I have 3 year old Harman Kardon AVR 745 receiver. Recently it is getting turned off just couple of seconds after it is turned on. I tried resetting it and also moving it to different outlet.
Make: Harman KardonModel: AVR 745
Tried resetting and moving to different power outlet
Hello, I am here to assist with your HKCustomer
There are several reasons why the unit may turn off immediately, it seems you have checked that the memory is reset to defaults. This leads to the possibility of the receiver going into protect mode.
The receiver has circuitry to prevent it from tranfering DC current to your speakers. This is why you do not hear anything after initially turning the unit on. The receiver may be sensing that the DC offset is too high and shutting down, now there are other causes, if one or more of the output devices have failed (FETS or IC's) this will cause this issue as well.
Here is what you can do if you have not tried, disconnect all of the speaker wires, then try a reset again. This will rule out a possible shorted speaker cable. even a hairlike strand going from positive to negative will be enough for the unit to sense a short.
Also check if there are any error codes as it is powering up, or any scripting that is not normal.
I tried following things, but it didnt help.
- Remove all speaker cable and reset the receiver
- Remove remaining input output cables and reset the receiver
Also I dont see any error codes or abnormal scripting while power on.
From this point, since the unit is does have power (even for a minute) it will have to be diagnosed further. This means invasive, with a DVM, oscilloscope and taking the unit apart, also the proper service manual will be needed as there are none free on the net.
Unfortunatly there is no "quick fix" for this issue, and it will have to be serviced. There are three areas of focus: On the older model AV units there were several service notes with regard to the memomy and microprocessor. If the unit was plugged in and a surge was felt (storm or other) the power supply may have a fault with a bad lower voltage regulator. Lastley one of the output devices failed.
Here is a link to the support page for your unit, you can find a service center near you.
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I bought the system in US, but 9 months back I moved to India. In India it is 220V, so I got a step-down transformer (5000Watt) and connected Belkin surge protector (110V bought in US) to it. Then I have plugged my Receiver, TV (also 110V, bought in US), etc into Belkin surge protector. From the begining Belkin surge protector showed fault and line protected indicators instead of clear green, line-OK indication, even though transformer output was 110V. Going forward after I get my Receiver fixed (if I can get it fixed here), what is the best way to plug it in to the power source. Power quality is not good in India. Power goes off frequently and fluctuates. But I was depending on Belkin surge protector to protect it, but may be it is not suitable for Indian environment. Your advice is appreciated.
I use an APC ups/ power conditioner. This will boost and buck transient voltages to raise or lower to the appropriate voltage. There are other "audiophile" type conditioners, but I do not subscribe to some of the hype, or cost/value. A good 220 volt (750volt amp) or higher should do the trick for your system. Then step down with your transformer. Belkin also makes a power conditioner as well.
BS Electronics, 19 years medical equipment service, design and construct home audio amps