Weird playback issue with DVR system (black screens)

[n0fx 0]

I have a Channel Vision model # DVR-8N DVR unit. I've had this unit for a few years and it's been working fine but recently I've been getting black video on some of the channels during playback. I thought it was an issue with the hard drive, so I replaced it with a brand new one but it didn't do anything. I tried to just view the individual channel to see if it was a problem with the system playing back too many channels simultaneously but that didn't help.

 

The unit is only about 3 years old and I don't know what else could be causing the problem. The channel looks fine with it's streaming live video but only when it's playing back that I have issues with it.

 

Does anyone know what else could be wrong with the unit?

 

Thanks.