Forte 4a service

I have an opportunity to buy a used Forte 4a and understand that they used IBGT transistors, which are no longer stocked by the manufacturer. I also understand that Jon Soderberg of Vintage Amp Repair used to service these amps and had some stock of the IBGTs.

Soderberg's website is no longer working. Does anyone know if he is still in business? If not, are there other avenues for service or for the IBGTs?

Many thanks!