Canon MP638 Service Manual page 43

<Ink absorber counter setting>
Set the ink absorber counter value to a new EEPROM after the logic board is replaced in servicing.
1) Before replacement of the logic board, check the ink absorber counter value in EEPROM information print.
2) After replacement of the logic board, the ink absorber counter value should be set in the service mode using the Service Tool.
In the Ink Absorber Counter section of the Service Tool, select Main from the Absorber pull-down menu.
From the Counter Value(%) pull-down menu, select the value (in 10% increments) which is the closest to the actual counter value
confirmed before replacement of the logic board, and click Set.
3) Print EEPROM information to confirm that the value is properly set to the EEPROM.
<3-3. Adjustment / Settings, (5) and (6)>
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