Tektronix 576 - Page 45

Circuit Description-Ty p e 576
two alternate p ositions, labele d 75 an d 350 in F ig . 3-3 Α .
C hanging the connection of this wire allows +12 .5 volts to
be a pp lied to Κ323 t h roug h Β 360 regardless of t h e state of
H ig h V oltage I n terloc k switc h S
W
360 .
T
he DA N G ER O U S
V OL TAG E lig h t is turned on in t he 75, 350 and 1500
p ositions of t he MAX PEAK VO L TS switch even if t he
i n
terloc
k h
as been by p asse d . If
Β
360 were to
burn
out, t
h
e
collector
supp ly
woul
d
be automatically d
isable d .
T he interloc k system may also be mo d ifie d for use in all
p ositions of t h e MAX
PEAK
VO LTS switch . T h is mo d ifica-
tion may be p erforme d by removing t he groundfrom t he
15 V position of wafer 1 R and connecting t h is p osition to
t he 75 V p osition of 1 R . T h is wiring c h ange ma k es it neces-
sary to close S W 360 (using t he p rotective box) in or d er to
activate Κ323 and enable t h e collector su pp ly voltage .
T h ese alternate connections are located on wafer 1 F and
1 R of t h e MAX PEAK VOLTS switch , i n side t he guar d box
on t h e left of t he instrument . F ig . 3-3Β sh ows α p icture of
3-4
t his wafer and labels the alternate connections . The bypass
mo d ification is p erformedby sold ering α j um per wire be-
twee n terminals 11`19 and 11`20 (75 by p ass) or between
termi n als 11`19 an d 1F2 (75 and 350 by p ass) . To mo d ify
t h e i n terloc k system for use on all maximum pea k voltage
ranges, unsolder t he existing j um p er wire con nected be-
tween terminals 1R17 and 1R1, from 1R17 an d resol d er it
to t he buss wire connecte d to terminal 1 R 3 . In unsol d ering
t h e j u m p er wire from terminal 1R17, be sure t h e w h ite wire
remains sol dered to t h e terminal .
W A RN I NG
T h
e
Ty p e 576 is co n si d ere d safe as s h i pp ed . Any
mo
d
ification of t he i n terloc k system in order to over-
ride its purp
ose of p rotecting operators from danger-
ous voltages,
will ma k e operatio n of t h e i n strument
pote n tially h
azar
d
o
u
s .
O
p erators of t h e instrument
s hould always be aware of t he fact t h at w hen
t
h e re d
lig h t is on d a
n
gerous voltages may a pp ear at
t h
e Col-
lector terminals .
0-40
1 R5
0-411
1R7 Ι
L 4
E
J
J 300
+12 .5 V
-12 .5V
Τ 300 -12 .5 V
S W 360
(H .V . Interloc k
)
Β 360
DANGEROUS
V OLTAGE
Κ 323
CO LLE CTO R S UPPL
Y
VO L TAG E DISA BLE
F
ig . 3-3 . ( Α ) Sim pli fied sc h ematic o f interlock circuit, ( Β
)
p ict u re
o f wafer IF and I R o f
MAX
PEAK VO LT S switc h located ins i de
guard
box .
11`19 Ι
1
1 F 2
1 F20 Ι
~-
(75 an
d
350 B ypass)
(75 B ypass)
f
15
0-10 0 75
0
350
0
ι
0 1500