Tektronix 576 - Power Supply Calibration

F ig . 5-2 .

L . V . RE G ULAT O R c ir c u it boa r d :

Location o f test
points and ad j u stments in ste p s I through 3 .
P
O
WER S UPPL Y
1 .
A
d j
ust -75 V olt Su pp ly
α . Set t
h e
Ty p
e
576
controls as s h own above .
b .
P osition
t h
e instrument
so
t h
at
t he L . V .
RE G
UL A-
TO R circuitboar d (left side of instrument) is visible
.
c .
Connect t he negative lea d of t he DC voltmeter to
gro und , p in Μ on t h e L . V . RE G UL ATO R board, (See F ig .
5-2) . Con n ect t h e p ositive lea d to t h e-75 volt su pp ly, p in Κ .
B e sure t hep ola r ity of t he DC voltmeter is set for measuring α
negative voltage .
d C HE CK F O R -DC V
oltmeter r
ea d
ing
of
-75 volts
±0 .375
volts (±0 .5%) .
e . AD JU ST- R 721, -75- V a d j ustment (see F ig . 5-2) if
t h e voltage is not correct .
ΝΟΤΕ
T h e voltage level of t h e -75-volt su pp ly affects the
calibration
of the entire i nstrumen t . Any ad j ustme n t of
R 721 will pro b a b ly re q uire the rea dju stment of all
oth er instrument ad j ustmentsaswell .
P erforma n ce C h ec k /Cali b ratio n -Ty p e 576
f .

(If d oingonly a dj ustste p s d isconnect t h e meter leads
an d go to step 4) .
2 . C h ec k Ot h er P ower Su pp ly Voltages
α M ove t h e p ositive lea d of t he DC voltmeter to t he
p ower su pp ly test p oints (ot h er t han -75 volts) liste d in
Table 5-1 . (C h ange p olarity of voltmeter for positive volt-
ages .)
b . C HE CK FOR-Meter reading oft h epower supply volt-
age wit h in t he tolerance given in t he accuracy colum n of
Table 5-1 .
c . Disconnect t h e DC voltmeter lea d s from t he Ty p e 576 .
d . Connect t h e negative lea d of t he H ig h V oltage DC
V oltmeter to ground (pin Μ of t h e L . V . RE G UL ATO
R
ci r c u it boar d ) . Be sure t he p olarity of t h e meter is set for
measuring α negative voltage .
e

Set t h emeter for meas u ring -4kV .
f . Connect t he p ositive lea d of t h e meter
to
t he
arm of
t
he
I N T EN SITY control, R 883 (see F ig . 5-3),
connecte d to t he
w h ite and p ur p le wire .
g . C HE CKF O R - M eter rea d ing of -4000volts .
h . Disconnect t h e
H ig h V oltage DC V oltmeter lea d s from
t h e Type 576 .
3 . C h
ec
kP
owerSu p ply R egulation
α . Trigger t
he
test oscillosco pe on t he internal linesignal .
b

Connect t he 1 Χ
test p robe groun d cl i p to p in Μ on t he
L . V . RE G UL ATO R
circuit boar d .
Fi g . 5-3 . L ocation of h ig h vo l tage test p oi n ts on rig h t side o f
i n st r u ment .
5-5