Frozen Picture -- Integra DTC 9.8 / SA Cable DVR

Have Integra DTC 9.8 for pre-pro.
Time Warner - Cincinnati Scientific Atlanta DVR

Periodically (1-2 times daily), after running for a while, picture freezes on TV. Sound continues. Switching inputs to Universal disk player or PS3 does not unfreeze.

Turning off Integra and restarting is only solution.

Question is what is the culprit?
Understand how squirelly cable DVRs are. Wondered if could possibly be an issue with the pre/pro. Possibly heat-induced? Integra sits on top of Classe' CA-5200 in cabinet with back off and am leaving the front door open as well until I get active ventilation installed.

Any thoughts?

Try direct wire from DVR cable to monitor, bypass the pre and see if it happens but if it was cable box you would have to reboot it talking several minutes (hold power button in till cable box goes into boot cycle)
Will have to try it out and see what I can see. Am with you on the cable box not having to be reset, thus the finger possibly poitning at the pre/pro.