Maytag MFR Series Service Manual page 6

Testing transformer MFR18 & 25 ...................................................................................... 7-17
Testing temperature sensor .............................................................................................. 7-18
Quick Test: ................................................................................................................. 7-18
DiaGnOSTiCS & TROuBleSHOOTinG ................................................................................ 8-1
Proper grounding and polarization of 120 volt wall outlets for MFR18 & 25 ..................... 8-1
MFR30 - 80 power supply ................................................................................................. 8-1
Troubleshooting Mitsubishi inverters ................................................................................ 8-2
Troubleshooting AKO inverters ......................................................................................... 8-5
Remove inverter cooling fan ............................................................................................. 8-6
Inverter "do not's" .............................................................................................................. 8-7
Troubleshooting at control board ...................................................................................... 8-8
MC4 Control Boards.................................................................................................... 8-8
MC5 Control Boards.................................................................................................... 8-9
Diagnosing The Control Board .................................................................................... 8-10
Troubleshooting Display Problems ............................................................................. 8-11
R1 - Harness Plug ....................................................................................................... 8-12
DL1 - Door Lock Connector ........................................................................................ 8-13
T1 - Temperature Sensor ............................................................................................ 8-13
L1 - Debit Card Reader ............................................................................................... 8-13
RS485 - Serial COM1 ................................................................................................. 8-13
TTL Y1 - Serial COM2 ................................................................................................. 8-13
D1 - MC4 12VDC Tap ................................................................................................ 8-13
MC5 24VDC Tap ................................................................................................. 8-13
A1 - Coin Acceptor ...................................................................................................... 8-13
K1 - PD Key Pad Connector ....................................................................................... 8-14
F1 - Frequency Inverter............................................................................................... 8-14
GA - Display Connector............................................................................................... 8-14
P1 - Input Power ......................................................................................................... 8-14
Q1 - MC5 PN - Chemical Supply ................................................................................ 8-14
M1 - Output Voltage Test Point ................................................................................... 8-14
MC4 PD Upgrade To MC5 Board ................................................................................ 8-14
Troubleshooting motor ...................................................................................................... 8-15
Troubleshooting belt tension - MFR40 - 50 ....................................................................... 8-16
Troubleshooting drain valves ............................................................................................ 8-18
Troubleshooting door lock ................................................................................................. 8-20
Remove door locked switch .............................................................................................. 8-21
Remove latch bar .............................................................................................................. 8-22
Remove bimetal ................................................................................................................ 8-23
Remove blocking bar ........................................................................................................ 8-24
Remove door closed switch .............................................................................................. 8-24
Remove door lock solenoid .............................................................................................. 8-25
Remove door unlock solenoid .......................................................................................... 8-25
Verification of door gasket pressure ................................................................................. 8-26
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