1. I have a non-flip two-button Hella key number 730 955-00 433 MHZ 5FA 007 680. Will a Siemens, or any other make of key with the same or different number work? If so, how do I find out what they are?
2. Some key numbers start the same but have different last number/letter groups. Are any of these compatible?
3. I have read that there is no difference between 433MHZ and 434MHZ keys – they are all 433.92 either rounded up or down. Is that right?
5. There are plenty of instructions on how to remove badges and extract the small cylindrical transponder for replacement … but mine has neither badge nor transponder (so far as I can find) just a printed circuit board (PCB).
Here you can see the location of transponder chip.
Both 433MHz & 434MHz operate at the same 433.92MHz - 434.42MHz frequency, so it does not really matter.
Any fob should work as long as it matches the frequency range, in your case 433MHz or 434MHz.
You can use atleast following part numbers: 1J0959753CT, 1J0959753N and 1J0959753AG.
These are two button fobs, but you can also use three button versions as long as the frequency matches.