MakerBot Replicator 1 Voltage Regulator Fix
What's the part number of the regulator you're putting in? The pin assignments vary from one part to another, but you can probably find them from the part number online. Some parts have the ground pin also connected to a metal part of their case. The green wire from the board should be ground (no promises!)

Assuming you've got a voltmeter, you can use it to find out which pins on the board are power and ground (easiest to do before the regulator is installed...). Then once installed, check that you're really getting 5V versus ground on the remaining (output) pin.

Since 2 of these burned out on you, I suggest taking steps to reduce the strain on the regulator. Voltage regulators turn the excess power into heat. Some things that can help:


Use heat sink grease to conduct heat from the regulator to the circuit board, the adjacent socket, etc. Hot melt glue, as the instructions you linked to mention, won't likely provide as much heat conduction.
Attach a heat sink to the regulator, or a bigger heat sink.
Get more air blowing across the regulator. You could do this by moving the regulator slightly, adding a fan, adding something to redirect some air onto the regulator, etc.
Swap in a bigger voltage regulator (that is, one rated for more current)
Turn down the voltage just a tiny bit on your power supply (if it has a control for that; many do).


Let us know how it turns out!

Steve