It's a Denon AVR-S900W. The front left channel died and I can't seem to get it back. Its powering a 5.2 system (Polk center, book shelves and in wall surrounds. Unknown subwoofers (15" and 12"").

I'm looking for suggestions on a replacement.

I'm in the process of looking for a receiver myself. Currently deciding between the Denon X3800H and the Onkyo RZ50.

I'm in the same boat. I'm having issues with my receiver. Having been out of the home theater scene for many years now, I have no idea what to replace it with.

It died TWICE?

Yes. It was very tragic. And expensive. I'm trying to save for night vision stuff!!!

My Denon AV receiver lasted 8 years and then I replaced it with a Yamaha Aventage RX-A1000 that lasted 12.  It just died and I replaced it with a new Yamaha Aventage RX-A2A and it's sweet.

Also have a Samsung soundbar in another room,  but the Yamaha stands tall with a ton of features.

Denon AV receivers tend to have class leading objective performance out of the mainstream brands.  But that's actually not a big deal, as we're not lab equipment, and we're unlikely to run these things loud enough for the differences in distortion to become audible.

That said, Denon also uses Audessey room correction, which IME works really well. Onkyo uses Dirac now, which is supposed to be better, but requires more manual tweaking.

Yamaha has the most responsive phone app remote, and it opens quickly, and is stable. Denon's phone app remote is very buggy, and takes like 5 seconds to open to the point it's usable. YPAO is a decent room correction system IME as well.

Sony and Pioneer use in house room correction systems, and IME they're not very good, and only level match, no PEQ.

I've never owned a Marantz AVR, so I have no opinion on them.

replace that channels MOSFET

much cheaper

I’ve been happy with my pioneers, no issues and bought cheap on eBay. 5.1