Nordson 303 779B, Customer Product Manual

Page: 106 / 176

Troubleshooting
B 5-16
E
1998 Nordson Corporation
All rights reserved
303 779B
Issued 11/98
Manual 12-44
Problem Possible Cause Corrective Action
22. Zone turns ON, but
does not control or
trips breakers or
Zone failure occurs
and the zone is not
on (setpoints=0)
Incorrect voltage Verify 12 Vac is at 2 position IDC connector
on the SCR feedback card.
S
If 12 Vac is not measured:
Go to 3
∅
transformer. Refer to
3
∅
Transformer Check in this section.
Check ribbon cabling from SCR
controller board to feedback card.
S
If 12 Vac is measured:
The cable is OK. The feedback card or
SCR controller board may be defective.
Refer to
Zone Voltage Test in this
section.
Defective feedback card Replace the feedback card.
NOTE: When replacing a feedback card,
the current donut has a white dot on one
side. The wire must pass through with the
dot facing the breaker.
Defective SCR controller board Replace the SCR controller board.
Defective ribbon cable Replace the ribbon cable.
23. Zone turns ON, but
does not control
the temperature
Dip switches set incorrectly NOTE: Turn power off. Observe local
Lock Out Tag Out procedures.
Check dip switch configuration on CPU
and I/O boards. Refer to the
Specifications
section for dip switch settings.
Defective feedback card Replace the feedback card.
NOTE: When replacing a feedback card,
the current donut has a white dot on one
side. The wire must pass through with the
dot facing the breaker. See Figure B 5-1.
24. Actual temperature
display is
unreasonable
Thermocouple may not be correctly
positioned in the process cavity Seat the thermocouple board correctly in
its holder and secure with set screw.
Defective thermocouple board Replace the thermocouple board
25. Temperature drops
while wattage
increase (or the
opposite occurs)
The thermocouple wires are installed
backwards on thermocouple board Reverse the wires on the thermocouple
board.
2. Troubleshooting Table
(contd.)