My 4-tuner Roamio sometimes has trouble with a local PBS channel that has severe multipath problems. Right now DVR Diagnostics show something like: Signal Strength: 50% Signal Lock: Yes Program Lock: Yes ... SNR: 20dB RS Uncorrected: 2164260735 RS Corrected: 0 Uncorrected errors are not incrementing (much), and reception is fine. But earlier today I saw a V53 error and diagnostics something like: Signal Strength: - Signal Lock: No Program Lock: Yes ... SNR: 19dB RS Uncorrected: 2160000000 [millions less, but I don't remember] RS Corrected: 0 And even with no (useable) signal, the uncorrected errors were climbing wildly. It appears that if the signal goes away, some of the other items just don't get updated, but errors are still counted even though they're meaningless. It doesn't make sense to say that there is no (useable) signal and synchronization with the transmitter has been lost, but yet the unit is locked onto a transport stream and able to count errors and calculate a SNR. IOW, if you disconnect your cable, any SNR shown is just a bogus artifact. And I will mention again that I have never seen the Roamio show any count of corrected errors. TiVo needs to clean up their software.