HP 5383A

M o
d el 5383 Α
Ope r atio n
Pr oblem Ill . T he f r equ ency co un
ter is n ot
co
un ti n g t h e in pu t sig n al .
C HE C K :
α .

Is t h
e
r ear pan el ΙΝΤ/ ΕΧΤ switc h i n t he ΙΝΤ positio n ? (T h is switc h exists i n t h e sta nd a rd
coun te r only .)
b .

Does t h is pr oblem occ ur only
w h
e n t
h
e
f
r o
n
t p a n el I NPU
T switc h is i n t he
50
Ω Χ 1 o r 1
ΜΩ
Χ 1 p ositio n ? T h is
i nd
icates t h at t he
i
n te rn al f u se, A1
F
1, is
blow n . R emove i n
st
r
ume
n
t
cove
r
s to gain
access
to
t h is f u se (refe r to P a r ag r a ph 5-17, n ote W A RN I NG) . R ep lace f u se
wit h s p are p r ovi ded on t he M ain Boa rd Assembly . Or de r a n ot h e r f u se (HP P art Nu mbe r
2110-0436) .
ΝΟΤΕ
REMEMBER TO KEEP ΤΗΕ I NPU T SIG N A L LEVEL BEL O W 3 .5 V
( RM S) O R +24 D BM WHEN ΤΗΕ I NPU T S W ITC H IS IN ΤΗΕ 50 Ω
Χ 1!
ι .

Does t h is pr oblem occur οηΙ ;- w
h
en t h e
I
NPU
T switc h is i n t he 1 ΜΩ Χ 1 o r Χ 10
p ositio n s a nd t h e i npu t f r e qu ency goes
h ig h
e
r t h a n 100 kH z? R emove t he cove r s
( r efe r to P a r ag r aph 5-17, note t
h
e W A RN
I
NG) .
Set t h e boa rd -mo u nte d F I L T ER
switc h to t h e left (i .e ., away
f r
om
t he ">") .
3-12 . F inally, t h is q uic k and co
n
ve
n
ie
n
t loop-around
c heck is p r ovi ded to ve r ify n o r mal
ope r ation of t he
i
n str u
m
e
n t :
α .

Set
t h
e
rea r pa n el ΙΝΤ /ΕΧΤ switc h (exists on t he sta nd a rd coun te r only) to the INT
p ositio n .
b .

Set t he f r o n t pan el I NPU T switc
h
to t
h
e 50 Ω Χ 1 p osition
.
ε .

Co nn ect α coaxial ca b
le
b
etween t h e r ea r p a n el OSCI LL ATO R j ac k a nd t h e f r ont p a n el
I NPU T j ac k .
d . 10 MHz d is p lay (±1 least-sig n ificant d igit) i nd icates t hat t h e coun te r is ope
r
ati ng
- - no r mally .
e . Fo r loop-around chec k of t he 1 ΜΩ Χ 1, o r Χ10 I N
P
UT p at h s, u se α 500
F
ee
d t hru
con n ecto r (see Table 5-1,
test
2 items e,
f, g .) .
3-13 .

If, afte r t h ese ope
r
ato
r c heck s a r e pe r fo r me d , t h e coun te r d oes n ot ope r ate no r mally,
r efe
r
to the Troubleshooting C
h arts : F ig ur e 5-1 a nd 5-2 in Sectio n V fo r fa u lt analysis p r oce dur es .