Aritech cs350 no power going to rkc pad

The dark lord

I have no power going to the remote keypad from the main panel of my Aritech cs350. I was changing out the keypad for another one but the internal sound bomb activated. I don't think i had it in maintenance mode as the arrow down button wasn't working. I disconnected the + ve fron the soundbomb to stop it. I have checked the 4 fuses and they are ok. There is 17vac from the PL1 plug so I think its ok here.I have buzzed the 4 wires from the main panel to the keypad and there is no dis. But still no power going to the keypad. I would be grateful for some further advise,

Thanks