Board Exchange Procedures - Toshiba MMD-AP0724H2UL Service Manual

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11. P. C. BOARD EXCHANGE PROCEDURES
Indoor unit
11-1. Replacement of indoor P.C. board
Part code Model type P.C. board type
431-6V-502 MMD-AP∗∗∗H2UL series MCC-1403
Points to note when replacing indoor P.C. board assembly
The electrically erasable programmable read-only memory (hereinafter EEPROM, IC10) mounted on an indoor
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 / group addresses, high ceiling adjustment setting and the like (during
installation, either automatically or manually). Proceed with the replacement of an indoor P.C. board assembly
in accordance with the procedure described below.
After completion of the work, check the settings again, including the indoor unit 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 indoor unit 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 indoor 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 (e.g. high ceiling adjustment setting and
optional connection setting): Procedure 3
Resetting power supply (applicable to all indoor units connected to remote controller in case of group operation)
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