7216 STB not working 8888 and blinking LED (upper right)

[aerospacecase]

I went through all the web site diagnostics, but the STB keeps cycling: 8888 for about 10 seconds, then the upper right LED blinks twice a second for about 55 seconds. Pulling the power plug, waiting 30 seconds, then plugging back in makes no difference.
I got on the phone with a support rep and he went through everything he could to fix the problem, to no avail. He sent me a new box and it is doing the same thing. I did not fiddle with the coax cable before the problem occurred. The other box in the house works fine.

[Hubrisnxs]

use your remote, and see if you can get into the diagnostic menu.  

Point the control at the tv and hit STB power and then OK OK

you want to look for a screen that looks like this, and select INBAND STATUS 

Once you go into inband status, check the INBAND SNR RATE.   if it's 0 or NA, then that means you have a problem with the wiring.   make sure it's plugged into FiOS TV IN on the back of your set top box, and that the other end goes securely into your FiOS TV Splitter.  Try replacing the cable.  etc.....  you have to get that number above 32

Also go to 08 and see if you have all the code modules downloaded, maybe your just not giving it enough time to download them all?  code modules are 08