Tektronix 2235 User Manual

Sync li n e will go L O at t he end of t he Α Sweep and ca
u se an

o u t p ut states, two Α Sweeps are re qu ired to cause t he
fli p -
immediate resetti n g of t he Ge
n
erato
r .
In
eit h er case, α new

flop output levels to switc h . W it h t h is switc h ing arra nge-
sweep will be initiated t he next time
t h
e
Α Swee p voltage at

ment, t h e crt will first dis p lay t h e two Α Inte n sified Swee ps
U 655 pin 3 exceeds t he voltage at pin 2 .

and
t hen t he two Alternate Β Swee p s .
Wh en n ot in t he Ru ns After Delay mode,
t h
e out
pu t of

Β Ζ -Axis L ogic
U 660A is HI and U 670A h as α HI on b ot
h t he S and D
inputs . T he circuitry con necte d to t
h
e
R input of U 670A

The ΒΖ -Axis L ogic circuit r y switc hes signal current lev-
functio ns as descri b edab ove . Wh e n t he output of U 660
F
els
to drive t he Ζ -Axis Amplifier for bot h t he Β and t he Α
goes HI, U 670A is no longer h el d r eset and t
h
e
fi r
st
Β trigger

I n tensified Swee p displays . T he c urr en t sup p lied is su mmed
signal from t he collector of Q630 will cloc k t
h
roug
h
t
h
e
ΗΙ
on

with
the ot h er signal inputs on t h eΖ -Drive line .
t he D in p ut . T h e 0 ou t pu t of U 670A
will
t
h
e
n
go
L
O
a nd α
Β Sweep will be i n itiated .
Alternate
Dis p lay Switc h i n g L ogic
T h eo r y of O p e r atio n -2235 Service
Wh e n t he H O R IZO N TA
L M
OD
E switc h is i n t h e A L T po-
sition, p in 5 of U 665
B
is
ΗΙ . T he
o
u t p uts of U 670 B an d t he Β
Gate signal
from
t
h
e out
pu t of U 665D toget h er wit h t h e IN
T EN SITY controls determine
t h
e
inte n sity of t h eΑ and Β
Swee ps .
T he Alternate Dis p lay Switc h ing L ogic circ u itry controls
bot h t he
H orizontal Am p lifie r swee p switc h i ng and t h eΒΖ -
Axis L ogic
switc h ing .
Wh en t h e Α Swee p is displayed, t he Q output of U
670 B
is HI and t he U out p u t is L O . T h ese o u t pu t levels
will
bias
on
H OR IZO
N TA L M
OD
E switc h S648 selects t he in pu t logic

Q680 and bias off 0685 . T he emitter voltage of Q680
will
levels
t h
at are
applied to t he circ u itry . In t he Α H orizontal

reverse bias C R 817 to prevent Ζ -Axis d r ive c u rre n t
fr
om
M ode, t h e S input of U
670 B
is
L O and t he R input is HI . T h is

flowing t h roug h t he diode . W it h Q685 off, additional Ζ
-Axis
h olds U 670 B set and allows only
t he Α Swee p to be p assed
drive curre n t to intensify t he Α Swee p will b e s upp lied
w h en-
to t
h
e
H orizontal Am p lifier .
In
t he Β H orizo n tal mode, t h e set

ever C R 685 is biase d off . Si nce in p ut pin 5 of U 665
B
is HI,
in p
ut of U
670 B is HI and t h e reset i np ut is L O to h ol d

t h e gate out pu t and t h erefore t he conduction
state of
U 670
B reset an d allow only t he Β Sweep to reac h t he H ori-

CR 685 is determined by U 665 B p in 4 . Wh enever
t h
e
Β
zon tal Am p lifier .

Swee p is running, t he o u t p ut of U 665D will b e
L
O .
T h
is
will
cause t he output of U 665 B to also be L O and C
R
685
will be
b iased off . If t he Β Swee p is not ru
nn ing, t h
eo
u t pu t of
W
it
h
S648
set to A L T, and for all setti n gs of t he VER TI-

U 665 B will be HI and CR 685 will b e b iased
on . T h is will b ias
CA
L M
OD
E switc hes exce p t BOTH-ALT, t h eV ~lt signal αρ -

off CR 816 an d t h e Α Sweep will not b e
intensifie d .
p
lied to U
660 E and t he S an d R i np uts of U 670 B are all HI .
T he L O output of U 660 E causes t he o u tp u t of U 680 B to be
HI, and
w henever t he Alt Sync signal a pp lie d to p i n 1 goes

If t he outputs of U 670 B are set to
d isplay t he Β Swee p
L O, t
h
e gate o
u tp u t will ch ange from L O to HI and cloc k
(Q L O and Q HI), 0680
will b e b iased off and Q685 will be
U
670 B . T he outp uts of U 670 B will t h erefore toggle wit h

b iased on .
T h
e
emitter voltage of Q685 will reverse b ias
eac h Alt Sy nc signal transitio n to alte r nately ena b le t h e Α

C R 816 to p revent
Ζ -Axis drive cu r rent from flowi ng t hr oug h
and Β Sweeps to reac h t h e H orizontal Am p lifier . Wh e n eve r

t he d iode .
W
it
h 0680 off, t h e Β Swee p will be displaye d if
t h eΒ Swee p is selected for t he H orizo n tal Amplifier, t h e 0

C R 680 is reverse biased .
Wh enever t he Β Sweep is r u nning,
output of U
670 B will be HI
.
T h is HI is app lied to U 665C p in

t he outp ut of U 665D is
L O . Diod e C R 680 will t hen b e re-
9, and
since p in 10 is also ΗΙ , t he Se p signal from U 665C

ve
r
se biase d
and Ζ -Axis drive current will flow t h roug h
will
be
L O to enable t h e Α / Β Sweep Se p aration circ u itry .

C
R 817 . If t h
e
Β Swee p is n ot r un ning, t he outpu t of U 665D
is HI, forward
biasing
C
R 680 a n d t h erefore reverse biasi ng
C R 817 . No Ζ -Axis d rive cu
r rent
can
t hen flow t h roug h
Wh e
n
t
h
e C
H
1-BOTH-CH
2 VER TICA L M OD E switc h is

C R 817 .
set to BOTH,
t h
e
ADD-A L T-C H O P switc h becomes func-
tio n al
.
In t
h
e
AL T VER TICA L M OD Ep ositio n , t h eV ~lt sig n al
is LO, t
h
e
H
alt
signal
is HI, and
t he C H 1 Selecte d sig n al is α
TT L
s q uare wave
t h
at
switc hes states at t he en d of t he Α

H O R IZO
N TA L
Swee p . I np ut p i n 4 of U 680 B will be HI a nd t he gate o u t pu t
will b e t he inverse of t he C H 1 Selected sig n al . T h is out p ut

T h eH orizontal Am p lifier ci
r cuit,
s
h own
on
Diagram 6,
signal is N A N De d wit h t he Alt Sy nc signal by U 680A to

provides t he output signals t h at d
rive
t
h
e
h orizontal crt d e-
cloc k U 670 B . Wh enever t he Alt Sync sig n al goes L O at t he

flectio n p lates . Signals a pp lie d to t
h
e
H orizontal P ream p lifie r
e nd of α sweep and t h e C h 1 Selecte d sig n al switc hes from

can come from eit h er t h eΑ or t he
Β M iller
Swee p Ge
n erator
L O to
HI,
U 670 B will be cloc ke d . Since only p ositive transi-

(fo r swee p deflectio
n )
or
f r
om
t h
e
ΧΥ Am p lifier (when Χ - Υ
tions on t he cloc k i np ut will cause t he flip-flo p to ch an ge

display mode is selected) . Swee p
switc h i n g is under control

Tektronix 2235 Specifications

General

Brand	Tektronix
Model	2235
Category	Test Equipment
Language	English