This week I was lucky to find 2 pairs of Celestion 5 for a price of $30 for both, locally through Craigslist, both have the tweeters in very good shape. I used one pair of tweeters to replace the F-series currently installed in my A2. The other pair, I use it in another room and also keep it as a backup just in case.
Thanks to info from this forum, in deed the tweeters are identical, except that the A2 tweeter has a Faraday ring that the C5 does not. Other than that, they are the same.
Just remove the diaphragm from the C5 and re-use the magnet from the A2. The speakers now sound sensational like before, which is far better than the cheap F-series tweeter that I temporarily installed earlier on.
This is what I did to remove the diaphgram. First I removed the 3 inner cricle screws to allow me to detach (lift off) the magnet, but still keep the housing on the diaphgam, then I used a hairdryver and turn it on to high, then blow it on the housing side surrounding the diaphragm, but not on the coil, just do it for about 10 seconds, not longer just to be sure not to overheat it, the heat caused the glue to melt and allow me to easily peel off the diaphgram from the housing.
After that, it is just a simple task to mount it back on the A2 and reused the magnet of the A2 that has the Faraday ring.
Before starting, be very careful to mark which side the positive is. Also the magnet is extremely strong, it can suck up the screws and metal pieces, so keep those far away. Also try to blow off the dirt during the work to keep the diaphram clean.
Voila, a good pair of A2 speakers again.