Dr. Who - Flippers trigger slings

[Vengeance]

I've got a weird problem on my Doctor Who.

Anytime a flipper coil fires it also triggers both sling shot coils as well.

It's not switch related as when I check the switches the only switches that trigger are the EOS and flipper switches in the matrix.

I've narrowed it down to the high power on the flipper coils. When in flipper test, if the flippers are triggered for hold only (low power) the slings don't fire, but any flipper coil fired with full power triggers both slings.

Not even sure where to start.

 

[necro_nemesis]

What happens when you fire the high voltage coil for the flipper with simply grounding the appropriate flipper coil lug?

Might be a bad ground or poor logic voltage supply issue. The flipper action could be enough to draw the voltage down causing the logic to fail and fire the coils. I remember something wonky about supply voltages going through the Fliptronics board. Could be a bad connector or pin header on one of those supply lines. Wouldn't hurt to re-seat connectors from the CPU as well.

 

[Vengeance]

Manually grounding the high power on the flipper coil also fires the sling.

I also have a ground issue on row 1 of the switch matrix, but I was planning to dive into that later.

It's not a board issue as I've replaced both the CPU and Driver board and the problems still hung around.

So I guess I'm having grounding issues somewhere.

I figured with the switch row I would just go through each switch and see if I could find something, what should I be looking for on the coils?

Other weird thing, if the game is left on for any length of time, the ground issue in row1 on the switch matrix corrects and self and all the switches act fine.

 

[Menace]

Do the slings work ok on their own? (do the sling switches activate the slings correctly)

This is very odd behavior, especially where you've swapped the MPU and driver, but did you try swapping the flipronics PCB too with them?

D

 

[Vengeance]

Yep slings work fine on their own, if you trigger the switches for them, they kick and release just fine.

I did not switch out the Fliptronics board, I could give that a try and see what happens.

 

[Vengeance]

It's not the fliptronics board.

Took the board out of my JM and replaced it with the board in my Dr. Who.

JM still works fine, DW still has a problem.

One question what does Connector 104 on the drive board do?

I can see that it says 50v DC, but for some reason, someone cut that connector on my machine. I know it loops back to the fliptonics board from the drive board, I'm just not sure what it does or why it was cut.

I'm going to put it back in place and find out.

 

[Vengeance]

So that explains why the connector was cut, when I have the connector 104 from the Power Driver board wired up properly to 901 connector on the fliptronic board, the sling shots lock on.

So does that make the problem worse or better?

Worse that they are locked on, but doesn't really explain anything I guess?

 

[Vengeance]

Continuing further.

So the slings use connectors 107 and 127

If I disconnect 107 but leave 127 connected, the slings still lock on.

But if I disconnect 127 and leave 107 connected they don't lock on.

So since I've ruled out the boards, there has to be some short to ground from connector 127 to the slings, I'll just have to start going over the wire to see where the issue might be, or I could try and replace it see if that fixes anything.

 

[Chris Bardon]

When you tried the other boards, did you connect up 104, and do they lock on with both boards? That's a strange one for sure, especially since before they'd trigger with the switches (without J104 connected). What about if you leave 104 connected, disconnect the coil, and test the switch-does it register correctly? Is it possible that it's something as dumb as the switch being wired NC instead of NO?

 

[Vengeance]

I just went through and made sure that everything is wired as it supposed to be, in terms of wire color and pin position on the connector.

I haven't changed a thing since I did that and now my board is burning up.

The resistors associated with those two slings are burned to a crisp and I can see a visable light come from the transistor if I turn the machine on.

If I disconnect 127 and 104 the burning stops.

If I connect 127 the burning starts again, same thing with 104, they both don't have to be connected for the components to start to fry.

Now I'm stuck till I fix those since I can't even turn the machine on without them burning up, so I'll replace the transistor and resistor and then start again I guess.

 

[Mindstorm88]

I also have a ground issue on row 1 of the switch matrix, but I was planning to dive into that later.

Suspect the opto board under the PF !!!

 

[Chris Bardon]

I'm assuming that the coils themselves test OK? Something else that I never got around to trying when I was having issues with my STTNG was to replace the problem coils with a couple of in-sequence flashlamps. That'll place a load on the circuit, but it shouldn't be enough current to blow a transistor, plus you can use that to check whether there are bad connections between the head and the board if you move wires around (i.e. does the light stay on). Sounds like a reasonable idea anyway, I just didn't have the spare sockets around to try it.

 

[Vengeance]

I haven't actually tested the coils as they seem to function fine.

I gotta replace the burnt out components on the driver board to at least get me back to the point where I was.