Abacus: It's my understanding that Yamaha only recommends "ECC" type PC133 dimm memory, as evidenced in their Tyros2 DIMM chip compatibility list. The Kingston memory chip you linked to is unfortunately,
"Non-ECC" type memory Kingston's designation for their "ECC" memory is X72, and for their "non-ECC" memory is X64:
KVR133
X72C3/512 ECC Memory
KVR133
X64C3/512 Non-ECC Memory
Here's where I purchased my Kingston KVR133
X72C3/512 DIMM chips ($81/each):
MWAVE ,
and which I have successfully installed in my Tyros2 keyboard.

ECC:
error correction code Scott
[This message has been edited by Scottyee (edited 11-06-2005).]