Audio Systems: AIWA NSX-D707 - no display - hum when on, aiwa nsx, line level input

Question
At Bottom:

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Followup To
Answer -
Dear Don,

Are you using an auxiliary 110/120 outlet on the rear of the Aiwa to provide power to your auxiliary unit? If so, that shouldn't have any effect on the unit's power supply, since auxiliary power outlets are simply pass-throughs from your house current's outlet. Otherwise, simply feeding a line level input into the Aiwa has nothing to do with the Aiwa's power supply. Theoretically, then, there should be no relationship between an auxiliary unit and the Aiwa's power supply.

(This is different from, say, a USB device which draws its power from a PC's power supply.)

If the display panel's darkening is directly related to the connection and disconnection of an auxiliary unit (i.e., it happens every single time), you may be seeing a symptom of something else slowly failing in the Aiwa. I suggest you take it in to a reliable repair facility for a bench test.

Good luck. And thanks for choosing allexperts.com!

Kindest regards,

Kevin

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Follow up:
Kevin,

I appreciate the assistance, but I have a question based on your answer.  

I am not using a secondary plug to power the auxillary unit.  The one plug powers the entire unit.  

The connectors between the two units are pretty tiny....  They look pretty low voltage to me.  

If this is the case plugging in the second unit would task the power supply found in the first unit even more, causing it to get darker and darker?  

I struggle with this as I do not wish to trash the unit, and nobody can service it as it is a US product that was sold in Canada....  

Thank you,
Don

Answer
Dear Don,

No, even mini-jacks will not task your power supply if the auxiliary unit is independently powered, which you say is the case.

I'm 99% sure that you do not have a failing power supply. What you describe is symptomatic of a shorted circuit, which could be anywhere inside the unit. That's why I suggest you have it bench tested. An independent hi-fi repair service can help you. They don't check the nationality of sales slips.

Kindest regards,

Kevin