Data East Monday Night Football solenoid constantly firing upon powering up the machine

[HamfistedSolderTroll]

Recently, while messing around with the mechanical switches connected to the flipper solenoids, I caused a short. I saw a brief spark and immediately one of the ball launcher solenoids began firing. If you're familiar with the game, after you initially launch the ball, aiming for the 10, 20,30, or 40 yard holes, the ball drops down and then is fired out onto the playing field. It's that solenoid that fires it out that is constantly firing, anytime the machine is powered up.

According to the documentation I'm looking at (https://www.ipdb.org/files/1616/Data_East_1989_Monday_Night_Football_English_Manual.pdf) , it's part number 8 in the attached drawing.

I'm pretty handy with a volt-meter, but I'm not sure how go about finding what's shorted, or where to start.

I noticed there is a small control solenoid on the PPB that also clicks each time the main solenoid fires. I'm not sure if that helps to determine the source of the problem, but I'm trying to provide as much information as I can.

Can anyone get me pointed in the right direction?

Thanks in advance for any and all help!

 

[Moonraker]

I had a project DE Robocop that had a continual VUK firing - it was caused by a trough switch no registering so the game was trying to restore the missing ball to the trough. Yours might be trying to do the same.

I would disconnect the solenoid that is firing and then put the game in switch test and check that all the trough switches can be activated.

 

[Ashbo]

I helped a friend with a data east time machine once where his EOS switch had failed and arced. It turned out it had caused one of the transistors in the backbox to fail (Q54)

Sounds familiar with your situation, but check what @Moonraker said first.

 

[Ashbo]

I helped a friend with a data east time machine once where his EOS switch had failed and arced. It turned out it had caused one of the transistors in the backbox to fail (Q54)

Sounds familiar with your situation, but check what @Moonraker said first.

And just a note, try to avoid working on a pinball when the power is on. Accidents do happen and invariably cause damage. ...we have all been there.

 

[HamfistedSolderTroll]

I had a project DE Robocop that had a continual VUK firing - it was caused by a trough switch no registering so the game was trying to restore the missing ball to the trough. Yours might be trying to do the same.

I would disconnect the solenoid that is firing and then put the game in switch test and check that all the trough switches can be activated.

I'll check that next time I'm out there, but when I was there last I pulled the wires off of the switch that activates that launcher solenoid, and the solenoid continued to fire, so I don't think it's a bad switch. Again though, I will check that next time I'm out there.

 

[HamfistedSolderTroll]

And just a note, try to avoid working on a pinball when the power is on. Accidents do happen and invariably cause damage. ...we have all been there.

Yeah, I have occasional flashes of idiocy and this was one of 'em. "I'll be really careful, just want to see if that switch is making contact..."

 

[Moonraker]

It does sound like you've blown something on the PPB or MPU and trough switches won't be the cause but it is worth checking before pulling the game apart as it's a easy thing to check and a problem with trough switch would give you the symptoms you have described. If you've blown the switch matrix then doing this switch test will confirm it.

I'll check that next time I'm out there, but when I was there last I pulled the wires off of the switch that activates that launcher solenoid, and the solenoid continued to fire, so I don't think it's a bad switch. Again though, I will check that next time I'm out there.

You've mis-understood which wire to take off - it's one of the ones for the solenoid that is firing (just to stop the firing whilst fault finding) and not the wire for a switch. You will need a soldering iron to remove it, do NOT cut the wire to the solenoid. Then put the game in switch test - do you know how to access the switch test? The how to is on page 19 of the manual. Remove all three balls from the trough then test the switches by pushing a ball in to the trough from the trough drain, it should roll in to position in the trough and switches 13 (trough 3), 12 (trough 2) and 11 (trough 1) should activate with trough 11 being retained on the display. Then repeat for the second ball (switches 13 (trough 3), 12 (trough 2) should activate with trough 12 being retained on the display) and then the third ball now only switch 13 (trough 3) should show on the display.

 

[Pick Holder]

Does it fire up when you turn the game on or does it fire, then stop, then fire, then stop as if a ball is jammed?

 

[HamfistedSolderTroll]

Does it fire up when you turn the game on or does it fire, then stop, then fire, then stop as if a ball is jammed?

Good question. When the machine is powered up it begins it's self test procedure as per usual. When the solenoid in question is dormant until it's triggered to fire, at which point it continues to fire over and over until power is removed.

 

[HamfistedSolderTroll]

It does sound like you've blown something on the PPB or MPU and trough switches won't be the cause but it is worth checking before pulling the game apart as it's a easy thing to check and a problem with trough switch would give you the symptoms you have described. If you've blown the switch matrix then doing this switch test will confirm it.



You've mis-understood which wire to take off - it's one of the ones for the solenoid that is firing (just to stop the firing whilst fault finding) and not the wire for a switch. You will need a soldering iron to remove it, do NOT cut the wire to the solenoid. Then put the game in switch test - do you know how to access the switch test? The how to is on page 19 of the manual. Remove all three balls from the trough then test the switches by pushing a ball in to the trough from the trough drain, it should roll in to position in the trough and switches 13 (trough 3), 12 (trough 2) and 11 (trough 1) should activate with trough 11 being retained on the display. Then repeat for the second ball (switches 13 (trough 3), 12 (trough 2) should activate with trough 12 being retained on the display) and then the third ball now only switch 13 (trough 3) should show on the display.

Oh, ok. Thanks for the explanation. I'll run through this procedure next time I'm out there. Thanks again for your help, much appreciated!