Any suggestions to help me fix my latest problems,

It all started yesterday while playing the Shadow with no errors.

1ST, the drop down wall target didn't return up (or down I cant remeber), upon investigation the wall target has snapped at the very bottom causing it to wedge in its either up or down position, I may try and fix or get a new one.

While I saw this I noticed diode across switch on this assembly was loose and i soldered it in place.

2ND, upon power up I now get 3 nasty messages,

GND SHORT ROW 1
CHECK SWITCH 51 WALL TARGET DOWN
ER. WALL TGT. BAD CHK SWITCH/COIL

3RD, so now I have no switches in row 1 operational.

In test solonoid mode the wall target will go up and down no problems, also I can't test the switch as it is row 1. I assume the coils on assembly are fine as they are working in tests.

Is it possible a broken diode can take out a whole row?

Any hints or clues to speed up my fault finding.

Hi, thanks for your suggestions, I've had no luck fixing it yet.

Here's what I checked out so far, no transistor faults found on the driver board.

The sanctum wall drop down target assembly all checks out I think, both coils, switch and diode both fine too.

Playfield and cabinet switches and wiring looked over to see if anything is touching something it shouldn't.

Each switch on the Row 1 looked over, I have yet to check these diodes.

I pulled off connectors J107 + J109 and the display was still telling me I have a ground short row 1 as well as the other original faults, was that the correct way to check if the problem is circuit board or playfield?

Back to more research.

Clutching at straws here,

Does anyone know if there should be a diode across the larger coil on the sanctum wall target assembly??

Yep, I've just been reading on cpu board chips, I'm gonna look at U20, then U18 and U19, hopefully I have some of these chips in a drawer. Also I'm gonna check out the under playfield opto board as well.

So if a coil didn't originally have a diode across the lugs and I put one on, could this do any damage?

Today little progress, the santum wall assembly is back under the playfield and my attempt to fix the drop target has worked, I used JB weld.

I also lucked out and have chips to replace the suspected faulty ones.

I changed U20 and no change, however one of the error messages has now gone(CHECK SWITCH 51 WALL TARGET DOWN)

I think this was due to the santum wall assembly being put back.

The real issue is still to be found and I'll give it another bash tomorrow.

Do you know if it's possible to have faulty LM339 at U18,U19 while the ULN2803 at U20 is all good?

Hi all, I appreciate your time, patience, help and advice. It is helping me as there is a lot of info to digest and understand.

Well I put the game into switch test 1 and THEN removed the connectors on cpu, previously I had been removing the connectors first and then trying stuff and having no luck.

Once it was all unplugged the row 1 ground short vanished + others, which hopefully means the problem is on the playfield or cab and not on the circuit boards, then plugged them back in.

I disconnected every under playfield connector one at a time to look any changes in the switch test, when connector J3 was removed from the "10 opto switch pcb" A-18159-1,
the Row 1 ground short disappeared, then I tested all switches on the playfield and got a good result, ALL switches are working except for the opto's.

Unfortunately there are two opto switches on Row 1, one of the opto's is on a ramp, the other is in the ball trough, so I havn't discovered the real problem only narrowed it down I think. I had a brief look at the board and two opto's and cant see any obvious fault, so it's back to reading up again.

A couple of questions to see me on to the next stage,

Do you think i'm on the right track?

Can damaged opto parts such as infra red diode/ infra red photo transistor cause row shorts?

Do you think the problem is on the opto board?, it has three LM339's on there and diodes too.

Is there a way to test opto's? in this situation.

Thanks.

Good news...

After replacing the three LM339 chips on the opto switch board the "ground short row 1" is fixed.

Wow this was a hard fix for me, and I probably took the long route to discover the problem. I don't know if all three chips were broken, but at least one was.

The drop target I fixed broke again, same place, so I will need to deal with this. Also one error message saying "ER. WALL TGT. BAD CHK SWITCH/COIL", but I'm not to worried, I think this message will go away when the drop target works in conjuntion with the drop solonoid. Both solonoids and switch all work independently, it just needs to be properly tested and with the broken target I cant at the mo.

Thanks guys and merry christmas.

Completely fixed now,

That JB weld is great stuff, but not for fixing a crack in the bottom of the sanctum wall drop target. I have used an alternative fix for now and it's holding up v.well.

While the glass was off and was giving this target mech a good workout, I played(cheated) my way to the wizard mode, how cool is this game. It's very hard and I can't wait to do it for real. Does anybody else like to take the glass off their machines to play just to see all that the game has to offer??