Tektronix 2235 User Manual

T h eory of O p
eratio n -2235 Service
of Q885 . T he emitter voltage of Q804, set by t h e Α ΙΝΤΕΝ
-

V
su p
ply is produced by C R 967, CR 970, C968, R 971, and
SITY control, is ap p lied to t he emitter of Q885 t
h
roug
h
C970
.
R 885 . Wh en t h e emitter voltage of 0804 ch anges, t
h
e cur-
re n t t h roug h Q885 ch anges p roportio
n ally
and alters
t h e

Pr
obe
A d ju st
voltage at one e nd of F OC U S control R 893 .
T he P ro be Ad j ust
circuitry, sh own
on
diagram 6, utilizes
α s q uare-wave generato
r
a
n
d
α d io de switc h i ng n etwor k to
L ow- V oltage Su pplies

p roduce α negative-goi
n g square-wave signal at PR O BE
AD JU ST
connector
J
9900 . Amplifier U 985 is con figured as
T h e low-voltage su p plies utilize center-ta p ped secon d ary

α
multivi
b rator
wit h t he time constant of R 987 and C987
windings of Τ 948 . T he +100 V su pp ly uses C R 954 and determi
n i n g t h e oscillation p erio d . Wh en t he out pu t of t he
C R 955 for rectification and C954 for filtering . Diodes C R 956

multivibrator is at t
h
e positive s upp
ly voltage, C R 988 is fo r-
and C R 957 rectify ac from ta p s on t h e 100 V wind ing, and

ward biase d .
T h
is reverse biases
C R 989 and t he PR O BE
C956 filters t he o u t p ut to p roduce +30 V dc . T h e d iode

AD JU ST connector
signal is h eld at groun dp otential by
bri d ge co n sisting of C R 960, C R 961, CR 962, and C R 963

R 990 .
Wh
en
t h
e
multivi b rato r output switc h es states and is
produces t h e
+8
.6 V and -8 .6 V su p plies . F iltering of t h e

at t
h
e negative s
upp ly voltage, CR 988 is reverse b iased .
+8
.6 V is accom p lis hed b y C960, C962, and L 960 ; filte
r i ng

Dio de CR 989 will now be forward biased and t he ci r cuit
of t he -8 .6 V is done by C961, C963, and L961 . T he +5 .2

out p ut
signal
be app
roximately -0 .5 V .

Tektronix 2235 Specifications

General

Brand	Tektronix
Model	2235
Category	Test Equipment
Language	English