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HP 8110 Α Service Gui de
Ca
u
tion
RIS K O F EXPL OS IO N!
D
O NOT allow Lit hium batter ies to
b
ecom e short-c ircui ted
D
O NOT
u
se excess ive heat wh e n unsoldering/sol der ing Li t hium
b atteri es .
D
O d i s p ose of b atteries in an appro v ed
m
anner.
4- 1 6 Troubles
h
ooti
n
g
RP G Uni t
Thi s uni t sends an interrupt to t h e Microprocessor, and
α
d
i rect i o n al signal. These sig nal s are buffered by U43C
an d
U
43 D. Ch eck that whe n
t
he kno b is rotated signals
are
p
resen t at the input, pin 9 and at the output, pin 8
o f U43C an d at the input, pin 12 and at the output, pin
11 of
U
43 D
Reset
At switch-on
U
13 pin 16 goes high.
I
t the n goes
l
ow
a
fter app roximately 100 ms, and remain s
l
o w unt il α
s ubsequent reset .
If th e Mi cro p rocessor Board p asses all the abo ve c hecks and still does
n
ot fun ct io n,
i
ts rep air is outsi de the sco pe o f this
T
ro ubleshoot ing
gui de, and i t
i
s reco mme nded t hat the
P
C Board
b
e ret u rned to α
H ewl ett-P ackard Service Center .
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