well i didnt.they did.but let me ask u a thing i never get a clarity from neither here nor yamaha.is electric voltage normal on the body of a yamaha.if yes then why many across same or diff models dont.and if it isnt normal as even yamaha suggests then why is it there on many models.wen i ask yamaha they can never answer.they thanked me for flagging this but even they are confused it seems.
let me ask this ques diff:-
some apple iphone 11 brand new will retain chrg for 3 hrs and sm will retain for 6 hrs.the issue is not if i can manage by chegng more number of times.my ques is,is it ok or not?
please note am not arguing.again trying to understand stuff
Let me be clear about what could be normal and what would not be:
1) Normal: If a digital voltmeter is used, you will typically get a significant voltage between chassis and ground, "real ground, earth.." as TLSGuy mentioned too. That kind of voltage is not harmful unless it is due to something wrong with the wiring, layout, and or components/parts. It is often referred to terms like "phantom", "ghost" voltage.
- In an ungrounded unit, there are always "live" part inside that are in close proximity to exposed parts and/or separated by insulating material that and the non insulated parts of the chasis. Such small air gaps and/or the dielectric could/would therefore act like the dielectric between the the electrodes (the + and -) of a capacitor connected between those "live" parts and the exposed parts (metallic) of the chassis including the non insulated screws.
- Digital voltmeters typically have very high impedance such as 10 MOhm or higher so it will draw very little current and the capitive coupling effects is strong enough to supply and sustain such low current. (example: 0.5 micro amperes for 5 V into 10 Megga Ohm.)
2) Normal: If an analog voltmeter is used, you will typically get much lower voltage but it is important to select the lowest possible range, such as 5 V or 10 V, but not more than 25 V. For safety practice, almost start at a higher voltage range, in your case that means 250 V,, and you will see very little deflection, almost 0, then turn the range to the lowest possible, such as 5, 10, or 25 V but not higher.
Reason: Analog voltmeter may have impedance as low as 20 kOhm if set to say the 5 V range. That will draw 0.25 mA and a typical voltage due to capacitive coupling effects cannot sustain such high current. If you set the analog meter to the maximum voltage range such as 500 V or 1,000 V, it would likely register a high voltage too but it will most likely be still below just a few volts to 5 volts at the most, but again only if the voltage is not from something being defective or poor designs.
3) Normal: You will almost always get different voltages between different units because for an ungrounded devices such as your Yamaha unit, the voltage only exist because of capacitive coupling effects
, and that varies a lot depending on the circuit board and devices layout, size and types of the transformer(s) used. If you get more than a few volts such as 5 V, then there is an issue with either the design or quality control, or even a defective part somewhere.
4) Not normal: If you touch any parts of the chassis, or enclosure, insulated or not and could sense a current passing through your body.
5) Not normal: If you are getting more than a few volts between anywhere including the non insulated mounting screws, RCA connectors etc., and "ground", but again as TLSGuy told you already, it must be a "true ground". If you don't have a known "true" ground that is easily accessible safely then you should leave that job to someone who is qualifed to do it safely.
6) Not normal: If the "leakage" voltage to ground is only 5 V ac or even 10 V ac, and you could feel it then something else is wrong, could be the measuring method, the meter itself or something else we don't know such as if your body skin was very moist, on barefoot and standing on material that is not insulated to ground at all such as concrete, certain tiles etc., instead of wooden floor or think rugs.
So while TLSGuy has given you the short version, I am repeating the basic points he cited but provide you will more detailed explanation.
One thing I would like to emphasize is that you should never touch any non insulated parts of your Yamaha AVR, or even any other electrically powered devices when you are on bare foot or non insulating foot wear and it your body skin is wet or even just moist. This should be common sense, even in countries where the mains voltage is as low as 100 V such as Japan. And by now you should know the reason from your own real life experience.