E-2
TROUBLESHOOTING
E-2
CAUTION: Sometimes machine failures appear to be
due to PC board failures. These problems can some-
times be traced to poor electrical connections. To
avoid problems when troubleshooting and replacing
PC boards, please use the following procedure:
1. Determine to the best of your technical ability that
the PC board is the most likely component causing
the failure symptom.
2. Check for loose connections at the PC board to
assure that the PC board is properly connected.
3. If the problem persists, replace the suspect PC
board using standard practices to avoid static elec-
trical damage and electrical shock. Read the warn-
ing inside the static resistant bag and perform the
following procedures:
P.C. Board can be damaged by static electricity.
a. Remove your body
’
s static
charge before opening the
static-shielding bag. Wear an
anti-static wrist strap. For
safety, use a 1 Meg ohm
resistive cord connected to a
grounded part of the equip-
ment frame.
b. If you don
’
t have a wrist strap,
touch an unpainted, ground-
ed, part of the equipment
frame. Keep touching the
frame to prevent static build-
up. Be sure not to touch any
electrically live parts at the
same time.
c. Tools which come in contact with the P.C. Board
must be either conductive, anti-static or static-dis-
sipative.
ELECTRIC SHOCK can
kill.
Have an electrician install and
service this equipment. Turn the
input power OFF at the fuse box
before working on equipment. Do
not touch electrically hot parts.
d. Remove the P.C. Board from the static-shielding
bag and place it directly into the equipment. Don
’
t
set the P.C. Board on or near paper, plastic or
cloth which could have a static charge. If the P.C.
Board can
’
t be installed immediately, put it back in
the static-shielding bag.
e. If the P.C. Board uses protective shorting jumpers,
don
’
t remove them until installation is complete.
f. If you return a P.C. Board for credit, it must be in
the static-shielding bag. This will prevent further
damage and allow proper failure analysis.
4. Test the machine to determine if the failure symp-
tom has been corrected by the replacement PC
board.
NOTE: It is desirable to have a spare (known good)
PC board available for PC board trou-
bleshooting.
NOTE: Allow the machine to heat up so that all elec-
trical components can reach their operating
temperature.
5. Remove the replacement PC board and substitute
it with the original PC board to recreate the original
problem.
a. If the original problem does not reappear by sub-
stituting the original board,then the PC board was
not the problem. Continue to look for bad connec-
tions in the control wiring harness, junction
blocks, and terminal strips.
b. If the original problem is recreated by the substi-
tution of the original board, then the PC board
was the problem. Reinstall the replacement PC
board and test the machine.
6. Always indicate that this procedure was followed
when warranty reports are to be submitted.
NOTE: Following this procedure and writing on the
warranty report,
“
INSTAllED AND SWITCHED
PC BOARDS TO VERIFY PROBLEM,
”
will
help avoid denial of legitimate PC board war-
ranty claims.
PC BOARD TROUBLESHOOTING PROCEDURES
ATTENTION
Static-Sensitive
Devices
Handle only at
Static-Safe
Workstations
Reusable
Container
Do Not Destroy
WARNING
DC-600
