Entertainment Center: TVs, Stereos, VCRs and DVDs - Harman Kardon AVR80 MkII Left Channel Only

hi there,
i have the similar problem but recently it is ok but now, only left channel is working, right channel has no output at all. Do you all know what could be the root cause? btw, do you have the service manual with schematic that you can email me?
listening in mono now :(
- jims

Hi Jim,
Welcome to the forums! I moved your question into its own thread.

Have you done the basic troubleshooting to be sure it's the output channel and not your cabling or speakers? Swap the speaker cables. If the right channel now works, you have a bad speaker cable or a bad speaker.

Also, be sure the right channel input is working by swapping the RCA cables or switching to FM radio.

If it still doesn't work, you may have a blown output transistor or a sticky protection relay.

Hi Rick,
I have tried swpping the speaker cables and RCA frm my CD player, even with only one channel RCA , only the left channel ouput is working.

Where and how can I look for the "blown output transistor or a sticky protection relay"? Do you happened to know anyone that has the service manual schematic?

thanks again.

I did a few searches and came up with no schematics for that device. Sorry.

i know that there is a website selling pdf copies of service manual, but kinda expensive though.

https://www.manualzone.com/ShowProductsForModel.do?model=M44845553

i will try to open up this weekend to have a check on the inside. But whereabout is the "output transistor or a sticky protection relay" ?

Your choice whether to buy the manual, but weigh the cost of having a pro repair shop take a look at it and at least diagnose the problem so you can perform the repair. (Of course, you then have to choose whether it makes sense to dump money into a repair or replace the unit with a new one.)

The transistor(s) will usually be a TO can mounted to a heat sink. You have to pull them to check them properly. When you replace them or put them back, also replace the heat sink goop. If they have inserts to isolate them from ground, make sure it's properly fitted or you'll short them to ground.

The relay is usually a mechanical cube relay mounted on the main PC board. It's rare that it sticks, but worth checking. You'll hear it click after you power up the device. There could be one that handles both channels, or two -- one for each channel.

I know I'm not much help on this one. I don't think we have a certified audio repair tech on this board.