On Power Up the system prints the power-on banner but is hung

[Blacklord]

A whining noise will be heard. Only on hi-profile models, the power supply case is touching the voltage regulator by the cassette port. Bend it down more. This can also be caused by an 8088 board touching the power supply of early model power supply units which were bare steel (later models were insulated with paint to prevent this). Use clear packaging tape to form an insulation at the point of contact on the power supply case.