Please contact technical support directly (reply to your order confirmation message or use our e-mail or contact form) so that we can send you a replacement transistor. Make sure that there isn’t damage to the circuit board around the location of that transistor.
If you’ve already removed the offending transistor, it should still allow the other four digits to light, so there may be something else wrong. Double check the instructions: Make sure that you’ve got all the parts installed, that they’re in the right places, in the correct orientations, make sure that your chips are fully seated in their sockets.
If you continue to have difficulty, you might consider sending us clear photos of the top and bottom of the circuit board (again, by e-mail — it’s much easier to share photos). We can often identify issues that way. If all else fails, there are some alternative debug strategies including physically sending the board to us for diagnosis or repair.
