Looking For Fairchild Transistor

I'm working on an obsolete Crown CTs-2000 amp which has blown output transistors. They carry the designation B0410, QP, and 17N40. Wondering how to obtain replacements (or a service manual). Thanks in advance for any help you can provide.

Might it be a FQP17N40 MOSFET?
Those seem to be available in online places like Newark, Mouser, etc. Not sure about stock levels however...

Great - thank you. I was researching the top number and thought the 17N40 was "manufactured in 40th week of 2017". FQP17N40 is a valid Fairchild/onsemi part number and is available through Digikey.

My Digikey was out of stock. Mouser has them in stock in Canada. Your country may have different stock levels.
Before replacing them, I would first look into why those all blew in the first place. Maybe a bad power supply?

Yes, found several bad caps and I checked the cap/resistor network on the output where the cap sometimes shorts. I appreciate the tip.

Not familiar wit the CTs-2000, but from the picture it looks a bit like an iTech series (crown have juggled the names around and I'm not sure what goes under what names now). I believe it's what they call a "balanced current amplifier".
Crown are pretty good at releasing manuals for obsolete products, but there were none available for this (more recent) series last time I looked. However, the topology is very similar to the K1/K2 series - and their manuals are available on the Crown website, and well worth a read if you're not familiar with this unusual amplifier topology.

I'm sure I don't need to tell you to check all the drive circuits carefully, too!
Let us know how you get on.