Board Exchange Procedures - Toshiba MMW-AP0481CHQ-E Service Manual

9. P.C. BOARD EXCHANGE PROCEDURES
Replacement of control P.C. boards
Part code Model type P.C. board type
431-6V-673 MMW-AP0481CHQ series MCC-1643
Points to note when replacing control P.C. board assembly
The electrically erasable programmable read-only memory (hereinafter EEPROM, IC503) mounted on a P.C.
board holds important setting data, including the type and capacity codes intrinsic to the model (set at the
factory), as well as the line / indoor (including hot water module) / group addresses, and the like (during
installation, either automatically or manually). Proceed with the replacement of a P.C. board assembly in
accordance with the procedure described below.
After completion of the work, check the settings again, including the hot water module No. and group header /
follower designation, and confirm the integrity of the refrigerating cycle by conducting a test operation, etc.
<Replacement procedure>
Method 1
If it is possible to turn on the hot water module and read the setting data from the P.C. board to be replaced via
a wired remote controller -
Reading EEPROM data: Procedure 1
Replacing P.C. board and turning on power: Procedure 2
Writing EEPROM data in new EEPROM: Procedure 3
Resetting power supply (applicable to all hot water module units connected to remote controller in case of
group operation)
Method 2
If it is not possible to read the setting data due to the failure of the EEPROM itself -
Replacing P.C. board and turning on power: Procedure 2
Writing EEPROM data on basis of information supplied by customer: Procedure 3
Resetting power supply (applicable to all hot water module units connected to remote controller in case of group
operation)
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