C irc u it D e s c rip tio n —434
backplate voltage is gradually returned, the target is charged
to the rest p o te n tia l and the target is in the ready-to-w rite
state.
For a comprehensive stu d y o f storage tube operating
principles, a T e k tro n ix C irc u it Concepts paperback book
e n title d "Storage C athode-Ray Tubes and C irc u its " is
available through y o u r local T e k tro n ix , Inc., Field O ffic e or
representative. T e k tro n ix S tock No. 062-0861-00.
Flood Guns and C o llim a tio n Electrodes
T w o low-energy electron guns, or flo o d guns, are used in
the 434. The cathodes are returned t o —75 volts through
IN T E G R A T E sw itch S94 and R94. R 1298 and VR 1298 set
the level o f the flood-gun c o n tro l grid at a p p ro xim a te ly
+ 140 volts.
Fig . 3 -1 8 . S e c o n d a ry em issio n curve.
w ritte n . Thus, com plete w ritin g is a fu n c tio n o f w ritin g
beam c u rre n t density.
When the stored display is no longer desired, the in fo r
m ation is erased by a waveform as illu stra te d in Fig. 3-19. A
positive-going pulse is firs t applied, to raise the backplate
voltage above the w ritin g threshold and w rite th e e ntire
target area w ith flo o d gun electrons. N e xt, the backplate
voltage is pulled w e ll below the rest p o te n tia l, then as the
F ig . 3 -1 9 . T y p ic a l erase c y c le w a v e fo rm .
The c o llim a tio n electrodes serve as an electrostatic lens
to d is trib u te the flo o d gun electrons u n ifo rm ly over the
storage target, and they have no e ffe c t on the landing
energy o f the electrons. R 1293 and R 1925 determ ine the
voltage levels o f CE1 and CE2 through e m itte r fo llo w e rs
Q 1294 and Q 1296 respectively. R 1292 is an a d d ition a l
C R T G eom etry adjustm ent.
Target C o n trol A m p lifie rs
The Target C o n tro l A m p lifie rs are in corporated to m ain
ta in a high degree o f c o n tro l o f the upper and lower storage
backplate voltages. These are e m itte r-fo llo w e r feedback
am p lifie rs consisting o f Q 1230, Q 1232, and Q 1235 fo r the
upper target backplate and Q 1280, Q 1282, and Q 1285 fo r
the low er target backplate. A bootstra p p in g c irc u it is
provided fo r each T arget C o n tro l A m p lifie r to m aintain
transistor operating voltage d u rin g the positive-going p o r
tio n o f the erase w aveform (fade positive). The b o o t
strapping c irc u its w ill be described in fu ll detail in the Erase
Generator discussion.
A separate STORE sw itch is provided fo r each Target
C o n tro l A m p lifie r, S90B (upper) and S92B (lo w e r), a llo w
ing the target backplates to be operated in d iv id u a lly . In the
STORE m ode, th a t is, when the STORE b u tto n s are pushed
in and the CRT is shifted to the read y-to -w rite state, the
backplate voltages are adjusted in d iv id u a lly by the Store
Level controls, R 1226 and R 1276. These adjustm ents set
the value o f cu rre n t to the feedback a m p lifie r null points
(Q 1230 and Q 1280 em itters), in the non-store, or conven
tio n a l mode, the backplate voltages are established by
adjustm ent o f the N on-Store Level adjustm ents R 1224 and
R 1274.
3-27
Содержание 434
Страница 6: ...Fig 1 1 4 3 4 O scilloscope 434 ...
Страница 41: ...Fig 3 3 Channel 2 Input A m p and Preamp detailed block diagram C ir c u it D e s c r ip tio n 4 3 4 ...
Страница 51: ...F ig 3 1 1 S w e e p G e n e ra to r d e ta ile d b lo c k d ia g ra m CO C irc u it D e s c rip tio n 4 3 4 ...
Страница 55: ...C871 Circuit Description 434 ...
Страница 110: ...Rackmounting 434 3 r i C V J o o o o o s w C V J o ip w 0 r 6 4 Fig 6 6 Dim ensional draw ing MkX ...
Страница 153: ......
Страница 157: ...P O A 5 CAM SW 1TC H C H 2 4 3 S20O CH Z INPUT A M P L IF IE R P R E A M P ...
Страница 159: ...4 3 4 5 C O jiiV S O O s 0 s 2 5M S ...
Страница 160: ...434 Fig 8 9 P O A 2 Partial V ertical c irc u it board ...
Страница 161: ...434 ...
Страница 162: ... ...
Страница 170: ... MI5V 3 ...
Страница 172: ......
Страница 173: ...434 Fig 8 20 P O A10 Partial Power Supply Secondary circuit board ...
Страница 174: ...434 Fig 8 21 A l l A 12 Transformer Primary and Secondary circuit boards ...
Страница 175: ......
Страница 177: ...434 5 200 D 3 5 V ...
Страница 179: ... l D z F d s 5V m s 5 7 r JL 4 3 4 S T O R A G E ...
Страница 187: ... FIG 1 Front ...
Страница 197: ...434 R434 FIG 2 Chassis Rear Standard Accessoires ...
Страница 199: ...s g 4 ...
Страница 200: ...434 R434 STORAGE OSCILLOSCOPE FIG 3 Cabinets ...