Jacks To Open (Gottlieb/Mylstar, 1984): faults, diagnosis and System 80A boards

On your Jacks To Open, have the pop bumpers gone dead, has the sound started running on its own, do the drop targets stop scoring, or does the game reset or refuse to start? All four are documented, recurring faults on this specific machine — not vague System 80A generalities — and all four have known causes. This page walks through what owners actually found, and what fixed it.

About Jacks To Open (Gottlieb/Mylstar, 1984)

See it: full photo gallery for Jacks to Open on IPDB (#1282) · Pinside machine page and owner photos · the 1977 electromechanical original on IPDB (#1281)

Jacks To Open is a four-player System 80A game on a poker theme, released in May 1984 with a production run of 2,350 units. Its pedigree is better than its reputation: the game design is credited to Ed Krynski, the most prolific designer Gottlieb ever had, with artwork by David Moore and sound and music by Craig Beierwaltes.

It is a remake — and the original is worth knowing about

Jacks To Open is a solid-state remake of Jacks Open, Krynski's own single-player electromechanical game from 1977. The layout carried across almost intact: a bank of nine drop targets, three pop bumpers and two slingshots, with the drop targets spelling out poker hands. On the EM original you worked up through a pair of Jacks, three Queens and a Full House to a Royal Flush for a replay, with the top rollovers automatically completing the current hand and lighting 5,000-point outlanes.

The one deliberate change in the 1984 version is the order of the drop targets. If you have played the EM and your muscle memory keeps sending the ball to the wrong target, that is why.

For context on how the two sold: Gottlieb built 2,975 of the 1977 Jacks Open replay version plus 610 of its add-a-ball sibling Lucky Hand, against 2,350 of the solid-state Jacks To Open. None of them are rare, but the Museum of the Game census ranks this title low for collector prevalence — people own them and play them rather than collect them, which is usually good news for a buyer.

The rare variant: ten alphanumeric test machines

This is the detail that matters if you are buying boards. Production Jacks To Open machines use seven-digit numeric displays. But a tiny run of roughly ten alphanumeric "test" machines was built, and collectors note they predate both Gottlieb's own alphanumeric releases and WICO's AFTOR by about a year — making them a genuine footnote in display history.

If you happen to own one of those ten, do not assume standard board and display compatibility. Talk to us with photographs of your display boards and backbox before ordering anything. For the other 2,340 machines, everything below applies normally.

Gottlieb or Mylstar?

If your paperwork says Mylstar Electronics, that is correct and not a sign of a parts-bin machine. Columbia Pictures owned D. Gottlieb & Co. from 1976 and renamed it Mylstar Electronics in 1983, after Coca-Cola acquired Columbia. Columbia shut Mylstar down in September 1984 — a few months after this game shipped — and in October 1984 a management group under Gilbert Pollock bought the pinball assets and founded Premier Technology. That is why IPDB files this game under Mylstar while Pinside and the Museum of the Game list D. Gottlieb & Co. Search both names when hunting parts.

• Manufacturer: D. Gottlieb & Co. / Mylstar Electronics
• Year: 1984 (May, per Pinside)
• IPDB: #1282 (the 1977 EM original is #1281)
• Production run: 2,350 units
• Electronic system: Gottlieb System 80A
• Display: seven-digit numeric, 4 players (plus ~10 alphanumeric test machines)
• Design: Ed Krynski · Art: David Moore · Sound & music: Craig Beierwaltes
• Playfield: 9 drop targets, 3 pop bumpers, 2 slingshots, 2 flippers, manual plunger
• Not fitted: no multiball, ramps, magnets, kickbacks or spinners
• Weight: around 229 lb (104 kg)
• Based on: Jacks Open (Gottlieb, 1977), drop target order changed

Faults specific to Jacks To Open

This machine has a real, usable repair record. Here is what keeps coming up.

All three pop bumpers dead — check connector A1J6 first

This is the best-documented fault on the game, and the fix is specific enough to be worth memorising. The pop bumper driver board takes its +5 V on pin 18 of MPU connector A1J6 (wire colour 688) and its ground on pin 9 (wire colour 333). Lose either and all the bumpers go dead at once — which is the giveaway: one dead bumper is mechanical, three dead bumpers is almost always this connector.

Two things make it worse on these machines. First, A1J6 sits in the battery leak zone, so corrosion reaches it early. Second, the connector can work partly loose when you fold the backbox down — meaning the fault can appear immediately after you have been working inside the head.

In the case documented on Pinside, the wires themselves looked fine. The owner cleaned the connection, removed and cleaned the main board, and in doing so found that a previous owner's battery modification had been left with loose wiring. Reassembled, all three bumpers worked. The lesson generalises: on a System 80A, inspect any earlier battery mod before you suspect the driver board.

The F12 fuse keeps blowing on the centre pop bumper

One owner reported F12 blowing immediately after starting a game, specifically on the centre pop bumper — and it kept blowing even after a new driver board went in. In that thread the root cause was never pinned down, so we will not pretend otherwise.

What it tells you is useful anyway: a fuse that blows instantly with a known-good driver board points downstream, not upstream. Check the bumper coil itself for a shorted winding, the coil sleeve and the switch for a dead short, and the wiring to that one bumper for a pinch to ground. Replacing the board will not fix a shorted coil.

Sound playing continuously, during play and at rest

A distinctive complaint on this game: the machine makes sound continuously, including when nobody is playing. The fix that worked is almost absurdly simple — carefully remove the sound ROM from the sound board and reseat it. The owner who suggested it reported success with the same trick on three of his own System 80A games, which makes this a family-wide fix worth trying before you spend anything.

Do the ground mods at the same time (see below). And watch for the sting in the tail of that thread: while troubleshooting, the owner found the sound board's own power supply running hot, which is a board-level problem that reseating a chip will not cure.

The board in question is the MA-309, the System 80A A6 sound board. It is electrically the earlier MA-216 with the VOTRAX SC-01 speech chip and its support circuitry removed to save cost, so Jacks To Open has sound effects but no speech — useful to know, because a replacement board does not need a speech option. The MA-309 has long been discontinued as a new part.

Drop targets and bottom lanes stop scoring

Another documented case: the last three drop targets and the four bottom lanes all stopped registering after working normally. The diagnosis pointed at connectors — reseating and, where necessary, replacing them.

The pattern is the diagnostic clue. A group of adjacent switches failing together is a wiring, connector or matrix problem; a single target failing is mechanical. On a nine-target bank that gets hammered every game, also check the target switch blades and the switch actuator alignment before you condemn anything electronic. Connector replacement comes up often enough on this title that owners discuss re-connectoring the whole machine as a restoration step.

Start button and credits not working

Reported on this game and worth treating as a switch-matrix and connector question rather than a CPU failure. Check the start button switch itself, then the connector path back to the CPU board, then the coin door wiring.

Tired power supply capacitors

On one Jacks To Open, two ageing orange filter capacitors needed replacing, and the practical note from that thread is that a single 10,000 µF capacitor can substitute for two smaller ones. Forty-year-old electrolytics are a reasonable thing to replace on principle, and sagging filter capacitors cause exactly the intermittent resets people blame on the CPU board.

Displays

Missing digits and segments are usually a dirty or unseated connector — clean and reseat the edge connectors and the J2/J3 links first. Beyond that, the Gottlieb seven-digit display units do fail, both the glass tubes and their small driver boards, and both come up in this game's threads. One unbreakable rule: never plug or unplug a display with the machine powered on.

Before anything else: the battery and the grounds

Two System 80A jobs underpin every fault above, and skipping them wastes your time.

The NiCad battery. The original CPU board carries a rechargeable NiCad soldered in place. After four decades it leaks, and the electrolyte creeps along traces and wicks under chip legs — it is the single biggest killer of System 80 boards, and as the bumper fault above shows, it sits right next to the connector that feeds your pop bumpers. Remove it. If someone already did, check how well.

The ground mods. Gottlieb used single-sided edge connectors that oxidise and lose spring tension, leaving boards with a floating ground. The symptoms are everything-and-nothing: random reboots, flickering lights, sound cutting in and out, coils firing unbidden. The standard fix is to run an extra 18-gauge wire (green by convention) from each board's ground — easily picked up at a capacitor leg — to one common ground point, usually the power supply mounting bracket with the paint sanded back to bare metal, and to tie the head and cabinet grounds together. Keep the 45 V solenoid ground separate so a coil short cannot find your logic boards. Experienced owners on this very game say the same thing: do the ground mods before chasing anything else.

After that, the rest of the System 80A checklist applies — measure 5 V at the power supply and again at the CPU board, check the bridge rectifier, regulator and Q1, and bear in mind that the 6532 RIOT chips on the CPU board are a known failure point that can leave you with no boot or a dead switch matrix.

Replacement boards compatible with Jacks To Open

These are System 80/80A/80B boards and fit this machine as they fit its siblings. We test every board before it ships and support it afterwards.

• GoPOP80 — pop bumper driver board, replacing the original MA-922 / A-19741. The relevant one for this game. Check A1J6 first, though: if the board is being starved of +5 V, a new board will be just as dead.
• GottFA80_Plus (Light) — all-in-one CPU + Driver + power supply board, without sound.
• GottFA80_Plus (Full) — the same board with the sound section integrated.
• Gosof — replacement sound board. For Jacks To Open the no-speech configuration is correct, since the original MA-309 has no speech circuitry.
• Godri80 — replacement Driver board.
• Lisy80 — CPU board with web-based diagnostics, which is particularly handy on a switch-matrix fault like the drop target problem above.

LISY is an independent, free DIY project by its own developer, documented at lisy.dev — full credit for it belongs there, not to us.

One compatibility caveat. Everything above assumes a standard production machine with seven-digit numeric displays. The handful of alphanumeric test machines are a different proposition — get in touch with photos before ordering if you think you have one.

All of these install Plug & Play, run without a battery, and come with free tutorials and support. Contact us with what is silkscreened on your existing boards and we will tell you what you actually need.

Step-by-step diagnosis

1. Powered off, look first. Find the NiCad battery on the CPU board, look for creep and green corrosion, and remove it. If it has already been removed, inspect the quality of that modification — loose battery-mod wiring has caused real faults on this game.
2. Inspect A1J6. Especially if your pop bumpers are dead or you have just folded the backbox down. Pin 18 is +5 V, pin 9 is ground.
3. Do the ground mods. 18-gauge wire from each board to a single common ground point, head and cabinet grounds tied, 45 V solenoid ground kept separate.
4. Power supply. Measure 5 V at the supply, then again at the CPU board. Replace tired filter capacitors while you are in there.
5. Connectors. Re-pin oxidised Molex connectors, especially the MPU-to-Driver link. Groups of switches failing together almost always means connectors.
6. Sound. Reseat the sound ROM on the A6 board before buying anything, then check the board for an overheating regulator.
7. Drop targets. Nine targets take a beating — check switch blades, actuator alignment and the target bank mechanism alongside the electronics.
8. Final test. Boot, credits, start button, all three bumpers, the full target bank, bottom lanes, displays and sound.

FAQ — Jacks To Open (Gottlieb, 1984)

My pop bumpers don't work on Jacks To Open.
If all three are dead at once, check MPU connector A1J6 before anything else: pin 18 carries +5 V and pin 9 the ground to the pop bumper driver board, and losing either kills all the bumpers. The connector sits in the battery leak zone and can also work loose when the backbox is folded down. If the board itself is faulty, the GoPOP80 replaces the original MA-922 / A-19741.

My Jacks To Open makes sound constantly, even when nobody is playing.
Reseat the sound ROM on the sound board — it is a documented fix on this game and on System 80A machines generally. Do the ground mods too. If it persists, check whether the sound board's power supply section is overheating, which needs the board replaced rather than reseated.

My drop targets and bottom lanes have stopped scoring.
A group of switches failing together points at connectors rather than chips — reseat them, and replace them if the pins are tired. Then check the target switch blades and actuator alignment mechanically. A CPU board with diagnostics makes this much faster to pin down.

The F12 fuse blows as soon as I start a game.
On a reported case this happened on the centre pop bumper and continued even with a new driver board, and the cause was never published. Look downstream: a shorted bumper coil, a collapsed coil sleeve, a shorted switch, or wiring pinched to ground. A new board will not fix a shorted coil.

Is Jacks To Open the same game as Jacks Open?
Almost. Jacks Open (1977) is Ed Krynski's single-player electromechanical original; Jacks To Open (1984) is his four-player solid-state remake on System 80A. Same nine-drop-target poker layout, but the order of the drop targets was changed. The 1977 game also had an add-a-ball sibling called Lucky Hand.

How many Jacks To Open were made, and what is one worth?
2,350 of the 1984 solid-state version. It is not a rare machine and the Museum of the Game census ranks it low for collector prevalence, so condition and working order drive the price far more than scarcity does. Published value estimates for this title are thin, so judge the machine in front of you.

Why does my machine say Mylstar rather than Gottlieb?
Same company. Gottlieb was renamed Mylstar Electronics in 1983 under Columbia Pictures, and Columbia closed Mylstar in September 1984, shortly after this game shipped. IPDB files it under Mylstar; other databases say Gottlieb. Both are right.

Does a battery-free replacement board keep settings and high scores?
Yes. Modern replacement boards use non-volatile memory: no battery, no future corrosion, and your settings and scores survive power-off.

Useful guides

• GoPOP80: plug-and-play pop bumper driver board (replaces MA-922 / A-19741)
• Video: troubleshooting Gottlieb System 80/A/B drop targets with the Lisy80
• GottFA80_Plus: the all-in-one board for Gottlieb System 80/80A/80B
• How to install a replacement pinball board: the Plug & Play guide
• Repair or replace your pinball machine's board: which should you choose?
• How much is my pinball machine worth? Value, pricing and appraisal guide

See also

• Royal Flush Deluxe (Gottlieb, 1983) — the other System 80A card game
• Touchdown (Gottlieb, 1984)
• Ready Aim Fire! (Gottlieb/Mylstar, 1983)
• Rack 'Em Up (Gottlieb/Mylstar, 1983)
• Alien Star (Gottlieb, 1984)
• The Games (Gottlieb, 1984)
• El Dorado City of Gold (Gottlieb, 1984)

Sources & further reading

• IPDB — Mylstar "Jacks to Open" (#1282)
• IPDB — Gottlieb "Jacks Open", the 1977 EM original (#1281)
• Pinside — Jacks to Open machine details (production run, credits, remake note)
• Pinside — "No Bumpers Working Jacks To Open" (A1J6 pin 18 / pin 9, battery mod finding)
• Pinside — "Gottlieb Jacks To Open sound issue" (sound ROM reseat, overheating supply)
• Pinside — "Jacks to Open" (F12 fuse, filter capacitors, targets and lanes not scoring)
• Pinside — "RARE Alpha Numeric Jacks To Open Test Machine" (the ten prototypes)
• Pinside forum index — Jacks to Open (displays, start/credits, connectors)
• Pinrepair — Gottlieb Jacks Open 1977 (EM rules, layout, production figures)
• Museum of the Game / KLOV — Jacks to Open census and specifications
• Wikipedia — Gottlieb, Mylstar Electronics and Premier Technology timeline
• Pinball Help — recommended Gottlieb System 80 ground mods
• Flipprojets — history of Gottlieb audio boards (MA-216, MA-309, SC-01)

Own a Jacks To Open? Send us a photo and we'll add it here with credit — get in touch.