Wierd coils on Bally EM

[DanLewell]

They probably arent wierd but this is the first EM I've worked on and they look weird to me!

Some of the coils on the Bally King Tut that I'm trying to save have what looks like two windings, like a high power and low power type of coil but laid out strange like in the pics.

If it were flippers I would assume that's what it is, but it's not just flippers.
It has the same style of coils on the outlane gate, and on the pop bumpers.

All the other coils look normal.

Can anyone explain what's going on with these and how they work?

 

[astyy]

Dan I saw your post on pinside about King Tut, good stuff would like to see some pictures

Yes that is a dual wound/3 terminal coil - E-184-265 equivalent to 25-600/31-1000, here is a list of the conversions for the old Bally numbers - http://user.xmission.com/~daina/tips/pub/tip0479.html

As you say they appear on other mechs from that era that have EOS and are held by their associated relay until it releases. I don't have access to King Tut schematics but here's the equivalent from my Rocket III showing the two windings of a similar coil on a Thumper Bumper - 4.2 Ohms pull and 32.2 Ohms hold (this machine has 4 bumpers and they pull in alternate pairs in this example controlled by a "2 - 4 Relay".) I'm not sure why the bumpers needed this but these machines were super engineered for everything to happen in a precise sequence controlled by the relays and score motor, so the bumper couldn't be reactivated until everything related to it's action, in this case probably a score increment was completed - that would happen super fast so they could keep bumping as we like it!

All the best for your project, listen out for coils locking on and buzzing when you start testing it.

 

[DanLewell]

Cool, thanks for getting back to me about it. I guessed it would be that but not used to hold coils on anything other than flippers.

I've got a schematic for it so that bit will look familiar when I get round to looking at it when I put it all back together.

I've got loads of pics from the top side strip down, I'll start a thread about it once I get a bit further along with it. It might give people nightmares though, it was covered in mold and rust from being stored in a damp garage.

 

[astyy]

Cool, thanks for getting back to me about it. I guessed it would be that but not used to hold coils on anything other than flippers.

Yeh agreed, the Free Ball Gate makes sense to hold it open on low power, the 60s Thumper Bumpers were probably just over engineered as they'd dropped the dual coil solenoid by the 1970s.

Btw, it covers a slightly later machine but this is an excellent resource to understand Bally EMs via their schematic;
https://pinside.com/pinball/forum/t...cribed-from-beginning-to-end-bally-bon-voyage

 

[Doug]

Late Bally EMs were beautifully engineered and are nice to work on. Those coils, if duff, can be replaced with normal looking ones, from Pinball Resource.

 

[drwpsw86]

I need help with my. Replacement coil for my king tut Machine. The old coil is a 3 prong hookup and the replacement one #AF-25-600/31-1000 has 3 prong that are in a straight line. Unlike the original shown in your pic, I am confused as to which wires go where? Can anyone help me with this? Thanks

 

[pinballmania]

As long as the end of stroke switch is joined across the two terminals that connect the finer winding and the two other wires are attached to the terminals with single winding connections you will be ok.

 

[drwpsw86]

Thanks, that is what I was looking for. thanks again for taking the time to show this schematic . Excellent. I will let you know how this works out after I complete the install.