ALPHA ed-Lock Suddenly I'm worried about the mysterious warning sound

"Inspection for sudden warning sound from several days ago"

When I press the lock numeric keypad, a warning beep sounds after the deadlock action. "beep beep, beep beep, beep beep" beep three times in a row.

Sometimes it does not respond when pressing the unlock numeric keypad. Since it is an old apartment, the movement of the LA lock case was a little stiff, so I thought it was an error sound such as insufficient motor torque.

I unlocked the battery replacement cover by bypass, replaced it with a lithium battery for operation check, and operated it, but the warning sound still sounded and there was no improvement.

So I removed the control unit body to isolate the problem. In that state, I performed the locking operation, but it still did not improve.

Defective control board due to sensor malfunction. It seems that It's probably a photo sensor that detects the rotational position.

In this case, the unit will need to be replaced. I was going to dismantle the unit itself as well, but since I had the next incident in mind, let's save it for another time.

Since the unit replacement is due to deterioration, it was arranged via the management company.

The numeric keypad had deteriorated considerably, so it seems that the white corrosion has progressed to the sensor circuit on the board.