Mechanical Chime Buzzing

tldr: mechanical chime still buzzing after replacing transformer and chime Installed 2 Video Doorbell 2's in 2019. They are hardwired and use an existing mechanical chime. They worked without issue, though the batteries seemed to drain quick despite being hardwired. Last week, woke up to the chime buzzing. I replaced the transformer, which reduced the buzzing, but it didn't go away. Replaced the chime, which didn't help. I've read about solutions to this problem ranging from using a resistor, power pro kit or replacing the doorbell. Anyone have an idea before I start randomly buying things again?