Rewinding an unobtainable coil onto its old frame

Steps

• Unwind all the burnt wire. Check the sleeve: if the plunger has worn through it, transfer the end pieces to a new sleeve.
• Find the coil's gauge and turns from the schematic key (Gottlieb doesn't give these; use a chart of known Gottlieb coils).
• Choose a donor coil with the same gauge and a similar number of turns, or one whose resistance matches an identical good coil in the game.
• Mount the empty frame on a bolt in a drill chuck; a helper keeps the donor coil turning on a screwdriver shaft with light drag.
• Fix the wire to one lug and run the drill slowly to transfer the wire (about five minutes).
• Sand the enamel off both ends and solder them to the lugs, then measure.

Example: a coil marked 24-965 (24 gauge, 965 turns) was rewound with wire from a 24-900 donor; an exact match isn't needed.

Systems

• Electro-mechanical

Related tips

• Coil frame sizes by maker
• Coil stops by maker
• Coil sleeves and plungers to keep
• Typical EM coil resistances
• EM coil voltage by maker
• What makes a coil stronger or weaker
• Bally C0- coil numbers and their replacements
• When a coil can be measured without unsoldering

Source: Repairing Electro-Mechanical (EM) Coin Operated Games to 1978, Part Two, Clay Harrell (pinrepair.com)