Only one tuner working - sometimes it's A and sometimes it's B

[jet2ride]

Hi
I've had this solo2 for around 18 months and all has been fine
until recently. It's now started to only receive on one tuner.
If I go into sat finder then A will be working fine and B not.
If I reboot the box then both tuners work for around 10 seconds
And then one will stop. If in sat finder I'm looking at B then A will stop
and if I'm looking at A then B will stop.
If A is working, I can swap the leads over and A still works.
I replaced the LNB with no effect.
Both tuners are set in simple mode to 28.2E
I've done plenty of searching and reading but can't find anything on this.
Doin my head in this..........
Any help advise appreciated
Best regards
H..

[jet2ride]

Sorted now.
I forgot to mention I had tried other images and my back-ups with no effect.
I used the download feature to install the new ones.
When I installed a new image from the front usb the fault cleared and all is working now.
Cheers
H..