Mitsubishi Electric PUHY-P250YNW-A Service Handbook page 296

[9-4 Maintenance LED Display and Troubleshooting ]
3. Rewriting software
(1) Maintenance LED does not display "Pro."
(Meaning or Cause)
The system is not started in Software Rewrite Mode.
Switches SW7-9 on the control board may not be in the ON position, or the portable charger may not be charged sufficiently.
(Solution)
Make sure switches SW7-9 are ON using Section [9-3-2 Rewriting Software]as a reference.
Restart using a fully charged portable charger or a different charger.
(2) Pressing the switch for starting the storage process does not start the process, and Mainte-
nance LED continues to display "Pro."
(Meaning or Cause)
There may be a problem with the USB memory stick.
(Solution)
Check the connection of the USB memory stick.
If no problem is found, the USB memory stick may be at fault.
Check if the USB memory stick meets the specification described in Section [9-1-3 Necessary Materials](1) USB memory
stick.
If compliance is confirmed, the USB memory stick may be broken. Replace it with a new one.
(3) At the time of the system start after "END" was displayed, Maintenance LED displays "Pro."
(Meaning or Cause)
The system was started in Software Rewrite Mode.
Switches SW7-9 on the control board may not be in the OFF position.
If the switches are in the OFF position, it means the software rewrite process has failed.
(Solution)
After turning off control board switches SW7-9, turn on the system again.
If the switches are in the OFF position, it means the software rewrite process has failed.
Try rewriting the software again by following the procedure detailed in 1 (1) Starting software rewrite mode under Section [9-
3-2 Rewriting Software]. If the problem persists, rewrite the software, using a ROM writer.
(4) Maintenance LED displays "Er01."
(Meaning or Cause)
Because an error occurred in the USB memory stick before the start of software rewrite, software rewrite has not been com-
pleted.
(Solution)
Check the connection of the USB memory stick.
If no problem is found, the USB memory stick may be at fault.
Check the following four items.
Compliance of the USB memory stick to the specification of Section [9-1-3 Necessary Materials](1) USB memory stick.
The countermeasure program file "******.mot" for the intended model is used.
The countermeasure program is not for a different model or version.
The countermeasure program file "******.mot" is stored in the root folder. It is not stored in another folder.
Make sure that the program file "******.mot" is stored in the root folder of the USB memory and not in any folder created on
the USB memory stick.
When there is no problem in the above, the USB memory stick may be broken. Replace it with a new one. After data storage
is competed, follow the procedure starting with the step explained in 1. Operation procedure (1) Starting software rewrite mode
under [9-3-2 Rewriting Software].
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