Hafler 915 Preamp Phono Upgrade

Hi,
Does anyone know where I might get the Phono upgrade kit for a Hafler 915 preamp. I have resurected the preamp and like the sound. I think it was built in the early '90's.

I believe it comes as a circuit board and installation is pretty simple. Have tried various sites and eBay but nothing showing.

Thanks for any suggestions.
Conor