The majority of coil part numbers indicate the construction method of the coil. The first letter or two indicates the type of sleeve or the position of the wire terminal lugs.

Example of a coil part number AE-23-800   In our example; 23=wire gauge; 800=number of turns of wire.

Bally/Williams pinball solenoid coils have places for three terminal lugs; left edge, middle, and right edge of the coil's plastic base. The positions are as viewed with the lug end of the coil facing you and the lugs on top of the plastic coil base.


The 'AL' and 'AR' coils are used when the lugs on an 'AE' coil would be in the way of a metal coil mounting bracket or any other close mechanical device.
Part number suffix (or numbers following a coil part number, AE-23-800-04) and letter prefixes (SA3-23-850DC) indicate the coil sleeve type used (metal or plastic sleeve and length), diode polarity, wire lug placement, length of the wire lug at the base of the coil or the length of the mounting insulator or coil base (EX. AE-23-800-01).

The first digits in the coil part number (Ex. 23-550) indicate the American wire gauge.

Wire Gauge: The higher the American Wire Gauge number, the smaller the diameter of wire. A small diameter wire has more resistance then a large diameter one and will take fewer turns of wire for a given coil operational voltage.  This makes the coil cheaper to manufacture because wire is sold by the pound and not by the length of the spool of wire . This can also lead to a coil that is easy to burn because small sized wires heat up faster then large diameter wires.

The last digits (Ex. 23-550) indicate the number of turns of wire on the coil.

Number of Wire Turns Rule: The more turns of wire the weaker the coil. The fewer the number of wire turns equates to a stronger pull-in strength of the solenoid coil.
Weaker coils (large number of turns of wire, Example a 27-1100 coil) can withstand long activation times. If a coil is built with enough turns it can be activated indefinitely without coil destruction.

Our example solenoid coil (23-550) would be a very strong coil. A typical use for a coil this strong would be in an outhole ball eject mechanism. An outhole ball eject device is only activated for a short period of time but must push a heavy game ball up a steep slope or lift it out of a hole to move the ball into the ball shooter lane.
Coils that may be activated for a long time (either by design or by a faulty/shorted playfield switch (EM pinball only) usually have at least a 1000 or more turns of a large diameter wire.  Score reel, chime, 'lock' relay and the 'hold' coil on most early flipper coils are examples of a coil designed to be activated for a long time without overheating.

Flipper coils usually have two sets of part numbers (Ex. 21-550/26-1200) because they have two coil windings on the same coil body. The first set of part numbers (21-550 in example) indicate the strength of the flipper (pull in coil used to raise the flipper). The last set of numbers (26-1200) indicate the coil strength used to hold the flipper fully upright (hold in coil). The number of wire turns on the second set of the flipper coil part number is always larger then the first number of wire turns because the coil does not need to be strong when holding the flipper upright. The second coil also has to be able to be held in (coil activated) permanently without burning up the coil.

Flippers on the most modern pinballs use only one coil winding. One winding flipper coils are supplied with two different voltages at different times in the operation of the flipper  (These kinds of flippers are sometimes referred to as "sold state" flippers even though they are still operated by a solenoid coil). A higher voltage (usually 50 volts) is used to move the flipper and a lower voltage is used on the same flipper coil winding to hold the flipper upright. This new type of coil doesn't have two sets of coil winding numbers in its part number. In fact, single winding flipper coils usually have only an arbitrary, non-specific part number on them. This part number doesn't indicate anything about how the coil was constructed. For example; 090-5020-20.

Coil Voltages - Early EM pinball and late model electronic games use a relatively high 50 volt solenoid coil voltage. This higher drive voltage produced coils with very strong pull in strengths and a wider range of coil strength adjustment then the much lower voltage 24 volt solenoid coils. Higher coil voltage speeds up the game play and allows for mechanisms that have to physically lift a game ball and plunge it back onto the playfield such as a Vertical Up Kicker (V.U.K.). The 50 volt source was abandoned during the "middle ages" of pinball (late 70's to 80's games) because of the shock potential of this high a voltage. Players could receive painful shocks if the game was not properly grounded either by the grounding lug on the power cord or by a missing ground wire on a metal game part.
If a 24 volt coil needed more strength or a slightly faster plunger pull in speed, then the 24 volt Alternating Current supply was converted to Direct Current for only a few coils inside of the game.  This current type conversion (AC to DC, converted by bridge rectifier) was done mostly on Pop Bumpers and Sling Shot coils during the middle ages of pinball.
The higher 50 volt supply (DC current this time) was reintroduced in late model pinball games because grounding methods slightly improved and the typical game player demanded higher game speeds and stronger flippers were needed for the steeper sloped ramps and playfields of the modern pinball game. Also, greater playfield mechanism complexity began to be used on modern pinball games requiring very strong solenoid coils. Coil Voltage Note: Because voltage mesurements are affected by the method of measurement and the condision of the circuit (loaded or unloaded circuit, Peak versus RMS versus Adverage voltage readings) and it is  commonplace to indicate a standard supply voltage when presenting a coil voltage (24 volts instead of 28 volts - 50 instead of 60 volts), all voltages listed on this page are the adverage or most common voltage measurement. Voltage readings in the real world may very slightly from what has been presented on this arcade coil charts page.

Coil Part Number Substitutions:  It is always best to use a coil with a small wire gauge number (large diameter wire) and same number of wire turns as the original coil only if the exact part number can not be found. For example; a 23-800 coil will have the same pull in strength as a 26-800 coil, however, the larger wire used in the 23-800 will take a longer time to heat up and therefor the coil should last longer without overheating inside of a game.
It is usually the case that the original coil part number can be bought new and a coil part number substitution should only be considered when a new replacement coil is not available.
Pinball game coils have been specifically designed to operate the mechanism they are installed in. If a coil is no longer available and two potential substitute coils are manufactured then install the coil with the lower wire gauge number and the same wire turns number. This all assumes there is no difference in the construction of the original and the substitution coils except for their wire diameter. For additional information on coils see the Coil Body Differences by coil manufacturer section on this page and our Tech Tips and the additional Tech Tips pages.

Gottlieb is always the exception to any industrial coin op coil or part number scheme.  Their coil part numbers do not provide any useful information and usually start with the letter "A".
A substitute for Gottlieb coils can be found by matching a known good Gottlieb coil's ohmage with the ohmage of a Bally coil or by matching a typical coil's function.

Coil Body Differences - Bally and Gottlieb use the same coil body. A typical Williams or Data East coil uses a 1/16 of an inch shorter coil body.
Vast differences exist for coil stops between pinball manufacturers. These differences include stop height, width and mounting hole spacing.

Solenoid coil sleeve, coil magnet and flipper bushing  information.

Other pinball game and coin-op arcade technical info can be found on Pinball Medic's Tech Tips or Tech Tips Two pages.

Pinball Type Abbreviations:
EM = Electromechanical (score reels, relays)   SS = Solid State (digital score displays, chips (integrated circuits))
VUK=Vertical Up Kicker   G. P.=General Purpose Application

The charts below show solenoid coil numbers and typical application. They do not indicate Pinball Medic's current solenoid coil inventory.
Pinball Medic Amusements does not have any Atari or Zaccaria pinball coils and will not repair these brands of pinball.

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