This is a very difficult situation. Please search on mark Levinson repairs and see what comes up. For examine, I found:
i suggest you investigate these repairs shops and determine if the cost to repair is worth it. In some cases, you repair something and shortly after that, something else breaks. I do not know the age of your #331 amp. You have to evaluate the repair cost vs. the reliability of a new amp.
IMHO, Based on the response from Mark Levinson, I suggest you look for a new amp and a company that supports your purchase.