Panasonic KX-T336 System Reference Manual page 543

3.07 Expansion shelf power down ( AC )
Error Code 051n
n =
1
: Expansion Shelf 1
2
: Expansion Shelf 2
Possibk cause of
the malfunction 1) Power failure
2) Power Supply Unit malfunction of the Expansion Shelf n (n=l or 2), or trouble
with the Power Supply System (Backboard, CPU card) of the Shelf
Countermeasures
..I . .
Is there a new error message in the
1 F;;rozd;hen th;rSET button / I Yes
Does the trouble occur frequently ? 1
I
No
Yes
Replace the Power Supply Unit 1
No change in
..OK
condition
Y
I
Replace the CPU card*
No change in
OK
condition
Y
Replace the Shelf
^_.
I
I
l
It is recommended to have a current copy of the program on disk or tape to
facilitate accurate and rapid recovery.
14-E-10