If it's got a silicone rubber keypad, you can bet your bottom dollar that's what's knackered, they must be the most unreliable, short lived component in the whole of the electronics industry. My Humax handset's knackered already and it's only a couple of years old, but it has a visible LED as well as the I/R one, so you can easily see when the buttons are playing up.
I have the same problem with
MY Humax remote control!
It started off with the TV button (middle of top row; makes the remote control the TV) then the STB button went (left of top row; makes the remote control the Humax box), finally the On/off button itself stopped working (right of top row).
I think the PCB under the buttons flexes and eventually cracks some tracks, but I haven't taken the control to pieces to check.
I bought one of those lookalike remotes on
ebay but discovered that it is only about 95% compatible! Some buttons are in a different position, but a couple of them don't exist -
Recordings and
List, both of which I use a lot.
So it was back to the faulty control and some workarounds - I discovered that if you press any of the buttons labelled 0/1/2/3/4/5/6/7/8/9 that turns the Humax box on, that turns the TV on, and that turns the soundbar on! I have the system set up so the Humax box and soundbar are turned off when the TV turns off. It means I need to keep 2 remotes handy now rather than just 1.
Actually 3 controls - I turn the soundbar off at night and use headphones instead in case my neighbours or guests could hear my TV on until 3-4 a.m.!