942 will not tune one OTA channel

[wtb955]

Several months ago my 942 stopped tuning one particular OTA channel. A Dish Network Advanced Technical Support Technician suggested I install a DC block and a RF attenuator which I did. This corrected the problem until recently when the 942 again stopped tuning the channel. My 921 still recognizes this channel and the 942 shows a signal strength of 100, but the channel will not tune! Does anyone have any suggestions? Thanks for the help!
Tom