES FOR CORRECT VOLT AGE A ND MINIMUM RIPPLE (BELOW 10MV
ON HIGH - VOLT A GE S UPPLI ES AND BELOW 100MV ON - 11V SUPPLY) .
(1) FOR - 210V PROB L EM S CHECK V1, V2 AND V3 ; CHE CK - 210
A DJ R23; CHECK DIODES 09 THROUGH 012 .
(
2) FOR +1 00V PROBLEM S CHECK - 210V , V3 AND V4, DIVIDER
VOLT AGE AT PIN # 1 OF V4 AND DIODES 05 THROUG H 08 .
(3) FOR + 250V PROBLEM S CHECK -210V , V5 AND V6 , DIVIDER
VOLT AGE AT PIN # 1 OF v6 AND DIODES 01 THROUGH o4 .
(4) FOR - 11V PROB LE MS CHECK Q1 , ZENER DIODE 017 AND DIODES
013 THROUGH 0 1 6 .
(B) ' .,../HE N E X PERIEN C ING HUM, DRIFT OR JI TTER , CHECK THE RE GUL A-
TION OF THE POWER SU PPLIES AND /OR INSU RE TH AT THE STRA P
I S
INSTA LL ED BETWEEN THE CHASSI S GROUND A ND THE CIRCUIT
GROUND TERM I NALS .