I'm looking some info on a diode that has cracked and the only thing about it is that its D788 in a Harmon-Kardon AVR 335

Try using the RCA outputs once and see if that works..One other thing don't use the phono input on the receiver as it could damage the amplifier

I would try disconnecting the speakers, then turn it on. If protect still shows with no speakers connected, then it needs to go to the repair shop- Might be a blown power transistor.

Probably was damage buy a power surge, Internal damage to (Reciever)

Register and download the manual for free at retrevo.com

http://www.retrevo.com/support/Harman-Kardon-AVR-7200-Receivers-manual/id/386ag101/t/2/

Page 17...

To clear the AVR 7200

Hi if there is an optical out on the television i would use that direct to your Harmon Kardon AVR 125, the sound would be in sync with picture, as the source is the same.

try this link http://www.rapidonline.com/Electronic-Components/Resistors-Potentiometer/Low-Ohmic-Resistors/4W-Low-ohmic-resistors/65206 its in uk
the order code you will need is 62-7108 for that store
good luck

$12.43 on eBay!

harmon kardon AVR 154 Remote Control eBay

and others. Amazon sold out.

Replacement Remote Harman Kardon AVR 154 Google Search

Hello

Yes, there is something you can try, to know where to look for the problem if this happens again. If the receiver is still under warranty, just send it back, otherwise, open up the amp and trace the path back from the speaker channel to the capacitors on each channel, this is usually the problem(you should be able to see if it is blown, cheap to repair).

If all the channels went out at the same time, there is something wrong with the central unit, to repair that, if it is not the above problem, cost expensive.

Hope this can help you.

Kind regards
Andrea

http://www.starchoice.ca/english/customercare/techcentral/remote_controls.asp

Look here for the codes to whatever remote you have. The chances are there arent any though. Harmon Kardon codes are a very unique signal that most remotes cant duplicate. More than likely you are going to have to use the original Harmon Kardon remote.

I also had this UNLOCK message on my Harman Cardon AVR 130.
The reason for this error was - in a hurry I've plugged the optical input into optical OUT! Double check that your connections in the back are correct and hopefully it fixes your problem.

Cheers,
Sergey