No POST with mulitple change A7N8X-X

Board: A7N8X-X
CPU: Thoroughbred XP2000+
RAM: Crucial PC2700

The board automatically unlocks the multiples under 12.5, but if I change the multiple to anything other than 12.5, I get no POST at all, not even a beep.

I have an A7N8X I run a 2500+ Barton on at various multipliers without a problem, and a 400 (200x2)FSB.

Even with a 266 (133x2) FSB the 2000+ won't post if I change the multiple.

I read about the pin shorting technique, but isn't that what the mobo is doing already?

2A

I've read that you may have to set a jumper to have that board work right for unlocking, but I don't know any more than that. You might check that you have latest bios as well