I do not know if it is worth repairing a 25 year old amplifier. Obviously, you have to get an estimate to repair your current Levinson 331 amp.
This raises several questions. Are comparable parts available to make the needed repairs and, if repaired, how long will it last? Does the Tech have the needed skills to make these repairs. Will the amp require additional repairs in the short term. Are the other parts in the amp, wires, caps, etc. okay or do they also need work. Your estimate needs to a complete checkup of your amp. Will the repaired amp sound as good as the original amp?
If you decide to purchase a new amp, will you get better performance and how much will it cost.