Tektronix 454A - Page 157

NOTE

8 . I f t h e C
R T d i spl ay excee d s t h e l i mi t s of t h e c h ec k
st e p , a dj ust C178, R 175, C190 an d R 190 as necessar y t o
T he 4%
speci f i cat i on on aber r at i ons i s appl i cabl e at

ob t ai n t h e best r i set i me an d f l at t o p .
t he t emper at ur e of +25 ° C, ±5 ° C .
9 . Di sco nn ect t h e s p
eci al BN C ca b l e f r om t h e i nst r u-
ment .
f . AD JU
ST- I f t h e C R T di s p l ay exceeds t h e l i mi t s of
t h e C HE C K - st e p , use t h e f ol l owi ng ad j ust ment pr oce du r e .
See F i g . 5- 12 f or l ocat i on of a d j ust ment s .
1 . R emove
t h e si gnal f r om t h e C H 2 i n p ut connect or .
2 . R emove

t h e G R 5O E2 i n- l i ne t er mi nat i o n an d
r e p l ace i t wi t hzyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ± G R t o BN C a d a p t er . At t ac h t h e speci al
BN C ca b l e s h own i n p ar t 2 of st e p
21g
t o
t h e G R t o
BN C a d a p t er
.
3 . R emove Q144 f r o m i t s soc k et .
4 . Appl y t h e si gnal f r om t
h
e f ast - r i se pul se ge
n er at or
t o t h e col l ect or
l ea d of Q144 by i nser t i n g t h e l oose l ea d
of
t h e 150 © r esi st or i nt o t h e col l ect or hol e of t h e Q144
soc k et .
5 . A d j ust t h e f ast - r i se p ul se gener at or out p u t si gnal
am p l i t u d e t o o b t ai n ±
4-
d i vi si on di s p l ay .
6 . U se R 334
( V er t i cal Cent er i ng adj ust ment
i n t h e
V er t i cal Out
p ut Am p l i f i er ) as ± p
osi t i oni ng cont r ol t o
cent er
t h e di s p l ay ver t i cal l y
.
7 . C h ec k t h e C R T d i spl ay
f or opt i mum r i set i me a n d
f l at t o p . Aber r at i ons
s h o u l d be 3° / ¿ or l ess . U se t h
e
nar r ow p ul se
ampl i t u d e as an i n d i cat or of am p
l i f i er
b a nd wi dt
h . T h e n ar r ow pul se am p l i t u d e s
h
oul
d be 52° / ¿
or m or e of t h e l onger p ul se am p l i t u d e .
10 . R ei nst al l
Q144 i n i t s soc k et .
A d j u st ment - 454A/ R 454A
11
. R emove t h e s p eci al BN C ca b l e f r om t h e si gnal
sour ce an d r epl ace i t wi t h ± GR 50 © i n - l i ne t er mi na-
t i on .
12
. R ea dj ust V er t i cal Cent er i ng ad j ust me n t R 334 as
gi ven i n A dj u st ment P r ocedur e St ep 14 .
13 . Appl y t h e si gnal f r om t h e f ast - r i se
pul se gener a-
t or t o t h e C
H 2 i np ut connect or and a dj ust f or 4- d i vi si on
d i s p l ay at 10 m V / d i v .
14 . Ad j u st R 116 an d C116 f or mi ni m u m a b er r at i ons .
15 . A d j ust
R 149 H
an
d C149 H f or best p ul se- t o p f l at -
ness .
16 . Ad j u st R 144 an d C145 f or best p ul se f r ont
cor n er .
17
. Set t h e C H 2 V O L TS/ DI V swi t c h t o 20 m V
an
d
r ea dj ust t h e f ast - r i se p ul se gener at or f or ± 4- d i vi si o n
d i s p l ay .
18 . AD JU ST- C125 E f or b est f r ont cor n er .
19 . Set t h e C H 2 V O L TS/ DI V swi t c h
t o 50
m V
an
d
r ea d j ust t h e f ast - r i se pu l se gener at or f or ± 4- d i vi si on
di s p l ay .
20 . AD JU ST- C116, C122 an d R 133 f or b est f r ont
cor ner an d p ul se- t o p f l at ness .
• Ÿ¤•
² 116, C116, R 133 and C122 have t he most ef f ect i n
t he 50 mV posi t i on of t he VOL TSI DI V swi t ch .
21 .

I f n
ecessar y, t h e val ue of R 129 can b e sel ect ed t o
ac
h i eve mi ni m u m a b er r at i ons .
22 . Set t h e C H 2 VO L TS/ DI V swi t c
h
t o 5
mV
an
d
r ea dj u st t h e f ast - r i se p
u l se ge n er at or f or ± 4- di vi si on
d i s p l ay . A d d at t e nu at i on as necessar y t o o b t ai n t h e
desi r e d di spl ay am p l i t ude .
23 . AD JU ST- R 149G an d C149G f or b est f r ont
cor ner .
24 . Set t h e C H 2 V O L TS/ DI V swi t c h t o 2 m V and
r ea dj u st t h e f ast - r i se p ul se gener at or f or ± 4- di vi si o n
di s p l ay .
25
.
ADJUST- 13149A
f or b est cor n er .
26 .
R e p eat st eps 14 t h
r o
u g h
25
unt i l p
r o p
er
co
m -
p ensat i on i s obt ai ne d i n al l p osi t i ons of t h e V O L TS/ DI V
F i g .
5- 12 . L ocat i o n of C H 2 compe
n sat i o n a dj u st m ent s .

sw
i
t ch .
5- 43