The problem with the blown fuse / #7 coil has been resolved. For anyone with a similar problem, here are the steps I took to resolve the problem (see images for more):
1) With the machine powered down and the power source removed (unplugged from the wall) for a while, remove I/O Driver board from head, paying attention to where the wire harnesses, etc. were attached (take pictures!). Note: Try not to touch any of the connections on the PCB before draining the capacitors.
2) Drain the main / high voltage capacitors (nine "large" on my board, with scores of small capacitors that were less of a concern) on the board using an *insulated* resistor (the resistor I used was, by the calculations, not rated high enough for the expected wattage, but it still worked. Note: just shorting the capacitor using a screwdriver is NOT recommended by professionals, despite the fact that the advice to use a screwdriver (etc.) is often given by people working on boards).
3) Locate, desolder (using a "solder sucker" like I did (or braided wire, which I did not try)), and remove the suspect component. In my case, it was a MOSFET transistor, labeled Q7 (the transistor corresponding to the coil that was blowing the fuse) for the WhiteStar board (see screenshots of the manual for NASCAR I posted above to help locate the problematic transistor).
4) Test the transistor *out of circuit* (completely removed from the board). There are several YouTube videos on how to test a transistor using a digital multi-meter (DMM), but note that DMM's may not be the best way to test the transistor (several videos suggest constructing your own transistor tester, which was out of my wheelhouse, but not too difficult). In my case, the Drain to Source on the removed MOSFET transistor (Q7) was conducting a relatively low resistance amount of electricity even after it was discharged (this is the "easy" problem). This indicates a bad transistor (see videos). However, DMM's vary in how much voltage they can put across a component, so not all DMM's are suitable for all transistor tests. That is, my Velleman DMM did not seem to have enough juice to turn the transistor "on" in a way that I could test the old or new transistors by turning them on (Gate positive, Source negative) and then looking for issues with the drain rate (Drain positive, Source negative, until "empty"). However, I still was able to use my DMM to test the suspect transistor, so give it a try with what you have once you understand the way MOSFETs work.
5) Find a replacement transistor. I ordered my STP22NE10L (a IRL540N MOSFET transistor, I think) from Marco's for $2.99 + shipping. Marco's specifically listed this transistor as a "Q1-Q16" replacement, so I was confident that I ordered the correct part because I was replacing the Q7 transistor. However, I had trouble confirming the part was the correct replacement by using the Stern manual / Stern forums - it seems that I lucked out with the description Marco's gave for the part. The transistors typically (but not always) have part numbers printed on them. Make sure that you replace the component with a compatible part - otherwise, you could destroy your Driver board, damage your machine, etc.
6) When the new part arrives, test it the same way you tested the old one. In my case, the new transistor did not conduct electricity between the Source and the Drain, but the old removed transistor did. This was good news for me; something should function differently between your old part and the new one if you are hoping to solve a problem with the new part.
7) Insert the new part into the board in the correct orientation (again, make sure you take pictures and understand the Gate, Drain, and Source order of the transistor).
Gently pull the leads apart so that the part stays in the board while you solder it.
9) Put some flux on the leads and the "holes" on the board.
10) Use your soldering iron - CAREFULLY - to heat the lead and PCB hole to the temp that it will melt the solder (Note: do NOT use acid-core (plumber's solder), use rosin core tin / lead mix solder). This is tricky - the temptation to apply the solder directly to the soldering iron is immense when using a cheap iron. However, this can lead to cold joints / bad solders, so don't do it. The part and the board could get very hot in the process - this is just how it works if you don't have a temp-controlled iron. Apply a small amount of solder and connect the part to the board (there are tons of YouTube vids that show how to properly solder on a PCB).
11) Make sure you have good solder joints (by visual inspection, and make sure that your solder isn't making connections across joints) and clip off the leads of your transistor so they are no longer than the clipped leads from original production.
12) Reinstall the board in the head and, with fingers crossed, fire up the machine. In my case, replacing the suspect transistor solved the problem.
I have never worked with PCBs or electronics soldering (I've soldered some EM parts, but never PCB components). I did about three hours worth of research and the whole process took less than 30 minutes to complete. YouTube is exceptionally helpful, as is the advice on Pinside (thanks 
GRUMPY !). I bought this machine from someone who said it was "hopeless", but, after 3 hours of research and 30 minutes of labor, and a $3 part, I was able to take an unplayable machine and make it into a machine that was 90% operational (still some switch issues, but nothing too major, I hope). If you feel overwhelmed or confused, just remember that all mechanical / electronic things can fail, and all mechanical / electronic things can be fixed.
20170523_002539 (resized).jpg
20170523_010201 (resized).jpg
20170523_010627 (resized).jpg
20170523_020903 (resized).jpg
20170523_021551 (resized).jpg
20170526_013508 (resized).jpg
20170527_142129 (resized).jpg
20170527_142149 (resized).jpg
20170527_142318 (resized).jpg
20170527_142439 (resized).jpg
20170527_142445 (resized).jpg
20170527_143036 (resized).jpg
20170527_143039 (resized).jpg
20170527_143454 (resized).jpg
20170527_161745 (resized).jpg
Louisville, KY
