Tektronix 2213 - Page 143

P O WER S UPPL Y ISOLATIO N PR OC
E D URE
E ach r egulated s
u pp ly h as n ume r ous feed p oi n ts to external loa d s t
hr
o
u gh
o
u t t he inst ru me n t . T h e p ower
d istribution
d iag r am is u sed in co nj unction wit
h
t
h
e sc
h e m atic d iag r a m s to dete r mine t hose loa ds t h at can b e
isolated b y
removing se r vice ju m p ers a nd t h ose t
h
at ca
nn
ot .
T he p
owe r dist r i bu tio n d iagram is d ivided
i n
to
ci r cu it boa r ds . E ac h p ower su pp ly feed to α circ u it boa
rd
is
i n d icated
by t he schematic d iag r a m nu mbe
r
on
w h ic h t h e voltage a ppea r s . T h e schematic d iag r am g r i d location
of α
se
r vice ju m p er or co mp o nent is give n a dj acent
to t he com pon e n t n u m be r on t h e p owe r d ist r i bu tio n diagram
.
If α power su pply comes up afte
r lifting one of t he mai n j umpe r s fr om t he p owe r s upp ly to isolate t h at su pp
ly,
it
is ve
r y pr
obable
t h at α s h o r t exists in t h e ci r cu it r y on t
h
at sup
ply li n
e .
By lifti n g ju m pe r s fa r t he r d own t h e li n e, t
h
e
ci r cu it
in w h ic h α s h o rt exists m ay b e located .
Ty p ical resistance
values to g r o u nd fr om t he
r
egu lated su pp lies outpu
t as measu r e d at t he sup p ly test poi n ts
a r e :
R esistance
values significantly lowe
r
may
i nd icates sho r te d com p one n ts in t he loa d . V al ues will va
r y between
i n st rum e
n
ts .
Always
set t h e P O WER switc
h
to O
FF b efo r e sol de r i ng or un sol de r ing service j um p ers o r ot
h
e
r compo n en ts
an
d befo r e atte mp ti ng to
measu r e components r esistance val ues .
-8 .6 V 114 0 at ΤΡ 500
+8 .6 V 95 Ω at W 975
+5 V 330
Ω
at
W
985
+30 V 905 Ω at W 965
+100 V 12 .5
k Ω
at
W
966