JP1 Remotes

I got it in 2011, warranty expired in 2012.
I'm unable to do ch+ and ch- from 6131n nor from the OEM remote.
There are buttons on the back side. Difficult to get to because it stands in the corner behind the kitchen sink.
Anyway, those buttons do not work channels up/down either. Except as up/down when I select TV menu.
It broke recently, sometime last week in a strange way: at first 6131n failed but OEM remote worked. A day or two later the OEM remote signals failed as well.

I looked in the manual hoping to find something about a reset button, but nothing there.
Is there anything I can do to fix that?

Is it only the up/down that don't work? If all your channels got erased from memory, then there is nothing that up/down can change to = rescan

Reset is normally a menu function on this brand. Some models report a tiny hole between two rear connectors hiding a button.

Thank you very, very much
You're correct. I missed that there is System Reset. It's on the HELP menu of all the places.
I don't know if it did anything. It lasted a second.
I did not have to rescan. The channel list was still there but all stations were unchecked.
Once I checked them, ch+ ch- work from the TV buttons and both remotes. Wheew!