I'm a little confused. You say "purchased a Pioneer VSX1020 reciever and tried to run the cable box signal from a Cisco Explorer 8640HDC via HDMI cables through it without success." Then you say "am using HDMI cables from box to TV". Which is it? Do you have your cable box connected to the receiver or the cable box connected to the TV? You should connect the cable box to the receiver with HDMI, then your reciever should be connected to the TV with HDMI using the single "HDMI Out". All other HDMI devices should use the receiver's "HDMI In" ports.
I just purchased a Pioneer VSX1020 reciever and tried to run the cable box signal from a Cisco Explorer 8640HDC from Time Warner Cable via HDMI cables through it without success. It reads "no signal" on the TV screen (52" Samsung 1080p). I have rechecked all connections, am using HDMI cables from box to TV, selected the appropriate HDMI channel for cable box input on the user menu. Does anyone have other ideas with this?
The reciever is amazing by the way, great 5.1 channel sound using Yamaha speakers, and Blue Ray is a theater like experience. Hope to be able to watch movies and sports from the cable box soon!