sorry i forgot to mention (got confused with a post that asked the exact question from before) If it is posting an error code. The TSOP probaly is not bad. The XBOX will just FRAG if the TSOP was bad 99% of the time.
Also, finding a first gen is hard, but not impossible. There is one called xray3, this is the one is great on reapiring your TSOP. Best part is that is still for sale.