yamaha Avr with electric current on body

[lovinthehd]

its totally fine.i checked using multimeter too.i think u may have missed out on the earlier part of the conversation or u may havent got the context.i am getting the same voltage over the receiver at
1.my home
2.cousins home 3kms away
3.friends home 8kms away
4.yamaha authorized service centre

i had already given these guys the details and had told them that its not any problem with local distribution.thats wen they told me lets check at our authorized service centre to confirm.thats why i took it there and there too the same issue repeated.so now u understand how dishonest these guys must be to again suggest this.
for measurements
neutral phase= 230v
phase ground=230v
neutral ground=0v

thats the reading at 2 homes that i tried.the guys at yamaha management in india are just bluffing and trying to wash their hands off this as already i said which jonone seems to understand.they say 3 things:-
1.our devices dont have this leakage.ask them why other similar or diff models have..and thats when they say

2. on all our models a small voltage is there.ask them why then similar or other models at least across india dont have them and then they will start speaking bullshit

reason nobody however smart they may be cant logically ever explain such a huge variation across models and across same models.
we can go round and round trying to blame local voltages etc etc but the fact is yamaha either knows that theres sm sort of design flaw that has been causing this or better there QA simply sucks.
Since they cant and wont and wven those who have it dont ever report or hold them accountable this thing keeps repeating.
only drilling a service centre branch head made hik finally accept that this is an issue and that they will definitly escalate it.now will they or not is smthng else

Doesn't particularly addessmy question...start with describing each homes' central ground and that nothing deviates from such...Personally still suspect your infrastructure...

 

[sand87]

Doesn't particularly addessmy question...start with describing each homes' central ground and that nothing deviates from such...Personally still suspect your infrastructure...

ok wat about their service centre which they claimed works perfectly?u wud suspect the infrastructure of 3 homes and a yamaha auth service centre but still not the avr huh.

 

[sand87]

Doesn't particularly addessmy question...start with describing each homes' central ground and that nothing deviates from such...Personally still suspect your infrastructure...

the problem is that the sellers, the dealers,heck even the service heads claim that almost the models they have has this voltage and then u also have same models thatbdont.so go figure.thats wat i said.yamaha knows fully well the issue but since it can hoodwink customers they continue to do that.

 

[lovinthehd]

Personally I'm just not convinced you have the complaint against Yamaha you think you do....and you haven't answered my questions.

 

[sand87]

Personally I'm just not convinced you have the complaint against Yamaha you think you do....and you haven't answered my questions.

well if apple says that their phones have a speaker issue but the apple fans insist no its their ears then wat can one possibly do rt!!

i dont know if u havent read or not but mail after mail yamaha clearly says this is a defect.their other devices too have it confirmed by their dealers and service centres.yamaha management wont because either ways they then are screwed but over the phn they say both.its like they are self contradicting.
and regarding ur questions u havent still replied as to if u doubt yamaha authorized servcie centre too who checked it at their premises for this fault and confirmed its there on mine and couple of other devices they had there too.infact they showed me.now if u wont trust yamaha authorized servcie centre too then wat can i say.

 

[sand87]

Thank you, now I have just a few more questions, or tests:

1) Exactly which part did you touch when you got that "tingling sensation"?

2) Did you get that sensation every time you touch it, and what if you touch it with you finger, remove it then touch it again right away, would you get that same sensation again, and how long would that sensation last?

3) When you get 10 V with your multi-meter, where did you put the red and black probes and did you set it to AC or DA?

If you answer to Q2) is that you get the tingling at first touch, but if you keep touching for say a second, you didn't feel it anymore, and then remove your finger, touch it again within a second and you still don't that tingled, then I would say it is just static electricity you were getting. If you get the same tangling sensation every time you touch it within a short time then for sure it is a continuous leakage current, that may or may not be normal. I would know for sure if I were there to do some test but I am not.

To be on the safe side, I would say regardless, 10 V across the part that you got a shock, and a known ground, such as the ground at the wall outlet does not seem normal. Though depending on the design and the cabling layout, it could be just a capacitive coupling effect. In an extreme case, I have seen up to 50 V of phantom voltage due to capacitive coupling effects on a very long cable. Obviously you should never experience such extreme case in home applications, I am just using an example that phantom voltages are more common than people think.

By the way, 10 V is obviously voltage, not current but I think you know that. What you may not know is that a digital multimeter, and your screw driver tester, typically have very high input impedance so sometimes they can give you a false alarm because the very low leakage current through "normal" capacitive coupling effect could show a pretty high voltage, yes even 10 V is possible depending on other factors, and such normal leakage current could even light up some small neon light indicators and give you a false postive.

It is unbelievable that it is so hard to contact Yamaha, but a quick way to find out is, bring you multi-meter and your screw driver tester to your nearby store that has the RX-V685 and see what you get. If a second unit behaves the same, that should give you at least some peace of mind that it may be normal, while waiting for Yamaha to confirm.

@PENG

So after ao many days i finally went to a yamaha dealer 4hrs away from my home who agreed to let me check the avrs.
i could check a newly arrived RX-V685,A880,3073(demo piece)and an integrated amp N602

V685 - 3-4V potential but less than on mine which is 5-10V
A880-5V potential
N602- didn't measure but seems less as the tester glows barely
3073-no voltage.the tester does not glow at all.

only thing making sense or doesnt is as the model grows in power so does the voltage on the body and also some users don't see it.dont know whats wrong at yamaha.even dealers were surprised

 

[dos.or.die]

Hi Everyone!
I just registered for the same issue you are having with your Yamaha Receivers. But mine has a lot more voltage on the chassis. I measured round about 120V RMS AC when it's floating !

Today I hooked up different speakers to my Yamaha RX-V775 and got an electrical shock from a speaker wire while the unit was turned of. I investigated and found that the chassis is floating at quite a high voltage. I took it up to the bench and made a few measurements. I documented everything on this 6 minute video:

I'm pretty sure that is not normal (right?). I am going to attempt to fix that issue. But before I open the unit up I wanted to have some opinion what could cause this and what to look for. My best guess would be to check the power transformer first. Any tips what to look for / test ?

Any help is highly appreciated!
Thanks
dos

 

[sand87]

Hi Everyone!
I just registered for the same issue you are having with your Yamaha Receivers. But mine has a lot more voltage on the chassis. I measured round about 120V RMS AC when it's floating !

Today I hooked up different speakers to my Yamaha RX-V775 and got an electrical shock from a speaker wire while the unit was turned of. I investigated and found that the chassis is floating at quite a high voltage. I took it up to the bench and made a few measurements. I documented everything on this 6 minute video:

I'm pretty sure that is not normal (right?). I am going to attempt to fix that issue. But before I open the unit up I wanted to have some opinion what could cause this and what to look for. My best guess would be to check the power transformer first. Any tips what to look for / test ?

Any help is highly appreciated!
Thanks
dos

well first of all measure
1.phase-neutral voltage
2.phase-ground voltage
3.neutral-ground voltage.

Note the neutral to ground voltage.its should ideally be zero or a bit more but if it isnt then you can move out the possibility if a faulty ground because if you take it to yamaha thats the first thing they will try to out the blame on.

 

[TLS Guy]

Hi Everyone!
I just registered for the same issue you are having with your Yamaha Receivers. But mine has a lot more voltage on the chassis. I measured round about 120V RMS AC when it's floating !

Today I hooked up different speakers to my Yamaha RX-V775 and got an electrical shock from a speaker wire while the unit was turned of. I investigated and found that the chassis is floating at quite a high voltage. I took it up to the bench and made a few measurements. I documented everything on this 6 minute video:

I'm pretty sure that is not normal (right?). I am going to attempt to fix that issue. But before I open the unit up I wanted to have some opinion what could cause this and what to look for. My best guess would be to check the power transformer first. Any tips what to look for / test ?

Any help is highly appreciated!
Thanks
dos

That was good information. I suspect that the fault is in the starting circuit. That is the only circuit live while the unit is off. Obviously there is a high resistance from the AC line, as you could not draw much current from it, and the main fuse does not blow. I'm suspecting there is a leaky cap in the staring circuit that is activated by the on button, which is a momentary switch. These circuits are always flip flop type circuit, often an unstable Darlington pair, or some such and probably contained in an IC.
This may be difficult to sort out without a circuit.

On researching this a little further, I understand that these days the circuits most commonly used employ a COSMOS logic chip.

This is a more traditional type latching circuit.

This is apparently how it is more often done now.

However there are a lot of possibilities these days, so you will need to acquire a service manual.

 

[dos.or.die]

Thanks for your inputs! (TLS Guy and sand87)
I was thinking about it for a while and got the service manual with the circuit diagram and I think I figured it out.

Here is what I think is happening:
The two Y-Capacitors for EMI-Filtering right on the AC-Input make a capacitive voltage divider. Due to the leakage current a voltage of exactly 1/2 AC-Voltage accumulates on the chassis with no way to drain. The Caps have a very high resistance/impedance so that only very little current can flow (200 micro-amps measured). The accumulated charge however can give you a "surprise" when you touch it. I grounded the chassis via the phono-ground terminal to a protective earth connection and all should be fine.
Yamaha saved 50cent by not putting a proper IEC-Connector on the unit and make their customers suffer

I also made a Video with the diagram and some explanation:

Please let me know if I got it all wrong. I'm not an expert after all.

Thanks!

 

[TLS Guy]

Thanks for your inputs! (TLS Guy and sand87)
I was thinking about it for a while and got the service manual with the circuit diagram and I think I figured it out.

Here is what I think is happening:
The two Y-Capacitors for EMI-Filtering right on the AC-Input make a capacitive voltage divider. Due to the leakage current a voltage of exactly 1/2 AC-Voltage accumulates on the chassis with no way to drain. The Caps have a very high resistance/impedance so that only very little current can flow (200 micro-amps measured). The accumulated charge however can give you a "surprise" when you touch it. I grounded the chassis via the phono-ground terminal to a protective earth connection and all should be fine.
Yamaha saved 50cent by not putting a proper IEC-Connector on the unit and make their customers suffer

I also made a Video with the diagram and some explanation:

Please let me know if I got it all wrong. I'm not an expert after all.

Thanks!

I think you are absolutely correct. However that is a disgraceful design and totally unacceptable. That is a huge black mark against Yamaha. That can not possibly meet prevailing standards.

The world really is becoming awash in absolute junk.