Take the hint. The pad quit working after 14 years, which is not a surprise, and I suspect the opener itself isn't too far behind it. Spend the 35-45 on a new keypad if you can find one, (I looked for about 15 minutes on the web and couldn't) and in a year or so, replace the whole opener system when IT quits working too.
Or, save the $45 and just go out and buy a new opener system now. I have used Stanley in the past and was happy with it, this time I have a Genie, and it is working really well too. Mine came with a wireless smartcode transmitter, plus two clickers. I like the screw drive better than the chain, because there is nothing to stretch out or need adjustment.