Intermittant channel change problem

[HawgGuy]

New SageTV 2.2 steup. Generally works very well. By my rough estimate, channel changing works 95% of the time. Occasionally I will go to change the channel manually (or when SageTV tries to change to record a scheduled program) and the OSD will change correctly, but the channel doesn't change. If I play around a little and force it to change to another channel, it eventually will.

I using a homebrew chaintech mb with a composite input into a PVR-250 from an older Hughes DirecTV receiver. I have a standard DB9 cable from com2 (my only com port) to the low speed input of the Hughes receiver. I use a usb-uirt receiver to receive the remote signals.

It is almost as if the com port goes to sleep and while the Sage program responds to the channel change command.

Any suggestions on where to begin the debugging process? Cable, port, software tweak?

-bob