Hello Neosteo,you didn't state the issue with your amplifier but I do know the 3 series amps the have power supply capacitor leakage issues. I owned a 331 myself for a while.
I do remember removing the bottom cover and the caps reside in the four corners of the chassis, if this is the issue then access is not too difficult and perhaps you could replace them yourself, replacing the original caps was an expensive exercise but can be got around with a matrix of smaller capacitors to make up the value which will sound better as well.
This series also have a built in power conditioner, a good place to look at for power issues.
I would also consult with a few different repairers as costs and expressions of interest in the repair could vary widely.
Personally I was happy to ditch my 331, I went to tubes and never looked back. in my opinion the 3 series were neutral and controlled but also to me were a bit introverted and shut in.
I do understand why you purchased your 333.5 but I couldn't presume to tell you what to replace it with if you desired to do so, the subjective application of your levinson may well still exist.
I hope this helps you in some way, I've been there.Sucks
