As far as Pioneer USA is concerned, they never ever made any such thing as a DVD/HDD recorder, they don't even know what one is, and please don't bother them about it any more because it makes them anxious (IOW, they're absolutely useless as a repair resource). Post-2008-recession Pioneer is a forlorn place staffed by terrified souls: best to leave them be.
Your Pioneer 640 with the remote blindness may have developed a short in its IR receiver circuit, the receiver eye itself may have gone bad, or perhaps something has gone funky in the motherboard controller. If a hard reset did not fix the issue, it may be unrepairable at this late date unless you get lucky and the local repair center has a compatible spare IR receiver they can try in it. All diagnostic systems built into Pioneer recorders are operated by the proprietary Pioneer/Sony service remote: if the unit is IR blind, troubleshooting the problem could be very difficult.
Your Pioneer 640 with flaky signal output probably developed a short or cold solder joint in the connection panel, causing sporadic output signals. This is something most repair shops can troubleshoot and fix at reasonable cost: its a common occurrence with modern AV gear that tends to have very flimsy structural support for the rear connector panel (although the front panel connectors are usually the first to go).
Theres a small chance that either or both 640s have developed "tin whisker" syndrome, a consequence of the stupendously idiotic and draconian regulations the EU foisted on global mfrs some years back. This edict effectively banned durable, traditional leaded solder in favor of "lead-free" solder and circuit board traces. Of course, nobody bothered to ask electronics engineers before rushing that legislation: if they had, they would have been warned that lead-free circuits are inherently unstable and tend to grow a microscopic outcropping of tendrils ("whiskers") that short against other nearby circuit traces. This is not repairable, and the reason why the new symbol "10" in a circle of arrows began appearing on all electronics and camera gear: the "10" means the mfr can't guarantee against tin whisker syndrome longer than ten years at the outside, and the arrows mean you'll likely need to recycle the item by its tenth birthday.
Last edited by CitiBear; 06-07-2017 at 07:52 PM.