Panasonic KX-TD500 System Reference Manual page 1433

3.12 System memory error (Major)
Error Code
Possible cause of
the malfunction
Countermeasures
Note
0Axx
xx= 01 : RAM IC 1
08 : RAM IC 8
1) RAM IC of the CPU card failure.
(Including Input/Output bus)
Replace the CPU card*
* It is recommended to have a current copy of the program on disk or tape to
facilitate accurate and rapid recovery.
15-E-15
Enter the system data
End