Alien Star (Gottlieb/Mylstar, 1984): faults, diagnosis and System 80A replacement boards

Is your Gottlieb Alien Star refusing to start a game, showing whole rows of dead switches, not kicking the ball out, running dim or blank displays or resetting on its own? These are the familiar complaints on a Gottlieb System 80A machine whose original boards — CPU, Driver, power supply, sound — are now past forty years old. Most of them have a known cause and a known cure, and where a board is beyond saving, modern replacement boards (Plug & Play, battery-free) will put the game back on route.

Alien Star also rewards a bit of context. It is one of the more interesting System 80A machines to own, it has a genuine multiball, and the way it plays has a direct bearing on which switches wear out first. So before the fault list, a proper look at the game.

About the Gottlieb Alien Star (1984)

See it: full photo gallery for Alien Star on IPDB — backglass, playfield, flyer and cabinet shots. There is also an owners' Alien Star gallery and game page on Pinside.

Alien Star arrived on 1 June 1984 with a science-fiction theme — ringed planets, a star field and a cover-art alien that owners regularly single out as some of the best artwork of the period. It was designed by John Trudeau, with artwork by Larry Day and sound by Craig Beierwaltes: the same trio behind Touchdown later that year, which makes the two games natural companions in a collection.

The company history behind it is worth a paragraph, because it explains why you will see the game credited three different ways. Gottlieb had been renamed Mylstar Electronics in 1983 under Columbia Pictures ownership. Columbia shut Mylstar down at the end of September 1984, and a management group formed Premier Technology that October to carry on building pinball under the Gottlieb name. Alien Star was made in June 1984, which puts it squarely in the Mylstar period — and sure enough, IPDB and the Arcade Museum both file it under Mylstar, while the boards, the manual and every parts listing call it a Gottlieb System 80A. All of those are correct, in their way. For repair purposes only one label matters: System 80A.

Production came to 1,065 units, which is low. Ownership censuses show very few surviving examples registered, so a parts machine is not something you will stumble across — another reason the original boards are worth either repairing properly or replacing with something that is supported.

Specifications

• Manufacturer: D. Gottlieb & Co. — built during the Mylstar Electronics period; IPDB and the Arcade Museum list it under Mylstar
• Release date: 1 June 1984
• Production run: 1,065 units
• Design: John Trudeau
• Artwork: Larry Day
• Sound: Craig Beierwaltes
• Electronic system: Gottlieb System 80A, 7-digit scoring displays
• Players: up to 4
• Playfield: single level, 2 flippers, 3 pop bumpers, 2 spinners, a lock saucer, A-L-I-E-N stand-up targets, two-ball multiball; no ramps, no drop targets, no magnets
• Ball launch: manual plunger
• Weight: around 225 lb (102 kg) with legs
• Theme: science fiction / space

How it plays — and why that matters for repairs

Alien Star is not a complicated game, but it has one superb scoring idea. You complete the A-L-I-E-N stand-up targets on the right to light the lock on the left, then lock a ball to start the two-ball multiball. Shots to the left spinner cycle a playfield multiplier through 2X, 3X and 5X; the right return lane lights the right spinner for 10X for a few seconds. Stack those and a single spin can be worth 50 times base value, which is how a good player turns one precise shot into a million points. Shots through the right spinner also advance the bonus multiplier, capped at 5X and 29K. Letter progress and lock status carry over between balls, so the game builds.

Three practical consequences for anyone with a screwdriver in hand. Two spinners carrying the scoring means two leaf switches taking a beating. A multiball means the ball trough stages two balls, and the game is fussy about ball position there — which is behind one of the most common "it's dead" complaints below. And five stand-up targets plus a lock saucer means the switch matrix is doing real work; when a chunk of it goes quiet, you will notice immediately.

On the second-hand market, owners have historically talked about $500–750 for a working, presentable machine, with one near-perfect example offered $1,500 and turned down. Those figures come from owner discussions from the mid-2010s and should be treated as a reference point, not a quote — condition drives the price far more than rarity does, and the game has a following for its artwork, its sound and its tournament-friendly multiball.

Common faults across System 80 and 80A

Work through this list before anything else, especially on a machine you have just bought. Most System 80A boards that look dead are not.

• The NiCd battery on the CPU board. It leaks, and the electrolyte eats traces, sockets and chip legs — often travelling under the board where you cannot see it. This is the number one killer of System 80 CPU boards, and it has to be neutralised before any other diagnosis makes sense.
• Connectors and grounds. The System 80 reference documentation is blunt: connectors are the single biggest cause of failure on these games. Boards are grounded through daisy-chained connectors rather than a proper ground plane, so one tired contact can make lamps, coils, relays and sound misbehave all at once. Clean the edge contacts, re-pin the Molex connectors, and run each board's ground to a common point and on to the cabinet ground strip.
• CPU board chips. A 6502 at U1 and three 6532 RIOT chips: U4 reads the switches, U5 drives the displays, U6 handles solenoids, lamps and sound. The symptom usually tells you which to suspect. The battery-backed 5101 CMOS RAM at Z5 is its own source of errors and is reported as "5101" in test 20 on 80A.
• Power supply. The big orange filter capacitor (6800 µF / 25 V) is past its life on every one of these. C1 (470 µF / 100 V) is a frequent reason the ¼ A high-voltage fuse keeps blowing, and the CR7 zener is usually swapped for a 1N4738 with a matching change to R10. Cracked header solder joints give voltages that come and go.
• Driver board. Lamps run through 74175 flip-flops and MPS-A13 transistors; sound passes through Z13 (a 7404). A whole lamp bank out, or a silent game with everything else working, points here.
• Displays. Missing segments or whole missing digits are very often nothing more than the J2/J3 edge connector.
• Slam tilt. A maladjusted or failing slam switch produces behaviour that looks exactly like a board fault, and it will throw you out of the diagnostics.

Faults owners actually report on Alien Star

This is the section worth reading twice. Everything below comes from Alien Star owner threads and from the System 80 reference documentation where it explains the mechanism.

Whole rows of switches dead — and the chip behind it

The best-documented Alien Star fault, and a genuinely useful one to know. An owner found every switch on two matrix lines dead: switch numbers 40–45 and 50–55. Gottlieb labels these lines as columns (R0–R7), so the dead lines were R5 and R6, on connector A1-J6, pins 5 and 6.

He did the sensible things first and all of them came up clean: continuity from every A1-J6 wire to its board trace, the ground mod between A3-J1 and A1-J4, the under-playfield switches and their wiring, reseating every connector in the backbox and under the playfield, and setting all the DIP switches off. None of it changed anything.

The R-lines pass through two chips on the CPU board. Z14 handles pins 14–17; Z11 was the suggested first suspect — and Z11 was indeed the fault. Replacing it, in a new socket, brought all twelve switches back. If you have a block of switches out on an Alien Star and the wiring checks out, that is where to look. A logic probe makes the call much faster than guesswork.

The game lights up but will not start a game

A lovely one, because it is not a fault at all. An owner found the machine powered on only while he held in a black plunger-style switch in the cabinet — and it would not start a game. That is the coin door interlock, which cuts power when the door is opened. The knobbed end pulls out so it locks in place; pull it out and the game stays powered with the door open. Check this before you suspect anything electronic.

Ball will not kick out, switches and solenoids look dead

This one catches people because it mimics a board failure. A machine that had sat for three months booted, took coins, made its start-up sound — and then would not serve a ball, with switches, solenoids and flippers all apparently dead. Fuses tested good. The answer was the ball trough switches: because Alien Star stages two balls for its multiball, the game is unusually sensitive to ball position in the trough and shooter lane, and a bad trough switch will hold the whole game in limbo. Removing the apron and watching what the game does with the balls pointed straight at it; a replacement trough switch fixed it. Always check the trough before condemning a CPU board on this title.

Dim, blank or garbled displays

Dim displays and a blank player-4 display are common on Alien Star, and the diagnosis has a useful rule of thumb: segment faults that appear on a pair of displays point to the CPU board (an IC or a connector), while a fault on a single display points to that display. The 7448 segment driver ICs are the parts in question.

One warning that owners pass on repeatedly, and it is worth heeding: plugging or unplugging a display with the power on can blow MPU ICs. More than one Alien Star has had its display faults created that way. Power off, always. Beyond that, clean the edge connectors with a pencil eraser and isopropyl alcohol and reseat them — in one Alien Star thread, loose connectors and broken solder joints under the playfield turned out to be behind both the display errors and several dead stand-up switches at once.

Dead flipper, general illumination dims when you press the button

A classic and a slightly alarming one. The right flipper did nothing, and the GI visibly dimmed each time the button was pressed — the sign of a coil drawing current and going nowhere useful. Several things came out of that diagnosis, and all of them apply to any System 80 machine:

• The coil had been wired to the wrong terminals. The fix was to wire the replacement (coil A-20095, per the schematic) as a mirror image of the left flipper. Always compare the two flippers before you believe either one.
• System 80 flipper circuits have no transistor and no fuse protection, so an overheated coil simply fails. There is nothing upstream to save it.
• A misgapped EOS switch will not by itself kill a flipper, but it will cook the coil until it does.
• If the plunger will not slide freely in its sleeve by hand, the coil has very likely been overheated. Check plungers and stops for wear whenever you change a coil.
• The cabinet flipper switches can foul; jumpering them is a quick way to rule them in or out.

Grounds — with one Alien Star peculiarity

Here is a detail specific to this machine and genuinely good news: on Alien Star the grounds were attached directly on the transformer panel rather than routed through a Molex connector, which removes one of the weak links that plagues other System 80 games. Do not take that as a free pass, though — an owner found the ground wire broken in several places and a corner bracket that looked to be missing its metal tab. Follow the ground path with a meter rather than assuming it is intact, and do the ground mods between CPU, Driver, power supply and sound anyway.

Playfield wear and missing inserts

Two cosmetic things to look for when you view a machine. Old, worn steel balls pit and rust the playfield, and at least one Alien Star shows exactly that damage — replace tired balls before they chew the surface. And the "STAR" inserts go missing; one owner found a previous keeper had simply written the letters on in marker, with no decals available to put it right. Neither is an electrical fault, but on a 1,065-unit game both affect what the machine is worth.

Sound that has gone quiet

The 6530 on the 6503-based System 80 sound board is both failure-prone and genuinely hard to source now. The documented protection, if yours is still alive, is a set of 1N400X diodes at the 7404 outputs plus a surge suppressor and an added ground wire. If the chip has already gone, a modern sound board is the realistic answer.

A safety check before anything else

Not Alien Star-specific, but it applies to every machine of this age and it belongs first in the list: confirm the mains cord has a proper earth and that the earth actually reaches the cabinet metalwork. A two-wire cord on a forty-year-old cabinet is a shock risk, and replacing it costs very little. Do that before you start probing live boards.

Variants, ROMs and what they mean for boards

There is no documented export-only, cocktail or conversion-kit version of Alien Star, and no second ROM revision in common circulation. What does vary from cabinet to cabinet is the generation of System 80A CPU board fitted: on the fourth-generation board, U2 and U3 are socketed and the PROM 2 socket is left unpopulated. That changes what you are looking at, not what fits. Alien Star also has the System 80A reset board, introduced with the first 80A game, and the transformer-panel grounding described above — both are standard for the title. Every board listed below covers Alien Star as built. If anything in your machine looks unusual, send us a photo of the boards and their part numbers before you order.

Replacement boards compatible with Alien Star

• GottFA80_Plus (Light) — all-in-one CPU + Driver + power supply, no sound. The simplest answer when several boards are tired at once.
• GottFA80_Plus (Full) — the same board with the sound section integrated.
• Gosof — replacement sound board, with or without speech. The answer to a dead 6530.
• Godri80 — replacement Driver board, when the lamp or solenoid drive stage has failed and the CPU is healthy.
• Lisy80 — replacement CPU board with web-based diagnostics. On a switch-matrix fault like the Z11 story above, being able to watch every switch from a browser saves a great deal of time.
• GoPOP80 — pop bumper driver board replacing the MA-922 / A-19741, for Alien Star's three pop bumpers.

All of these fit Plug & Play, run without a battery, and come with free tutorials and support. We test every board before it ships and we support it afterwards. The Lisy80 is built on LISY, a free DIY project by an independent developer — you can read about the project at lisy.dev; we supply and support ready-to-run boards based on it. Not sure what your Alien Star needs? Get in touch with a photo of your boards and we will tell you.

Step-by-step diagnosis

1. Safety first. Check that the mains cord has a working earth and that it reaches the cabinet metalwork. Replace a two-wire cord before anything else.
2. The easy wins. Is the coin door interlock plunger pulled out? Is the slam switch adjusted? Are the fuses good?
3. Powered off, look before you touch. Inspect the CPU board for a battery or a corrosion trail, including the underside. Remove the NiCd battery if it is still fitted and neutralise the residue.
4. Power supply. Measure the 5 V and confirm it reaches the MPU. Replace the orange 6800 µF filter capacitor; look at C1 and the header joints if the high-voltage fuse keeps blowing.
5. Grounds. Follow the ground path with a meter — including the transformer-panel connections and the cabinet brackets — and do the ground mods between CPU, Driver, power supply and sound.
6. Connectors. Clean the edge contacts with an eraser and isopropyl alcohol, reseat everything, and re-pin oxidised Molex connectors, the CPU↔Driver link above all. Check the under-playfield solder joints while you are there.
7. The trough. If the game will not serve a ball, pull the apron and test the trough and shooter-lane switches before suspecting a board.
8. Switch matrix. If a block of switches is dead, identify the R-line at A1-J6, check wire-to-trace continuity, then look at Z11 and Z14 on the CPU board.
9. Displays. Clean and reseat J2/J3 and test with a known-good display. Never plug or unplug a display with the power on.
10. Flippers and coils. Compare left and right wiring, check coil resistance, check that each plunger slides freely, and set the EOS gaps.
11. Final test. Start-up, credits, every coil, every lamp bank, each display, both spinners, the A-L-I-E-N targets, the lock saucer and a full multiball. If something is still wrong, contact our free support.

FAQ — Gottlieb Alien Star (1984)

How many Alien Star pinball machines were made?
1,065 units. Ownership censuses record very few surviving registered examples, so parts machines are effectively unobtainable and the original boards are worth either repairing properly or replacing with something supported.

What is a Gottlieb Alien Star worth?
Owner discussions have put a working, presentable machine in the $500–750 range, with one near-perfect example offered $1,500 and declined. Those figures date from the mid-2010s, so treat them as a reference point and check recent sales. Condition — cabinet, playfield, backglass, intact inserts — drives the price much more than rarity.

My Alien Star powers up but won't start a game.
Check the coin door interlock first: the black plunger switch in the cabinet cuts power when the door is open, and its knobbed end pulls out to lock in place. After that, check the switch matrix and the connectors — a bad contact will block start-up.

A whole block of switches is dead on my Alien Star. Where do I look?
Work out which R-line (column) the dead switches share — on one documented case, switches 40–45 and 50–55 were R5 and R6 at connector A1-J6 pins 5 and 6. Check wire-to-trace continuity, then suspect the CPU board chips in that path: Z11 and Z14. A faulty Z11 was the culprit in that case.

My Alien Star won't kick a ball out and everything looks dead.
Check the ball trough and shooter-lane switches before anything else. Because the game stages two balls for multiball, it is very sensitive to ball position there, and a single bad trough switch will make the whole machine appear dead. Remove the apron and watch what it does with the balls.

My displays are dim or one is blank.
If the fault shows on a pair of displays, suspect the CPU board (an IC such as a 7448 segment driver, or a connector). If it is on one display only, suspect that display. Clean and reseat the edge connectors first — and never plug or unplug a display with the power on, because it can blow MPU ICs.

One flipper is dead and the lights dim when I press the button.
Compare the coil wiring against the working flipper — a mis-wired coil is a documented cause on this game, and the replacement part is A-20095. Check that the plunger slides freely by hand; if it does not, the coil has been overheated. System 80 flipper circuits have no transistor or fuse protection, so a cooked coil fails outright.

Should the original battery be removed, and what fits instead?
Yes, remove it — the NiCd battery is the biggest single cause of dead System 80A CPU boards. Battery-free replacement boards keep settings and high scores in non-volatile memory. If CPU, Driver and supply are all tired, the all-in-one GottFA80_Plus is the straightforward route; if only one stage has failed, replace that one. Fitting is Plug & Play — a few minutes, no soldering.

Useful guides

• Gottlieb System 80 ground mods: why and how to do them
• A leaking battery in a pinball machine: damage and the permanent fix
• Pinball electronics explained: MPU, driver, power supply and sound
• Installing a replacement board: the Plug & Play guide
• Cleaning and maintaining a pinball machine: playfield, rubbers, contacts
• How much is my pinball machine worth? Values and estimates

See also

• Touchdown (Gottlieb, 1984) — same designer, same artist, same sound, later the same year
• Jacks To Open (Gottlieb/Mylstar, 1984)
• The Games (Gottlieb, 1984)
• El Dorado City of Gold (Gottlieb, 1984)
• Ice Fever (Gottlieb, 1985)
• Rack 'Em Up (Gottlieb/Mylstar, 1983)

Sources & further reading

• IPDB — Alien Star (#49) — photo gallery, flyer and machine record
• Pinside — Alien Star game details — release date, production run, design, art and sound credits, playfield specs
• Arcade Museum — Alien Star (Mylstar) — manufacturer attribution, weight, census rarity
• Pinside — "Alien Star: half of my switches are out, System 80A" — R5/R6 at A1-J6, switches 40–45 and 50–55, Z11 and Z14, and the fix
• Pinside — "Alien Star problems" — coin door interlock, 7448 display drivers, flipper coil A-20095, broken ground wire, playfield rust, missing STAR inserts
• Pinside — "Alien Star won't play a game" — trough switch sensitivity, dim and blank displays, connector cleaning
• Pinside — "Price check: Gottlieb Alien Star" — owner price ranges and condition factors
• PinWiki — Gottlieb System 80 — connectors and grounds, CPU chip roles, 5101 RAM, power supply components, and the Alien Star transformer-panel grounding note
• Flippers.com — tips for Gottlieb System 80 — display rejuvenation, 6530 sound-chip protection, switch-related start-up faults
• Silverball Mania — Alien Star rules — A-L-I-E-N targets, lock saucer, multiball, spinner multipliers and bonus cap
• Wikipedia — Gottlieb — Mylstar renaming, September 1984 shutdown, Premier Technology buyout
• OPDB — Open Pinball Database

Own an Alien Star? Send us a photo and we'll add it here with credit — get in touch.