|Since you have the 3000+ out of the board, look at the model number. Is it AXDA3000DKV4E or AXDA3000DKV4D?|
I assume you have the manual for the DIP switch settings?
133MHz = 1-off, 2-on, 3-off, 4-on, 5-off
166MHz = 1-off, 2-on, 3-on, 4-on, 5-on
And each time you remove the heatsink, you should be throughly cleaning it & using a fresh dab of paste on the CPU core. The size of a grain of rice, spread thinly & evenly is all it takes. And make sure you don't mount the heatsink backwards.