Re: Kenwood KDCX817 issue
Yes, it's the ribbon cable. The same thing happened to my X717. I replaced the cable by following the directions that was provided in an online tutorial. However, the thread was removed several months ago so you're kinda stuck. I did a bonehead trick(don't ask ) several months after I fixed the HU and I ruined it for good.
My suggestion is to do what I did...get the Excelon X589 from Locust Audio(on ebay) for around $160 shipped. The '05 units are better in two very important areas....SQ and Kenwood's decision to FINALLY drop the stupid and troublesome D-Mask feature. The new units have a motorized face.
I went with the 589 since it had the same features as the 717 but the 789 and 889 are very sweet-looking HU's as well. They're also a little more money. It's your call...Good Luck.
Kenwood eXcelon KDC-X589 HU
Aura MR 6.1 comps
Aura MR62 Integrated comps
Ascendant Audio Arsenal 12(sealed in 1.2 cubes)
US Acoustics USX-4065(65x4)
PG Octane 8:0.1(600 watts x 1)