K8099 Nixie clock issue

After several years of reliable service my Nixie clock has died. In troubleshooting, I have verified both 5v and 12v supplies but no HT supply. The HT voltage is measuring ~14.5v. My first thought was bad MOSFET so I replaced it. Still no luck. I have found that the PIC and the 7805 regulator run very warm to the touch. When the PIC is removed, the 7805 is cool to the touch. I suspect I’ve cooked the PIC. Is it possible to still get a replacement PIC? I know this is a discontinued product.

Thank you,