Originally Posted by roy bates
untill someone comes along and says different,a revision 1.b doesent need timing fixes.
I don't know how many times I've said it, but I'm willing to say it again: You can't tell from the board revision if a timing fix is required or not.
Commodore (and later on Escom) have made all kinds of assembly errors on all kinds of motherboard revisions, because they just happened to have empty boards left.
Each board needs individual checking. Take photos of the relevant areas (top side: around xtal, bottom side: under Alice) and send them to the technician you trust. At this point, ACA1231 requires the same board fixes that the ACA1230 also required, so AmigaKit will surely be able to help you if you can't do the fix on your own.