05-10-2013, 04:36 PM
I would guess that it is an isolated power supply and that the deck should be earthed.
I would go for a set of cold tests with a continuity tester between the deck and arm metalwork to the ground pin on one of the input connectors.
If there is a missing earth it is common for the hum to change when metalwork on the deck is touched.
I would go for a set of cold tests with a continuity tester between the deck and arm metalwork to the ground pin on one of the input connectors.
If there is a missing earth it is common for the hum to change when metalwork on the deck is touched.
