KX-NS700 rebooting 5 times a day after 7 years

[phones001]

We have a client with a KX-NS700 and one expansion cabinet with around 40 digital phones. No IP devices at all. The unit is now rebooting about 5 times a day after 7 years of working fine. I am thinking it is maybe the power supply but nothing in error log that is helpful.

Where can I purchase the power supply as my distributors all say it is discontinued?

Any way to determine what is causing this as no changes have been made when this started?

Thanks

 

[ingy500]

replacing power supply ns700 to expansion 720 to make sure