Betreffende receiver TX-DS838, heb melding in uitleesvenster PROTECT

Get a RCA cable and connect from your amp where it said Sub Woofer in the Pre Out box in the back of the amplifier top left hand side and take it to the "Sub In" located in the back of your Sub woofer bottom right hand (White round connector).
Good Luck!

Are they defined? How do they sound with test tones?

http://www.retrevo.com/support/Onkyo-TX-DS838-Receivers-manual/id/365ag203/t/2/

We can't assume that all has been followed in the manual.

We are an English language website. please repost.

Not worth repairing until the root cause of the failure is proven.
The reason being is that you can have it happen again if caused by any of the devices attached to it, such as inefficient speakers.

The fan in those Audio System only turns at about 1/4 to 1/3 of the ride of your volume control.
It had been intentionnaly designed like that, to achive a quiet operation at low hearing volume.
But if the fan don't move by cranking up the volume at 1/2 to 5/8 of the volume control (with speakers on). You need to have the fan or the fan power circuit checked by technician.
Spider Guy

yes , Im afraid you have a chip gone , If you open the unit up you'll see a alloy heatsink with 4 to 8 large chips screwed to it , These are the amp drivers , In between these chips you see a smaller one (that is the protect chip),You see when things get a little hot this chip is designed to break sooner that the more expensive main amp chips , In the past ive unsoldered these and still found the amp driver bust too ,dont worry though , maplins or even farnell(cpc) on the web will supply these for less than a tenner..If you wanna test my fix then just unsolder the littlest chip on the main heatsink and it should start to work again but with NO protection(unplug it first before taking it to bits)

Go to http://www.retrevo.com/, regsiter for free and search for Onkyo TX-DS838. It will prompt you to download the manual (3.3MB).

I went back and found a loose cable/coax. Re-attached and now the receiver works as good as ever.

The problem here is that the output amplifier section has a problem. This is detected internally and the system shuts down in a "protect" mode. The output section really only kicks in when you attempt to bring up the volume. Another possibility is a problem in the "front end" where DC current is being passed to the amp section. Without takeing measurements, it is difficult to determine the exact cause. This should be a relatively stright-forward repair for a service shop and should cost about $20-$40 in parts plus the local labor charge.
Dan

Same problem here....took it to authorized onkyo repair and cost was $700+ for new board. Got the 707 from crutchfield instead.