My Shadow developed an issue awhile back. The wife and daughter were playing it and I was told it "smoked" from the left side of the PF. I shut it off pulled the PF up, saw nothing but smelled burnt electrical smell. Lifted the mini PF and saw the rear target bank coil (solenoid 24) was toast.
I began checking it out and did the following first:

-replaced the coil
-replaced the blown fuse - f103

Yes I should have checked the drive transistor but I had the coil and fuse on hand and my DMM was at work. I started the game up and the coil of course started to burn up again. I shut if off ASAP. I then:

-replaced the driver transistor - q32
- i don't think the fuse blew this time, but it might have and if so was replaced.
- did not replace the coil, it ohmed around 7.2-ish which is what the other 25-1000 near it ohms to

Started game up and watched the coil, it didn't appear to be getting hot. Next thing I know, smoke is coming from the Q32 transistor area and it was burning up. It got so hot it melted the solder and almost fell out of the through holes of the board. It was shorted ground leg to middle leg again and had physically burned the three components above it, r49, r48 and q31.

I then replaced :

- q31
- q32
- r48
- r49
- q32
- and r46 and r47 because I figured what the hell, the heat was moving upward

Start the game up and the same thing begins to happen. I can see the solder start to melt on the right side ground leg. I shut the game off and the transistor was again shorted outer leg to middle. I removed the board and replaced:

- q32
- D11... As I see it this diode is in line with q32 and I guess has to do with the tieback diode stuff. It tested good but I figured what the hell at this point.
- Disconnected the grounding wire at the coil, wanted to see what would happen in this scenario since this is the circuit in question.

Stated the game up and nothing abnormal happened. Of course the coil doesn't work but it ran for awhile and the q32 wasn't hot at all. I then re-soldered the blue wire back to the coil, started the game up and before I could shut it off it shorted the transistor again (did not blow the fuse).

Could the coil be bad and causing this since it was originally installed with a shorted transistor and DID get hot? It still ohms 7.2-ish like another 25-1000 coil I checked. Could the 74ls374 chip that is in circuit ahead of these components I replaced cause this? As far as I can tell I've replace everything else in this circuit, unless I'm missing something.

Yes the coil locks on AS SOON AS THE MACHINE IS SWITCHED ON, even before the other coils pop as in normal start up mode.

I don't have anymore transistors to replace q32 until I place an order and receive some. Therefore I can't test the two scenarios you propose yet. I should have thought of pulling the coil wire prior to shorting my last transistor I had on hand.

There is no diode across the lugs on this coil.

The coil is a ae-25-1000.

I did reseat the j122 jumper wire, that had no affect on the issue.

I thought D11 was the diode that the coil is connected to. Am I incorrect on that? If so that might be my problem. I take a look tonight if I get time.

UPDATE....
The transistor actually did not short out the laST time I powered it up. I must have shut it off in time to save it. What fooled me is....... with the machine powered off, if I connect both wires to the coil, the q32 transistor shorts out and test bad on the board. If I remove one of the wires on the coil, the transistor is no longer shorted. What would cause that, because that is obviously what's happening that is shorting out and heating up the transistor.

The new coil, just like the old one, did not have a diode on it.

The D11 diode I installed is installed correctly. I made sure of it

I wanted to clarify the current issue I described in Post Number 6. When both wires are connected to the coil, there is continuity between the Middle leg of the Q32 transistor and the outer leg, which normally has continuity with ground. If I remove either of the wires from the coil the Q32 transistor no longer has continuity between those two legs and beep tests normal.

BACK FROM THE DEAD!!!

I't been a long time since I started this thread and I just got around to checking back into this issue TODAY.

Fattdirk - I ran another wire from the J126-8 connector to the coil lug (thus eliminating that wire from the equation. The short is still present, and by short I am referring to the conditions I mention in POST NUMBER. So that wire is not shorted.

I decided to beep test the J126-8 connector with ground. It does NOT beep to indicate continuity with ground. BUT, when I ohm test it with ground, it ohms 74 ohms. I checked all the other pins on the J126 connector and they test out to megohms. The transistor is not shorted, all this testing was done with the game unplugged. This would make me think there is still a problem on the driver board.

Any other suggestions or things you see that I've missed? I've kinda run out of spare time to be pulling the board and checking this and that on it. I'm fine with putting a rotten dog board in it, but I don't want to have mis diagnosed it and ruin a new Rottendog board.