Replacement Sky Q box Signal problems

[JVaughan]

My sky Q box non HDR 2TB disk drive failed and a replacement door stop swap was carried out. I recieved a HDR 2 TB box, as soon as it was all connected some of the channels said no signal so I stripped the cable and put some new connectors on and all was fine, this was Tuesday.
then this morning, Friday I woke to find no signal on all the channels, I rebooted it and still no signal, so I attached the cables to the tv's freesat ro see if it was the dish and all worked fine so I connected the cables back to the sky Q box and still no signal, I then swapped the 2 cables around on the box and it's started working again? Any ideas anyone?

[Chodley]

Are ALL the channels working?

[JVaughan]

When i first connected the replacement sky q box only half the channels worked, then i changed the connectors and all the channels worked, yesterday in the morning none of the channels worked, i swapped the  two cables on the back of the box and all channels worked again, I've also been getting a lot of failed no subscription on all uhd, hd and sd programmes when I start downloading more than one programme at once and they're queued this happened on the old box and the replacement box, so I'm not sure if it's the viewing card, lnb starting to fail or a faulty replacement box?

[Chodley]

LNB isn't used for downloading. Viewing card issue seems most likely.