HELP! Higher Fidelity Industries HF-138 shematic

Hello folks,
I came across this amps. To make sure its serviceable I would need the full shematic. It should indlcude the driver and output stages as well.

I am more concered about the output transistors. Which type did they use and about the availability of the parts now.

The same concerns I do have about the driver stage with the availability of parts.

Please help
Stefan