1.4 athlon thunderbird in k7vta-b

I've had a 1.2 Athlon in my K7VTA-B for years. I came across a 1.4 and
haven't been able to get it to work in the K7VTA-B. I know the CPU is good
because it works in another motherboard. I have the latest bios (K7VTA-B
_2BA1). No luck setting the multiplier to auto or manual. The manual dip
switch settings (per the manual) only go up to 12.5, so I figured with the
latest bios that with a 1.4, you'd have to have it set to auto. Anyway, no
matter what I've tried, when I turn the computer on, I get the bios voice
announcement that the cpu may be bad. Tried clearing cmos in between
changes and that hasn't helped either. The Soyo web site says that the max
cpu in the K7VTA-B is a 1.4 Thunderbird, so I suppose in theory it's
supported. Just wondering if anyone has had success getting a 1.4
Thunderbird working in a K7VTA-B, and if so what motherboard settings were
used. Thanks.

Steve