6 volt LT at 2 amps

[pwdrive]

If you connected the secondaries in parallel the wrong way round you'd know about it soon enough

How's that?  Also if its bad then is there a way to check which goes were?

Two windings, both the same voltage output and impedance, if the windings are connected in parallel and in phase then when one end of one winding is going +ve during the AC cycle the corresponding end of the other winding will also be going +ve so current from one can't flow into the other, eg: connecting those identical voltage sources together means +ve to +ve and -ve to -ve, no current can flow from one winding into the other winding because for current to flow you need a potential difference, current can only flow from those windings if a load is connected across them, but if connected in parallel and out of phase, when one end of one winding is going +ve the end of the other winding will be going -ve so there's now a potential difference and current will flow and it will be large as there's not a lot to limit it.

EDIT: Post crossed.

Lawrence.