HP HP-97 User Manual

[
evs
CORVALLIS
DIVISION
97-101
PACKARD SERVICE NOTE
Page 2 of 7
(...continued)
Supersedes:
iii. Back the screw out until it makes a second contact.
iv. If it requires more than % turn to make a second contact,
the switch is good and should then be adjusted for normal use
(with plastic tool still in place). If the margin is less than
1 turn, then the switch should be replaced.
B. Set the scope to trigger on the AC line at a 1 millisecond sweep
rate, with 2v/div vertical sensitivity including the probe.
C. Put the scope probe on the head switch pick-up point. Turn the
adjusting screw clockwise until the scope trace drops from 5v to
Ov indicating the switch is closed. The switch should make and
break clean. Any erratic action will show on the scope and
indicates a dirty switch. The card reader PC board must be removed
and the contact pads cleaned carefully with a soft, rubber pencil
eraser; then pads and contacts are degreased with Freon TF or
denatured alcohol and then cleaned with a Kimwipe. After re-
assembly,
if
the
switch
makes
and
breaks
with
a
clean
signal,
back
the screw out 1/8 of a turn from the closed position.
(NOTE:
the
gold
coating
on
the
pads
should
not
be
removed
any
more
than necessary for good cleaning).
A problem may arise if a switch is bent. If it is difficult to
adjust
the
head
switch,
make
sure
it
makes
contact
at
only
one
position.
If
it
makes
multiple
contacts
when
turning
the
adjusting
screw, the switch should be replaced.
D.
Using
the
same
technique,
adjust
the
file
protect
switch
and
back
it
out
1/8
turn
also.
(continued...)
For more information, contact the Service Engineering Manager, Corvallis Division—1000 N.E. Circle Bivd., Corvallis, Oregon 97330
Telephone (503) 757-2000 ¢ TWX # 510-596-0683
Printed in U.S.A.

HP HP-97 Specifications

General

Brand	HP
Model	HP-97
Category	Calculator
Language	English