A long time ago, a batch of boards went out with one tiny component missing off the circuit. We didn't realise it at the time, but on rare occasions it can cause your Bangalore to mis-fire.
To check your Bangalore's circuit board, first remove it from the control box. See "Removing and Fitting Your Bangalore Broadside Circuit Board" for details on how to remove the circuit board from the control box.
Once you've removed the circuit board, look on the rear at the components. At the top-left corner, about 3cm in from the edge of the board itself, you should see printed on the circuit board "C1" (it's quite small, so look carefully).
Just to the right of this should be the C1 capacitor - looks like a small, brown, rectangular component:
If all you see is a blob of solder, your C1 capacitor is missing:
If your C1 is missing, we'll have to have the board back so that we can fix it.