(Topic ID: 306932)

Gottlieb "300" score motor continuously running

By NickNitro

7 months ago



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  • 10 posts
  • 3 Pinsiders participating
  • Latest reply 6 months ago by NickNitro
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#1 7 months ago

Hi all,

I have another pin that i'm trying to fix. Initially on first power nothing would happen and the lights on the playfield weren't on. After adjusting the tilt relay the lights came on and the score motor just keeps running.

I tried this which was on another post and hasn't fixed my issue (but found 2 un-soldered wires that I fixed) : https://www.pinwiki.com/wiki/index.php?title=EM_Repair#Gottlieb.C2.AE_Score_Motor_will_Not_Stop_Running:_Frequent_Cause

things I've noticed is the score reels aren't resetting but if I hold the Z1 and Z2 relays, the reels do zero out.
The game over relay and the 1st ball relay are the only ones that stay energized

if anyone knows of things I can look for it would be greatly appreciated!

#2 7 months ago
Quoted from NickNitro:

the score motor just keeps running

One or more of these switches / relays is stuck closed. Which one(s)?

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#3 7 months ago

Wow thanks! You made that sound so easy to fix hahaha!
I'll get right on that!

#4 7 months ago

Finding out which switch is closed might just be the first step (for example) if a relay is locked on. In that case the next step in finding the root cause would be to determine why that relay is locked on.

#5 7 months ago

So I found that the AX trip relay isn't engaging, once I flip it and set the relay to open the motor stops. The coil is showing 3.3 Ohms, that sounds pretty low... would you assume it to be burnt?
And if not am I correct is thinking this would be the right path to check next?

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#6 7 months ago

If the AX reset coil never opens its motor running switch circled in my post above then yes, the next step is to find out why.
If you're doubt the health of the AX reset coil, remember you have to measure its resistance with one wire disconnected. You could also "hot wire" it with Alligator clip jumper wires, or swap it with the BX reset coil since they have the same part number.

Once you satisfy yourself that the AX reset coil is OK, I suspect that the P5A switch (in your posted schematic fragment) isn't closing because the Player unit isn't making it to its own fully reset position. (See step 6 on page 2 of the "300" manual)
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#7 7 months ago

The 300 schematic provides a pretty good example of why you can't reliably measure the resistance of a coil in circuit:
Parallel coil resistance measurement (resized).jpg
If you clip your meter to the solder lugs of the AX Reset coil without removing one lug from the circuit you'll measure the resistance of all five of these coils in parallel.

/Mark

1 month later
#8 6 months ago

Ok so I know it's been a while but I finally had time to work on it again. Thanks for the info!

I checked the AX coil and it's good, once I brought the player unit to the proper position manually the machine stops.
If I turn it off and back on, the 1st ball relay (U) and hold relay (R) are energized and the tilt light is on with no lights on the playfield.

If I press the replay button, nothing happens. If I manually flip the start relay or the tilt hold relay the machine is "playable" (doesn't kick out ball or reset anything)

Now i'm not sure if I should be looking at the start relay or the tilt hold relay as an issue or maybe something else?

#9 6 months ago
Quoted from NickNitro:

If I press the replay button, nothing happens.

If pressing the Replay button doesn't activate the Replay Button relay (V),
Inspect and diagnose this circuit with Alligator clip jumper wires

https://pinside.com/pinball/forum/topic/gottlieb-big-shot-repair#post-6305153
http://www.planetimming.com/Pinball/troubleshooting/EM%20Troubleshooting.pdf
http://www.pinrepair.com/em/index3.htm#features
Example of a pinsider actually doing this https://pinside.com/pinball/forum/topic/red-baron-tech-question#post-5858156

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#10 6 months ago

Thanks so much! That's a lot of good info I can work with right there. I never even thought of bypassing with jump wires!

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