Hi there Andygh
When you say, your speed controller is old - how old do you think the speed controller is? Have you removed the casing off the back of it? If so, did you note the number on top of the chip???
Was it ZN409CE? - if so Noah built it with the ark
or
did it have a silver strip across the top? with ED4O something on it???
Give Electronize a ring and speak to them. The chances are you may have fried the 'output' transistor but not knowing any symptoms of the POOOOOOOOOOOOOOOOF it is difficult to analyse what it may be.
it could be simple in that you may have burnt a track out underneath on the circuit board, which, if it is - you may be able to correct that yourself - or, it may be the case of what we have mentioned above.
or it may have the NWF syndrome
(NOT WORTH FIXING).
aye
john e
bluebird
i