Welbilt FB081TF, Service Manual

Page: 34 / 96

34 Part Number REV00 04/08/2020
Troubleshooting Section 5
CONTROL SYSTEM
Will Not Run Diagnostics
n
Warning
High (line) voltage is present when the back and side
panels are removed.
1. Verify primary voltage is supplied at the plug.
2. Reboot by disconnecting and reconnecting the main
power supply.
3. Verify ON/OFF rocker switch functions properly and
supplies line voltage to power relay coil (T1 - T0).
4. Verify power relay contacts are closed (T2 -T4 and T6 -
T8).
5. Verify line voltage is present at the 24 VDC power
supply primary - CN1.
6. Verify 24 VDC is present at the power supply secondary
- CN2.
7. Verify in-line 4 amp fuse on 24 VDC supply is closed -
CN2 T1.
8. Verify 24 VDC is present at SRB board MTA2 (J1)
connector. Disconnect and reconnect wiring to verify
connection.
9. Duct fan, cabinet refrigeration or ice machine
operating?
- No - Replace SRB board.
- Yes - Go to next step.
10. User Interface (UI) energized?
- No - Inspect wiring, disconnect and reconnect
wiring to verify connection, replace UI.
- Yes - Go to next step.
11. Does UI progress through screens?
- No - Reload Firmware and Recipe File
See “Software” on page 17 .
- Yes - Go to next step.
12. Do any components energize during the drink making
sequence?
- No - Replace SRB board.
- Yes - Troubleshoot non functional component.
If blender is non functional proceed to Blender
Motor section.
NOTE: Both blender assemblies will require testing.
13. 24 VDC on Motor Controller Board MTA2 (J1)?
- No - Replace wire.
- Yes - Go to next step.
14. Home position switch closed on motor controller circuit
board Home SWT (J13)?
15. Door switch circuit closed on motor controller circuit
board Door SWT (J9)?
16. Door switch circuit closed and supplying 24 VDC to coil
on DPDT relay?
17. Blade DPDT relay contacts closed?
18. AC voltage present at J5, J6 of Motor Controller Board?
- No – Voltage present at J15, J16 (Left Motor) J11,
J12 (Right Motor) on the SRB?
- No – Check wiring
- Yes – Go to next step
NOTE: Motor can be tested either in the Service Menu
under the OUTPUTS Right Blade or Left Blade selection ( See
“Employee, Managers, & Service Menu Screens” on page 55 )
or within the Drink Menu selection Blend Only option ( See
“Drink Selection Screen” on page 50 ). Testing the motor
in the Service Menu will provide half voltage for 3 seconds
to the motor. Testing the motor in the Make Drink Menu
should provide full voltage to the motor for a longer period
of time determined by the recipe file.
19. When called for activation as mentioned in above note
is AC voltage present at J2, J7 of the Motor Control
Board?
- No – Replace Motor Control Board
- Yes- Go to next step
20. Blade motor running?
- No - Test capacitor - Replace blade motor.
- Yes - Go to next step.
21. Step motor operates?
- No - Replace motor.