Since it just started and the fuses are fine, start simple. Reseat the Jones plugs. They are the connectors that are between the cabinet and the head. A little corrosion could make them work intermittently. Then, check to insure the Jones plugs are visually connected (each pin) and no wires broken.

Did you pull the fuses out to check them? If not, do so and check for continuity. May look good by eye, but not when 'buzzed' out.

Make sure the fuse holders are not cracked. You'll notice the fuses are fed with 1 maroon/white wire on one side of the fuses and leaves the fuses as 2 separate wires. 1 for the playfield, 1 for the back box ,both via the
LOCK RELAY which I think is the second relay from the coin door on the bottom. The colors FROM the fuse holder to the lock relay vary, could be blue/red, blue/white, blue/red etc., but you should see these connected (thru contacts on the lock relay)
to a solid Blue for the playfield, and a blue/white for the backbox, down on the lock relay. Check for good connections on this relay, clean and or bend contacts as needed. If that's not it, you can follow the blue/white wire from the lock relay thru the jones plugs to the backbox to see if you can find where your loosing power.

Glad to hear you got the light back working.

Just got the same machine.. having trouble with start up.... relay switch contacts may not be set right.
Anyone have a good functioning machine and willing to take pictures under the hood?
Does anyone have or can upload pictures of all relay switches so I can duplicate and hopefully get a proper start up/game ready?