Spare part air con Hitachi controller board

[okay52 0]

Dear Readers,

I am looking for the spare part electronic controller board of Hitachi air conditioner (indoor unit model RAS-13CZ2). It is old unit and Hitachi doesn't carry the part anymore. I wonder if anyone knows where to find the part from second market? I was told some big aircon sellers, e.g. Gain City, Best Denki, etc, keep old units in their warehouse after their contractors have installed new units and take back the old units.

Thanks.