This power supply is a compatible replacement for Compaq part number 334540-001 power supplies. If you own a Compaq part number 334540-001 this ATX-300GU power supply will fit without modification. We also offer this power supply upgrade that will replace your Compaq part number 334540-001 power supply
: this replacement will not work unless you add this ATX to AT adapter
to your order. The power supply you are trying to replace was manufactured at a time when the industry was moving away from AT power supplies and more towards ATX power supplies. What you have is something of a hybrid from that error. Add this adapter to the power supply we are suggesting to the left, and you should be good to go.