They generally seem to be pretty bulletproof if you were willing to replace the hard disk occasionally, I suspect most of the remaining ones were deactivated during HD upgrades. I've had my DSR6000 in daily service since the fall of 2000, just before the dual tuner feature came out.
My "secret" to long life was to replace the original fan with a Papst 612N/2GML along with a 3 Pin to 4 Pin Adapter for $28 back in Feb 2004. The adapter allowed the fan to be powered by the 2nd hard drive cable, rather than the motherboard connector.
Series 1 DTV/TiVos:
Edited by fairsailing, 20 November 2009 - 10:45 AM.
added equip list