If you're fixing to sell:

1. Turn over the playfield and take a close look at and test the ohms of the coils. Do any need replacing? Coils can be expensive.
2. Do the same with the coils in the head, the bottom board and check the transformer. If the transformer is shot, part the game out.
3. Look carefully at the flipper assemblies, do they need a rebuild? Keep in mind that Jack in the box has 4 flippers and flipper rebuilds are pricey.
4. Look at the wiring. If this game was on location for a long time, what quick fixes were done that need ondoing?
5. Look at the exterior metal parts (legs, side rails, coin door). Are they pitted?
6. Look at the cabinet. What's the minimum you can do to make the machine look pretty enough for someone's rec room?
7. Look at the scoring reels and mechs. Are they in good shape?
8. Are any of the playfield plastics cracked? What about the pop bumpers? Do they need rebuilding, or do they work as is?

Factor in about 10 hours of work between cleaning and soldering and determine whether or not it's worth your time. Also try to remember that even at 20 cents to a dollar a part, you can still end up spending well over $100 in parts and you're not going to get much money for a wedgehead from that era. Depending on where you live, you can expect $200-600 for that game fully working.

I usually don't do any of what I suggested when initially diagnosing why a pin won't work. The first thing I look at are contact points and if there are any obvious cracked solder joints, stuck switches, stuck coil plungers, etc... I also look at the steppers to see if they are in need of a rebuild or not. I just provided a laundry list of what costs the most if they need replacing in a pin and have come across plenty of machines that are missing coils, transformers, etc. Transformers, flipper rebuild kits, cracked/missing plastics, burnt coils etc cost a lot more to replace than a coil sleeve or some rubbers and bulbs. Clear coating and making a playfield and cabinet look perfect are a complete waste of time for a machine someone's looking to get working and flip. Backglass: seal and hope it looks pretty when it lights up. Touched up backglasses are not what a rec room buyer cares about when they buy a used pin and a poorly touched up backglass looks worse than a partially flaking backglass. Polish and clean the metal parts. Add some new leg bolts to the front two legs to make it look pretty and brighter. Clean the grime off the machine. Get the game running properly so it's fun to play. That's what those types are looking for in my experience. The wedgehead era EM pinball collector who wants a perfect machine and is willing to spend top dollar represents maybe 1% of the population of people who want to own a pinball machine.