Is current leaking from my SX-850?

[ssalvatierra]

I am new to this forum. I am an electronics amateur and collector of vintage audio. I am certainly no expert. I own several old amps, including a Pioneer SX-850. The unit was a dud when I bought it but I replaced the power board and now it works like a champ. Recently, I noticed that when I touch the aluminum faceplate, I feel a very slight buzzing sensation in my fingers. This occurs even when the amp is turned off. When I simultaneously touch the steel chassis, the buzzing sensation stops. Also, if I rotate the plug in the outlet (change the polarity?), it goes away. What is causing this? Is it a safety hazard? Do these units have a grounding problem? Is there a reason why they don't use a grounded outlet? I appreciate any insight you can provide on this topic.

 

[w1jim]

You figured it out - rotate the plug.
One leg of the power line is tied to the chassis with a high (meg ohm) value resistor.

These receivers predate the common use of three prong grounded outlets.

Enjoy the SX-850, I've had a couple and I think the price/performance ratio on these is superb.

 

[ssalvatierra]

Thanks for the very quick response! I am glad to hear that the buzzing sensation is normal. I agree with you - the SX-850 is a fantastic amp!

 

[audiojones]

Yep, common issue and nothing to worry about. The SX-850 is an awesome receiver and IMO it's where the best line Pioneer had to offer begins. Enjoy and cherish it, nothing built like that anymore!

 

[whoaru99]

Some leakage is acceptable by standards, but too much is not. The concern is the amount of leakage current.

Whether the amount of leakage current in this case is safe or not safe should be established by measurement. The exact process and go/no go criteria is likely written in the service manual.