This is incorrect, Q53 (2N5401) is a PNP transistor, it requires a low on its base to turn on.

Yes, a high output of the 47LS274 is normal for all de-energized coils.

The following diagram is drawn in an energized state with green highlights representing low signals, and red representing high signal levels. Also keep in mind that regardless of any circuit operation, if you have a path to ground at pin 4 of J129, your coil will energize.
PDB Driver (resized).png

Sparky,

While probing around on this board its always a good idea to have your high voltage removed; you should be able to accomplish this by leaving your coin door open.

The best way to check the collector on Darlington transistors (TIP102) is you check the metal tab; the metal tab on this type of transistor package is always tied to the center leg, which in this case if the collector. Don't be surprised if you have no voltage here since a previous post indicated your have the coil disconnected, having this disconnected will remove the +50V from the transistor as this voltage comes from the coil, not the PDB.

I just realized that you purchased this game with this problem. Please do me a favor and remove J127 and leave it disconnected for the remainder of your tests. Also verify there is no connector on J129, as it's unused in your game. I'm asking you to do this as I don't trust the playfield wiring since this problem existed at the time of purchase.

Re-check the same items Grumpy had you test, if you still have a bad reading on the TIP102 then replace it.

I personally never do this, but I understand the reasoning behind it, especially on an unknown machine as you have no idea what a previous tech did to this game, and the cost is definitely not prohibitive. If your confident in your soldering abilities then I say go for it.

Other thoughts...

Your new transistor should not have blown this fast so what could have caused it to blow?

1)

This can happen if the thru hole or trace was damaged when removing the TIP102 as this would break the connection the flyback diode. Without the flyback diode an excessively high voltage will be applied to the drive transistor when it turns off; this will destroy the transistor, the number of hits it can survive depends on the transistor.

Testing procedure ... perform a resistance check between the metal tab on the transistor and the anode side of the flyback diode. Note, the anode is the side WITHOUT the stripe.

2) Installing a coil with a diode and hooking up the wires incorrectly, performing this action will usually blow your fuse, destroy both the coil diode and the drive transistor due to excessive current flow. Under these circumstances your coil should not fire unless the diode burns open removing it from the equation; however this is not the normal fail mode for rectifier diodes.

3) Your flyback diode (D22) was replaced backwards. This instance would result in the same conditions as listed in number 2.

That's exactly what you should have, so you know it its making good contact.

That huge, and it does mean a lot, sounds like you found a gem with a relatively minor issue.

Usually intermittent problems are connection problems, possibly related to data lines. The thing I don't like is that you are only seeing an issue with one solenoid; while its unlikely, you can have an intermittent problem with the Sol3 clock signal from the MPU; a quick and easy way to rule this out would be to flip over your ribbon cable between the MPU and PDB, this would place the current Sol3 clock wire on an unused pin. If this or data line 4 had an issue, you really should see this across multiple coils though

There is a testing procedure where you can substitute a 12V Lamp for your coil and use the TIP102 to activate it, but it can be a little dangerous if not done properly.
I know how to do it, but I believe Zaza made a nice graphic of how to do it, if your interested I can see if I can find it.

This will work fine.

The following information is provided for information only and not recommended for a single board repair.

Pro tip:
My main goal on every repair is for the board to look like it was never repaired.

For this type work I use a high speed drill with a ball mill to grind out the damaged area. I will typically fill the ground area with epoxy http://www.circuitrework.com/features/627.html there are dyes available to add to the epoxy in order to match it with the PCB color http://www.circuitmedic.com/products/115-1322.shtml. When grinding out an area next to a pad/trace like yours, I will usually pre-drill the pad for a replacement eyelet, then heat and lift the pad out of the way before grinding in order to avoid damaging this connection point...the broken thru-hole will be fixed in the next step.

The best fix (permanent) is to install circuit board eyelets of the appropriate size, this involves drilling a slightly larger hole through the board in order to accommodate the eyelet. If a run is involved with an intact pad, you install the eyelet thru this connection point and pre-solder these points to ensure a solid connection before installing your component; this involves filling the hole AND flowing the connection between the pad and trace.

NOTE: most people will not have any of the materials mentioned here to do this type of work; the cost of obtaining these items is very high and not cost effective for repairing a single board.

it's not, I like to provide additional information as you never know who all will come across this thread. The links are additional information on how to repair scorched boards and the products available to perform the repair. But again, none of this is directed at repairing a single board.

I'm not surprised as unfortunately this type of work is no longer mainstream

Here is a link to the board repair kits, you will need to pick out the one(s) that best fit the type of repair you are performing.
https://www.all-spec.com/Catalog/Soldering-Rework/PCB-Board-Assembly-and-Repair/Circuit-Board-Assembly-Repair-Kits

Doesn't look like the bridges were easy either