The
second
resistor
0f.200
X',
making
up
the
Ox
10,000^circuit
can
be
checked
on
points
i5
and
18.
The
tesr
meter
musr
oe"sei
on1r""Oi'iooo
rrrg;;;;i;."'p;;i"It"i'r,e
sioe
0f the
mains
prug
sh.rtcircxited_and
the
n.;4i.";.;.ud
at the
end
0f
the
scare.
Then
shortcircuit
points
15
and
14.
The
coniinuiti-
or
i:"r.,.
-Lriitoi
-i. -iroi*tru""lv""itil
neeore
going
over the
end
of the
scale.
PARAGRAPH
5)
A) Alteration
0f
the
resistance
rrarues.ot
the-c,mp,nents
0f
the
'hms
and amps
circuits;
this
fault
can
be
caused
enther
bv
the ,.risioiilorrific
;;;i;i
t;;.ril;rir*ii",ir"1,o#'ior*,ng
part
of
the
.ampere
circuit
cbmplementary
to ii.
''
"-"
'
l0
carry
out
this
test
it is
necessary
io
havc
a
reriabre
Test
Meter
with
a
good
internar
baitery.
Bear
in
mind
that
the
overioais
[..0,-ii",i,i*t
cases,
to
raise
the
varue
of
the
resistors.
Set
the
refcrence
Test
Meter
with
-the
red
probe
in
the
Cl
socket
and
the
black
drobe in
the
10
V DC
sccket.
tnsert
the
tree
eno
"oi
t"rlo",.i'"prre
"i;
i;."sb
r:A"
#:k"Jt
Pa'nri
tire
free,
end.of
the
black
plug
in
the
(=i
so.tei.
!.v
iwv
I
il
the
v0ltage
of
the
batterv
i.n
.the
reference
test
Meter
is
exacfly
3
vorts,
the
test
Meier
being,
teste_d
wil
indicate
15
divisions
f.,
ilii
iiib'sili'
Set
the
reference
Test
Meier
0n
Q
rlb00.-
-rn#i
in"e''
lra.l
probe
in
the
(__
)
socket
and
the
reC
probe
in
the
500
sA
socket.
fle
reaaing
wifi''[e'OS
uti.
set
the
reference
Test
Mdter
on_ox
100,
rnieii'flr.
oia.ri
pr'be
in
the
(:)
socket
and
the
l:9 ll*:",:I..1If
'-o_,_k'i.^^Tn-e
reaaihg
*iii
tu
,pp?or.
sso
un.
1".,""T.*n:rl5,."'.^:lq":,$,^lljlA.gryi.l;
,60'r.
"6.r?ing"i,*frind
fo,
the
50
mA
range
i?""J, :1"'"i"'t1fl",'"
T^".tJl't"'i,'iL:lq-g
i:9 li'-q",;il;
ih;
'r;
;'i"
r,il't#'trfr'
i.l'i
'ffi
IJ,..":rll.^11..-_litl,J,.g
o.s mA,
for
the
ririf
ina
6i,..;n
l;;
iil.'';;.iriA
ll,
tL'"..::1'1u,'
IIi:'j,'I'^id:l:ntv
trom
thoie
;;;ii;r;;
,''iu
ii.li"airr.'ences
are
c,nrirmed
py t!9
end
of
scate
0hms
checiis,
reptace-ttre
itruni"iuiirto,
,naei
ieit.
lf,
after
the
check,
the
current
valuei
reaA coninr.'*iii +r."." in/ina+^d
conform
with
those
indicated
the
end
of
scale,
l:ll:1,:j,f: _'L
tL.*:.:ll:H_ql,I";j:i9
!i,;i"i,"."n,"iii.'i'u'u"t";'i;'"th,;,''Ji,l,jli,
,i,i..1,'.1
relative
to
the ohms
circu"it
whicti
,r.i
6.
ii,uiiiiri.a.
46
t,^IIAGRAPH
6)
/\l
tlult in
the
Ampers
circuit
in
0.C.:
see
paragraph
2E),3A)
and 5)"
r,nilAGIlAPtl
7)
r\)
trntts in the
Ampere
circuit
in A.c.: if
the test
meier
does
not
work
in the
A.c.
Ampere
,
,,
1i,i,
1f,li
miy
ld causea
by the
interruption
or
alteration
of the
resistors
in the
shunt
r
lr,rrrr
which composes
the D.C.
Ampere circuit.
tr
*,,rri,
it
ii idvisable
to check
the circuit
as
in the
instructions
in
paragralh
6)'
.lf
the
tL t,rlic is etiiclent,
irre
fault
must be
in the
rectifying
section
made
up of.a_diode,
the
.,,.,,,,'iixed
calibrati6n
rheostat
and two
resistors.
Tire-efficiency
of
the rectifying
section
,.rr
oilsily be measured
as
followsr
,,,t
rt,.
ieteience
Test
Meter
on
Ox1000,
insert
the end
of the
positive
prgbe
(O)..in
the
.',tt,,A
,.c., socket
and
the
negative
probe'in
the
common
AC. socket
(-)'
lf
the
diode
is
",r,ilig
pio'p.rfv,-tf.,u
n..ai.
of"the
iirsirument
being
tested
should
be approximately
0n
the
'.'rrrl
division
of
the
black scale.
rr,,u,,r,tn'ii."p.nei
and
repeat
the
test: lf
the diode
is
working
properly_
the.needle
of
the
,lr,,iLri-li,ini
iested
must always
indicate
1.5 divisions
approximatell
ptal[
19aJ9J-!o
ilrI loft of zero.-
tf the
roonr
temperature
is
high,
ihis reading
may reach
2 10
2.5 drvrsl0ns.
Lr
f iiif,.i
positive
or
negatlve
readings
are
givin,.
this
means
that
the
di0de
is conducting
* rtr
'a
rei:luied
rectifyirig
capacity.
-tf
the-readings
are
nil
or almost
nil, the
diode
is
iiir",,,ipt.a.--in both
casis,
trie oi6oe
must
be subsiltuted.
lt
is siiuated
between
points
10
.,rrl
l1
on
the diagram,
^rr',
f,uuing it1.cfr"eO
ine diode
of
the rectifying
section,
check
the
efficiency-of.the
scale
,r,,:tion
Eiotr
oi
the doubling
range secti-oni
as followsr
set
up the
Test
Meter
as
f0r
1,
r,ieviiui
cr,e.tr,
ano aepreis"the
"button.
The
reading
must
go
fro.m
22 divisions
(black
..
r,lt
-io-
ippioilniately
7'divisions
(black
scate)..
After
reversing
the
probes
press
the
r, iii,,i
rgriri."
it',.-ne6or.
wili
move from
-1.5
to approximatelv
0.5.
,lf
it does.
not,
it
,,,,.,,,,,,
ffi
ihe fault
is
in the second
di0de
or in
the circuit
associated
vrith
range
doubling'
,tr
,t
tte seciions
of
the switch
relative
to this
diode
by connecting
the red
probe
of
the
47
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