On 2026-08-02 5:39 a.m., Tony Miklos via Jukebox-list wrote:
On 7/29/2026 7:35 PM, John Robertson via Jukebox-list wrote:
Hi Mauro,
If it all works fine on the bench then the setup in the machine must be the problem.
Check that the volume control box and the mechanism chassis aren't 'Hot' - connected in some way to the 'mains!
Set your meter on AC volts suitable for your line power and touch one lead to the volume control box and the other to earth ground. Should not be over a few volts leakage no matter which way the power plug (if reversible) is inserted. If good then check the metal chassis, as well as the tone arm and amplifier.
Here is a link to make a simple leakage detector which is a step up from the above crude test procedure.
🔗 https://www.flippers.com/pdfs/ElectricalSafety/Electrical_Safety_Testing.pdf https://www.flippers.com/pdfs/ElectricalSafety/Electrical_Safety_Testing.pdf
John :-#)#
I don't like the idea of the loading resistor in that tester. I've had chassis that give that little *buzz* shock when touching the juke and the resistor can ground that out. When I've ran into the hardly noticeable buzz, I'll measure from ground to the chassis. The buzz some of us feel sometimes can be "shorted out" by simply grabbing onto the machine instead of just your fingertips or whatever body part is barely touching the machine using a cheap DMM without enough ohms/volts. I've been there and done it. I now always use one of my higher end meters to do that test. Often the chassis to a real ground is as high as the line voltage, yet not give a hell of a shock. It's so mild that your body's conductance to ground can *short* it down close to zero, yet unnerving to others. The cheap meter can measure close to zero volts from chassis to ground, but a good meter can measure as high as line voltage.
The test was designed to show if the voltage leakage was potentially (yeah, I know!) dangerous to the consumer, not if you just got a slight tingly buzz. I consider the test to be an excellent safety test to see if a chassis is 'hot' enough to risk a serious/tragic shock. Note it was professional Electrical Engineers who made this test, I trust their reasoning in the matter of electrical safety. I have a Hi-Pot tester in my shop that we use to check line powered equipment to see if they can trip the safety switch when 1500VAC is resented to the power cord and all exposed metal is checked with the probe. Not everyone has this expensive tool so I consider the resistor test as the next best one...
Some light reading (check page 33):
https://www.psma.com/sites/default/files/uploads/estguide2.pdf
John :-#)#