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Theory of Operation— 2236 Service
gate an interval only when pin 14 of U1002C is HI. This is
the shorter of the two delay periods. When the firmware
wants to measure the longer delay, DmodeO is set HI, which
causes U1003D to gate an interval only when pin 14 of
U1002C is LO, thereby selecting the second delay.
__ jf the VERTICAL MODE switch is in the ALT position,
Valt is LO and U1601 gates the Ch 1 Selected signal to
U1002C. Circuit operation is identical to that described
above except that Ch 1 Selected toggles at twice the repe
tition rate of the output of U1600B.
Delay/Delta Time Controller-Analog Section
The analog section operates in one of two modes, de
pending on the level of the Dly2 signal. When Dly2 is HI,
Q1601 is biased off, which causes Q1603 to also be biased
off. Since there is no voltage drop across R1617, only the
DT Wiper signal is applied to voltage-follower U1604B
through U1604A.
If Dly2 is LO, then Q1601 and Q1603 are biased on.
Transistor Q1602 serves as a constant current source for
zener-diode VR1601. The diode voltage will be applied
across R1617 so that the
A
TIME POSITION pot wiper volt
age is then summed with the DT Wiper voltage and applied
to U1604B.
Intensified Zone Controller
Controller 1C U1603 selects the proper signal for control
ling the intensified zone. If the CTM is not set up in a gated
mode, then Barm is LO and the B Gate signal is connected
to Ctrintens. The intensified zone is not affected by the
CTM.
If the CTM is in a gated mode and the oscilloscope is in
the B Runs After Delay mode, then Brun is HI and B Gate is
coupled to Ctrintens. If the oscilloscope is in the B
Triggerable After Delay mode, then Brun is LO and the
counter gate signal (Busy) is connected to Ctrintens.
DMM
The DMM circuitry, shown on Diagrams 8 and 9, mea
sures dc volts, rms ac volts, and resistance using the DMM
leads connected on the side of the cabinet. Additionally, dc
and rms ac volts may also be measured using the CH 1 OR
X & DMM input connector. Parameter functions are chosen
using the front-panel pushbuttons and the Channel 1 Input
Coupling switch. Values are then displayed on the seven-
segment vacuum fluorescent readout.
An input switching network controls signal selection and
conditioning and its output is buffered by an amplifier with a
3-29
Summary of Contents for 2236
Page 10: ...2236 Service viii The 2236 Oscilloscope ...
Page 74: ...Theory of Operation 2236 Service 3 30 ...
Page 102: ...Performance Check Procedure 2236 Service 4 21 Figure 4 1 Test setup for DMM common mode check ...
Page 242: ...2236 Service 4204 34 Figure 9 6 CTM basic block diagram ...
Page 243: ...DMM POWER S U P P LIE S 2236 Service F ig u re 9 7 C T M d e ta ile d b lo c k diag ram ...
Page 254: ...S I 0 O I 5 1 S O i 4204 21 C IR C U IT BOARD INTERCONNECTIONS ...
Page 267: ...1 2 3 4 5 6 7 8 9 J T K L M_ _ ___ N___l _ P____l S ...
Page 271: ...1 2 3 4 5 6 7 8 9 lO P2SO O U1 A TRIGGER V T O W2500 5 A 223 R E V A P R W G ...
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Page 285: ...A 6 F IL T E R B O A R D lo c a te d u n d e r H V S h ie ld ...
Page 313: ...2236 Service T O U I 3 0 0 4 8 K T O UI300 II S K 0 2 2 3 6 Z Z O A Z 2 OPTION IA ...
Page 317: ...A 10 C O U N T E R T IM E R M U L T IM E T E R B O A R D A D J U S T M E N T LO C A T IO N S ...
Page 319: ...2236 Service TROUBLESHOOTING GUIDE 4206 99 4204 69A ...
Page 323: ...9 ...
Page 324: ...2 REV APR 1986 ...
Page 325: ...2236 SERVICE ...
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