135
Troubleshooting
Error code 54, TACHO, NO SET SIGNAL
DLCU counts the tacho pulses from the motor in order to guarantee that
the drum is stationary when the door is opened. To ensure that the signal
from the tacho generator is working correctly, DLCU compares the tacho
signal to a digital bit value from the CPU processor, which is due to the
CPU having activated the motor. The tacho signal should always cor-
respond to the digital bit value and if the tacho signal is present without
the digital bit value, an error message will be generated to CPU.
The error message is filtered in such a way that the drum must rotate and
stop twice without the ”should rotate” signal being present before an error
message is sent to CPU.
The DLCU processor will reset itself when the error has disappeared.
CPU reads the error message when the program finishes and generates an
error code, the error message is ignored between these two occasions.
Reason:
The error can be caused by cross talk in circuits in the CPU, or caused by
damaged components in the CPU.
Action:
If the error returns after a reset, change the CPU.
