JeffB wrote:There are other ways to remagnetize a dead magnet without removing it (...)
Hello,
None of the methods tried by me have worked with these magnets. But the heating to soften the glue has worked well in order to remove the old magnets. As they fit perfectly, without gap, I previously had to make two small holes on the sides of the magnet (at 180 degrees), in order to pull them out with a thin pair of pliers, since the glue softens but it is not enough: I first tried pulling with a powerful neodymium magnet, but these old ferrite magnets are worse than a piece of iron.
The optimal diameter is 1/2" (slightly less than 13 mm), but since I didn't find the optimal height (4 mm) with that diameter, I finally bought these:
https://www.ebay.com/itm/182192631433 (12 x 4 mm)
They have the power threshold, because they activate the sensors perfectly, but the pieces repel each other a bit. If the pieces are in the center of their squares, there is no problem. But while playing, if you place one piece too close to an adjacent one, you notice how it moves slightly.
After sticking a new felt, the pieces are perfect again.
Best regards,
Berger