From InterceptRadio.com Wiki
AOR AR3000 repair information & notes
Most AOR AR3000 and AR3000A radios are now getting to the point where parts are failing due to age.
The most noticeable failure are the keypad buttons needing to be pressed hard to work or not working at all.
You can replace the buttons but be forewarned that it is VERY easy to accidentally lift the PC board traces when removing the buttons. Be careful !!
After a lot of looking I found a replacement button which fits & works:
My AR3000 has 22 of these buttons. Order 25 of them so you will have a few spares if needed.