Sunn Solid state amp not repairable?

[agedhorse]

TO3 transistors we’re often mounted using sockets, mainly for mechanical reasons.

 

[brianrost]

The power transistors are on sockets. You don't find that often these days.

That's because the need to swap transistors has been pretty much zero for a long time. I worked as an electrical engineer for four decades so I've seen a lot of changes in PC boards over that time.

The final nail in the coffin on easy repair was surface mounted components. Through hole PC boards are pretty easy to work on.

 

[agedhorse]

Components have gotten much more reliable and the design skills (including margin analysis) is far better too.