Congratulations on the baby!
Regarding the Digitcube, i does not have MPEG4 decoder, as already mentioned.
You need to try with an MPEG2 broadcast, typically using DVB-S, DVB-T or DVB-C. All DVB-S2 transponders I am aware of, use MPEG4. Also, some DVB-T transponders (like here in Portugal) use MPEG4.
A field meter with only MPEG2 is partially obsolete, because less and less transponders use MPEG2. It is not totally obsolete if it has DVB-S/S2/T/C capable tuners, because you can still perform useful measurements.
Don't bother to open your meter. You won't find anything repairable. Even if you had equipment to desolder/solder SMD, you would have a hard time finding the required components.
Only if MPEG2 is not working, too, you could consider a bad contact or lose cable inside, but I doubt that. Rover Instruments meters are very well built.