Chanel listings go missing on weakly basis, also......

Hi,

This has been an ever increasing problem that is picking up steam lately.  I know it is a pretty old receiver.

Problems:

1) All chanels on the chanel listing go missing, there is no shows displayed.

2) Sometimes I can't go above any chanels above 200.

Receiver Information:

Back of receiver it says Thompson, Inc.

Model Number: DRD435RH

Solution to both problems:

I have to unplug the box, let it sit for a minute and then plug it back in. The box then downloads chanel information and then things work again.

Thanks in advance for any advice.