For a Nonstore X-Y display CR818, CR817, and
CR816 are reverse biased. The XY signal is LO to reverse
bias CR551 and allow current in R820 to flow through
CR820. The crt intensity is then controlled by the A
INTENSITY potentiometer which sets the current in R820
through Q804.
Theory of Operation— 2230 Service
During Nonstore operation, any applied External Z-Axis
input voltages drive proportional input currents through
R822 and R823 to the Z-Axis Amplifier. Sensitivity to
external signals is determined by the transresistance gain
of the shunt-feedback amplifier. Diode CR823 protects the
Z-Axis Amplifier if excessive voltage levels are applied to
the EXT Z AXIS INPUT connector. External Z-Axis modu
lation does not function for STORE MODE displays.
BEAM FIND switch S390 controls the base bias volt
ages of Q825 and Q829. When the BEAM FIND button is
out, -8 .6 V is supplied to the normal base-biasing net
work. When the button is held in, the - 8 . 6 V supply is
removed, and the voltage at the anode of VR828 rises to
about -5 .6 V. This voltage level turns off the current sup
ply from Q829. The Z-Axis amplifier output voltage is then
fixed by R835 and the voltage at the BEAM FIND switch,
as set by other parts of the Beam Find circuitry. The out
put voltage of Q835 is set to a level that displays either a
bright trace or dot (depending on whether the sweep is
triggered or not), and the INTENSITY controls and the Z-
Axis drive signals have no control over the crt intensity.
Hv Multiplier, Dc Restorer, and Crt
The Dc Restorer circuit sets the crt control-grid bias
and couples the ac and dc components of the Z-Axis
Amplifier output to the crt control grid. Direct coupling of
the Z-Axis Amplifier output to the crt control grid is not
employed due to the high potential differences involved.
Refer to Figure 3-11 during the following discussion.
Ac drive to the Dc Restorer circuit is obtained from
pin 16 of T948. The drive voltage has a peak amplitude of
about ±100 V at a frequency of about 20 kHz and is cou
pled into the Dc Restorer circuit through C853 and R853.
The cathode of CR851 is biased by the wiper voltage of
Grid Bias potentiometer R851, and the ac-drive voltage is
clamped whenever the positive peaks reach a level that
forward biases CR851.
The Z-Axis Amplifier output voltage, which varies
between + 10 V and +75 V, is applied to the Dc Restorer
at the anode of CR853. The ac-drive voltage holds CR853
reverse biased until the voltage falls below the Z-Axis
Amplifier output voltage level. At that point, CR853
becomes forward biased and clamps the junction of
3 -5 0
Figure 3-11. Simplified diagram of the Dc Restorer circuitry.
Summary of Contents for 2230
Page 12: ...2230 Service X The 2230 Digital Storage Oscilloscope 4998 01 ...
Page 33: ...Operating Information 2230 Service Figure 2 5 Vertical controls and connectors 2 6 ...
Page 48: ...Operating Information 2230 Service Figure 2 11 X Y Plotter interfacing ...
Page 56: ...Theory of Operation 2230 Service 4999 01 3 2 Figure 3 1 Simplified block diagram ...
Page 68: ...Operating Information 2230 Service Figure 2 11 X Y Plotter interfacing ...
Page 76: ...Theory of Operation 2230 Service 4999 01 3 2 Figure 3 1 Simplified block diagram ...
Page 98: ...Theory of Operation 2230 Service 499 9 06 Figure 3 6 Horizontal Amplifier block diagram 3 24 ...
Page 111: ...Theory of Operation 2230 Service 3 37 Figure 3 9 Acquisition Memory timing ...
Page 190: ...Maintenance 2230 Service 999 14 Figure 6 3 Isolated kernel timing 6 9 ...
Page 329: ...PUT Figure 9 2 S em ico n d u cto r lea d co n fig u ratio n s ...
Page 332: ...2230Service CHASSIS MOUNTED PARTS ...
Page 334: ...A14 CH 1 LOGIC BOARD ...
Page 337: ......
Page 344: ...u sr z z o 1 ...
Page 347: ...i n 5 a O Q q o u S a o h UJ s a b c d e f g h j k l m n ...
Page 352: ......
Page 355: ...WAVEFORMS FOR DIAGRAM 5 4999 83 ...
Page 358: ...I W L U O U rc a 4 2 s ...
Page 361: ...WAVEFORMS FOR DIAGRAM 6 S 84 ...
Page 362: ...2230 Service TEST SCOPE TRIGGERED ON U665 PIN 8 FOR WAVEFORMS 31 THROUGH 33 ...
Page 365: ... I I ...
Page 366: ...A 1 6 S W E E P R EFEREN CE BOARD FIG 9 17 2230 Service Figure 9 17 A16 Sweep Reference board ...
Page 369: ... o 0 UJU sa eg aiu c u J in su eg 5 C sis n g e s o N QO ...
Page 371: ...Static Sensitive Devices See Maintenance Section CM I rv CD o 2230 Service ...
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Page 384: ... I I c o C u o a 5 r O tD v j If 3 IV if I I ci if 5 3 I ...
Page 386: ......
Page 388: ...H K L M N 7 8 8 2 2 3 0 INPUT OUTFUT WIRING INTERCONNECT ...
Page 392: ...W A V E F O R M S F O R D IA G R A M 14 ...
Page 393: ...2230Service 0 0 d s t 4 9 9 9 9 5 ...
Page 394: ...2230 Service TEST SCOPE TRIGGERED ON U911 PIN 21 FOR WAVEFORMS 64 THROUGH 69 4999 92 ...
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Page 397: ...WAVEFORMS FOR DIAGRAM 15 TEST SCOPE TRIGGERED ON U9111 PIN 21 FOR WAVEFORMS 70 THROUGH 77 ...
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Page 415: ...IMF PU TPR A IR TM FQ U I W A V E F O R M SF O RO IA G R A M1 5 W A V E F O R M SF O R i ...
Page 417: ...4999 9S ...
Page 419: ...i s 5 0 C C p F 2 CC p 2 a u 4 I s c c O 2 e e o 5 a o 5 i 2 i f 2 E C 52 ...
Page 423: ...W A V E F O R M SF O RD IA G R A M1 8 O c n ...
Page 424: ...Figure 9 22 A11A1 Input Output board ...
Page 430: ...Figure 9 23 A11A2 Vector Generator board ...
Page 434: ...49 9 9 tOO ...
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Page 437: ...22 3 0 S ervice W A V E F O R M S F O R D I A G R A M 2 1 m f n h ...
Page 442: ...WAVEFORMS FOR DIAGRAM 22 4999 78 ...
Page 443: ...XY PLOTTER BOARD DIAGRAM 22 See Parts List for serial number ranges ...
Page 447: ...A21 RS 232 OPTION BOARD Flfi A 9 K 01 01 W M ...
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Page 452: ...COMPONENT NUMBER EXAMPLE ...
Page 459: ...A16 SWEEP REFERENCE ADJUSTMENT LOCATION ...
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