Baldwin EP 100 - Noise at 200 hz

[mspirit]

Hello, I have this piano for about 5 years. After 4 years of perfection functioning, suddenly one day start produce this instrument very strong hum noise (at 1OO hz and 200 hz), immediately after powering it on. Even if I try to play keys, it works but the noise is still added to tones.
Are some capacitors dead or where should I look for the problem?
Thank you very much! 🙂