It's been a long time since I've had my hands on one. Was it working fine and then just dropped voltage? What's the whole back story?
There aren't many things that can go wrong;
Bad, open or burned winding? Easy enough to test with meter
Bad capacitor? Not as easy to test.
Rotating diodes? Easy enough to test but hard to get at and need to be removed from circuit to test.
Try troubleshooting guide from manual. You may be able to flash it but it probably needs a capacitor or diode(s) replaced. Again, the full story would be helpful.