Have you run them above 1500-2000rpm? They don't start generating at all at low rpm like alternators. Do a couple of higher power runs and see if they come online. Otherwise, there are also two boxes (If forget what they're called), one for each gen, in front nose compartment that somehow regulate the voltage, and they can be fried. Morris is your best bet when it comes to sourcing these. Third option is that they simply need overhaul and have bad carbon connectors in them. Not very expensive to do and should probably be done in any case if they've not been done for awhile.
