Airport
Gottlieb, 1969When my Airport EM machine, when I score enough the Knocker Coil gets triggered. But, is does not turn off, and just buzzes.
I have a copy of the schematics but am not expert enough on how to follow and diagnose.
The game count on the back box does not trigger but machine is on Freeplay
I am assuming there is some sort of mechanical device to turn on/off the knocker coil.
Thanks
Have you looked at the credit unit in backbox??
Sounds like your knocker contacts on step up are not working properly.On step up,the contacts are closed,then opned by the movement of the step up mechanism.
The knocker also goes through the "W" replay,but my guess is it's a stuck knocker contact in the head.
Your credit unit is probably gummed up and the coil does not make a return as designed
Thanks will start work tomorrow. Are there any articles/videos on how the EM machine works once a bonus score level is achieved.
I am assuming that the trigger for the Knocker coil is being triggered, but as you mentioned, the coil is not being turned off.
Where is the knocker off contact in the head?
Thanks
Back in the head by your credit numbers.The contacts that energize the coils will be on bottom right,and will be sticking out a little by itself. The other contacts are further in the mech that control it.
Check contacts in yellow. They close when your "step up" coil is activated.
Pinside_forum_3153361_701977 (resized).jpgTrying to find the physical location of the W relay from the schematics.
Does the schematics only show "logical" locations and not physical?
Thanks
That's correct - there's no correlation between physical proximity on the schematic and on the machine - just shows electrical connections. You just have to hunt around for it, and hopefully the labels are still there. If not, you can use information like the number of switches on each relay and wire colors to identify relays.
Also, the machine is set to free play and the coil resets when a new game is restarted.
If that makes a difference.
Quoted from classic-chevyguy:Trying to find the physical location of the W relay
See https://gottliebpin.com/archive/GTB-Ref/280/gtb-pb280-cab.jpg
The spring return action of the replay step up coil arm might not be happening. Allowing the knocker switch to stay closed.
Wanna join the discussion? Please sign in to reply to this topic.
Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!
This page was printed from https://pinside.com/pinball/forum/topic/gottlieb-airport-high-score-knocker-circuitry and we tried optimising it for printing. Some page elements may have been deliberately hidden.
Scan the QR code on the left to jump to the URL this document was printed from.
West Barnstable, MA
