Pinball Flippers Not Working: Dead, Weak or Buzzing Flippers on Bally, Williams and Gottlieb

When the flippers on a 1977-1989 solid-state pinball machine stop working, the fault is usually simple, and it is usually not the CPU. How the flippers fail tells you where to look. Both dead at once points to the one thing they share: the relay that powers them during a game, its fuse, or the connectors feeding it. One dead points to that side only: the cabinet switch, the coil, the wiring or the EOS switch. Weak flippers are almost always mechanical wear or dirty switch contacts. A flipper that buzzes, gets hot or burns its coil usually has an EOS switch that is not opening.

Most of these are cheap fixes you can do yourself with a meter and a flipper rebuild kit.

Contents

• How flippers work on older solid-state games
• Both flippers dead
• One flipper dead
• Weak or sluggish flippers
• Flipper buzzing, hot or burning coils
• Flippers that fail after the game warms up
• When the board is the problem
• FAQ
• Sources

How flippers work on older solid-state games

On games of this era, the computer does not fire the flippers. When you press a flipper button, a switch inside the cabinet closes and sends the full coil current straight to the flipper coil. The processor board (the MPU or CPU) does only one job: it switches flipper power on when a game starts, and off at game over or on a tilt. It does that with a relay.

The coil itself is dual-wound. It has a strong, low-resistance power winding that throws the flipper up, and a weaker, high-resistance hold winding that keeps it up while you hold the button. A small switch at the end of the flipper's travel, the EOS (end-of-stroke) switch, makes the change. On these older games it is normally closed at rest and opens when the flipper reaches the top, dropping the coil onto the hold winding.

Where the flipper relay lives depends on the maker:

• Bally and Stern (1977-1985): the flipper relay is on the solenoid driver board (the Bally AS-2518-16 and its equivalents), switched by one of the driver transistors along the bottom edge of the board.
• Williams System 3-7: a flipper enable relay sits on the driver board, close to connector 2J11 on System 6.
• Gottlieb System 1 and System 80: the game-over relay, called the Q relay, pulls in when a game starts. On System 80 its coil is fed through the normally closed contacts of the T (tilt) relay, so a tilt drops it out, and the Q relay powers not only the flippers but also the slingshots, pop bumpers and kickers.

If the board names are new to you, our guide to pinball electronics explains how the MPU, driver board and power supply fit together.

Both flippers dead

Two coils rarely fail at the same moment, so look at what they share.

1. Is a game really running?

Flippers only work during a game. Start one: does it serve a ball? Is TILT lit? A tilt switch that is touching, such as a plumb bob hanging off-centre, will keep the flippers off even though the game looks as though it started.

2. Listen for the relay

Put your hand near the relay and start a game. You should hear or feel it pull in. On a Gottlieb System 80, if the Q relay does not pull in, check the T relay contacts: Q is fed through them. Owners on Pinside with a System 80 James Bond went straight to these two relays when troubleshooting, and cleaning their contacts is the usual first step.

3. Check the fuse, on both ends

Find the fuse that feeds the flipper or solenoid supply in your game's manual. Test it for continuity out of the holder, then check for voltage on both ends of the holder with the game on. A good fuse in a corroded holder is still an open circuit. On a Gottlieb Raven with both flippers dead, forum helpers asked exactly this, and also whether pop bumpers and other coils still worked. That second question matters: if other coils are dead too, the fault is in the shared supply, not the flippers.

4. Check the connectors to the relay's driver

The relay is switched by the MPU through the driver board, so a bad connector between them can drop it out. In one solved System 80 case, the flippers and the ball release both failed now and then. The shared cause was a corroded MPU-to-driver connector. Cleaning and re-tensioning the pins fixed it, with no parts replaced.

5. On Bally and Stern: find the relay's transistor

Pinside technicians describe a quick test on the Bally solenoid driver board. With the game switched on, ground each transistor tab along the bottom edge in turn with a clip lead to the ground braid, and listen for the relay click. Be careful: grounding a transistor tab fires whatever coil it drives, so touch briefly and move on if a coil fires. Once you find the relay's transistor, hold it on and try the flippers:

• Flippers work: the transistor or the chip driving it is the likely fault.
• Flippers still dead: look at the connectors on the board's edge. A failed relay contact is less likely.

One flipper dead

If one side works and the other does not, the relay and fuse are fine. The fault is between the working relay and that one coil.

• The cabinet switch. Behind each flipper button is a switch carrying the full coil current. Its contacts burn and pit. Look at them with the game off. On pre-1992 games these are tungsten contacts, and filing them clean or replacing the switch is the normal fix.
• The coil and its wires. Look for a wire broken off at a coil lug, or a lug that has cracked. Then measure the coil's resistance with the game off and compare it with the working side. Our guide to testing a pinball coil with a multimeter walks through it.
• The EOS switch. Check it for continuity at rest. A broken or badly bent EOS can leave the power winding out of the circuit.
• Jumper tests. Owners diagnosing a dead flipper on a Bally Dolly Parton checked for voltage at the coil, bypassed the cabinet switch with a jumper, and briefly jumpered the coil's switched lug to ground during a game. Keep jumpers brief: a coil held on will overheat.

Weak or sluggish flippers

Weak flippers are rarely electronic. Home Pinball Repair lists mechanical wear as the main cause:

• A worn crank link. The holes in the link should be round. Over time they wear oval, the plunger travels further before it does any work, and the flipper loses power.
• A mushroomed plunger or coil stop, which binds in the coil sleeve.
• A weak or broken return spring.
• Dirty or badly adjusted switches. Both the EOS and the cabinet switch carry full power on these games. Burnt contacts mean less current reaches the coil.

A flipper rebuild kit covers most of this: coil stop, crank assembly (plunger, link and crank arm), EOS switch, spring and coil sleeve. If only one side is weak, also check that someone has not fitted a different coil there.

Flipper buzzing, hot or burning coils

If a flipper buzzes when held up, gets hot, or has burned its coil, suspect the EOS switch first. When the EOS does not open at the top of the stroke, the coil stays on its power winding the whole time you hold the button. The power winding is not built for that, and it cooks. Marco Specialties puts it plainly: coils burn when the EOS switch does not open.

The EOS should be closed firmly at rest and open just slightly at full stroke. Adjust it, clean the contacts, and replace it if the contacts are badly eroded. If you had to replace a burned coil, fix the EOS before you fit the new one, or it will go the same way.

A flipper that stays up without anyone pressing the button is a different problem: a cabinet switch welded shut, or a shorted wire. Turn the game off straight away. Our article on a pinball coil stuck on explains how to stop the damage and find the cause.

Flippers that fail after the game warms up

Faults that come and go with heat or a knock are nearly always a connection, not a component. One Williams System 6 owner had flippers that worked when cold, then refused to come on at game start once the machine warmed up, unless he thumped the backbox. The cause was cracked solder joints on the driver board at 2J11 and at the flipper relay next to it. Reflowing those joints with fresh solder and flux fixed it. As one forum member noted, the header pins on these Williams boards are cut very short, which makes the joints prone to cracking.

The same applies to Bally games that lose the flipper relay after a few plays. Clean and reseat connectors, reflow dull or ringed header pins, and only then suspect parts.

When the board is the problem

Do the cheap checks first: tilt, relay contacts, fuse, connectors, cabinet switches, EOS and a rebuild kit. They fix the large majority of flipper faults, and a new board will not fix any of them.

Replacing a board starts to make sense when the relay's driver keeps failing, the board has cracked or lifted pads from years of repairs, or the same board is also causing other trouble. Your options, by system:

• Bally / Stern 1977-1985: BallyDri replaces the AS-2518-16 solenoid driver board, and BallyFA replaces the MPU.
• Williams System 3-7: WillFA7 replaces both the MPU and driver board, so the short-pin header joints are no longer in the path.
• Gottlieb System 80 / 80A / 80B: Godri80 replaces the driver board, or GottFA80_Plus replaces the MPU, driver and power supply together.

We test boards before they ship and support them afterwards. If you are unsure whether you need one, ask first. Often the honest answer is an inexpensive switch or a cleaned relay contact.

FAQ

Why don't my pinball flippers work until a game starts?

That is normal. On 1977-1989 solid-state games, a relay switched by the MPU only powers the flippers during a game. At game over or on a tilt, the relay drops out and the flippers go dead.

Why did both flippers stop working at the same time?

Look at what they share: a tilt switch that is touching, the flipper relay (the Q relay on Gottlieb), its fuse, or the connector between the MPU and driver board. Two coils rarely fail together.

Why is one flipper weak?

Usually mechanical wear: an oval-worn crank link, a mushroomed plunger or coil stop, or a tired spring. Dirty EOS or cabinet switch contacts also cost power. A flipper rebuild kit fixes most cases.

Can I file the flipper button switch contacts?

On pre-1992 games, yes. The cabinet switches have tungsten contacts that carry full coil power, and filing them or replacing the switch is normal. Do not file the low-power gold or silver switches used on later computer-controlled flippers.

Why does my flipper coil get hot or burn out?

Usually the EOS switch is not opening at the top of the stroke, so the coil stays on its power winding while you hold the button. Adjust or replace the EOS before fitting a new coil.

What is the Q relay on a Gottlieb pinball?

It is the game-over relay on System 1 and System 80 games. It pulls in when a game starts and powers the flippers. On System 80 it also powers the slingshots, pop bumpers and kickers, and it is fed through the tilt (T) relay, so a tilt drops it out.

Sources

• Marco Specialties: Learning about EOS switches in pinball — power and hold windings, EOS normally closed on older games, burned coils.
• Home Pinball Repair: Pinball flipper rebuilding — causes of weak flippers, rebuild kit contents, filing tungsten cabinet switches.
• Home Pinball Repair: Troubleshooting early Bally and Stern pinball machines — flipper relay on the solenoid board, flippers switched by cabinet switches.
• Pinside: How to test flipper relay on solenoid board, Bally/Stern
• Pinside: Classic Bally flippers not working (Dolly Parton)
• Pinside: Flippers not active when starting a new game, Williams System 6
• Pinside: Williams System 7 flipper coils not working — flipper enable relay on the driver board.
• Pinside: Gottlieb System 80 Q relay / T relay, James Bond
• Pinside: Solved, Gottlieb System 80 losing flippers and ball release intermittently
• Pinside: Gottlieb Raven, both flippers stopped working
• Pinside: Bally Xenon losing flipper relay after 4 or 5 plays

Still stuck? Tell us your machine and exactly what the flippers do: both dead, one dead, weak, or hot. Our technical support is free, before and after purchase, including when the answer is a cheap fix you can do yourself.