Q*Bert's Quest (Gottlieb, 1983): F6 fuse, faults and System 80A boards

Is your Gottlieb Q*Bert's Quest blowing the F6 fuse, sitting there with no playfield lamps, refusing to boot or resetting mid-game? These are the classic complaints on Gottlieb System 80A, where the original CPU, Driver and power supply boards are now past forty years old. The good news: modern replacement boards — Plug & Play and battery-free — give the machine a second life, and most of the faults below are cheaper to fix than you would think.

About Q*Bert's Quest (Gottlieb, 1983)

See it: full photo gallery for Q*Bert's Quest on IPDB (#1885) · Pinside machine page and owner photos

Q*Bert's Quest reached operators in March 1983 as model 677, and only 884 were built — some of those sold as conversion kits rather than complete machines. That makes it one of the scarcer System 80A titles, and one of the few that is worth noticeably more than its siblings.

The game was designed by John Trudeau, with artwork by David Moore, Jeff Lee and Terry Doerzaph — Jeff Lee being the artist who drew the original Q*bert arcade character in the first place. Craig Beierwaltes wrote the music and shared the sound work with David Thiel, and the orange fellow's famous incomprehensible grumbling carried over from the video game.

What everybody remembers is the flipper layout. Instead of one pair at the bottom, Q*Bert's Quest has four flippers arranged as two crossed pairs — Trudeau described the idea as a battle of the flippers, left against right. The playfield is built around a big figure-eight, and the object is to light every face of a pyramid of six cubes using the rollovers and drop targets while Coily, Ugg and Wrong Way march towards it. Let a villain reach the pyramid and your cubes reset; hit a villain's targets and he backs off. Clear six pyramids and the machine gives you a free game.

It did not sell. The crossed flippers that make the game memorable also made it strange to play, and operators in 1983 wanted familiar. Worth knowing for the history: Coca-Cola had bought Columbia Pictures in June 1982, and Gottlieb was restructured as Mylstar Electronics later in 1983. Q*Bert's Quest came out before that change, so the cabinet and paperwork still read D. Gottlieb & Co., a Columbia Pictures Industries company.

• Manufacturer: D. Gottlieb & Co. (a Columbia Pictures Industries company)
• Release: March 1983 — model 677
• Production run: 884 units, including conversion kits
• Design: John Trudeau
• Art: David Moore, Jeff Lee, Terry Doerzaph
• Music: Craig Beierwaltes — Sound: David Thiel, Craig Beierwaltes
• Electronic system: Gottlieb System 80A, alphanumeric displays
• Cabinet: wide body, 4 players
• Type: solid-state, four flippers in two crossed pairs
• Theme: licensed from the Q*bert arcade game
• Variants: complete machines and conversion kits (playfield and backglass only)

On rarity and money: the KLOV/Arcade Museum census scores it 2 out of 100 for rarity, with only a handful of machines registered to active collectors. Pinside currently puts the value in the $9,250–$10,750 band, with a median sale price around $10,000 over the last four years, and lists 27 Pinside owners against 110 people with it on a wishlist. Prices move, so treat those as a direction of travel rather than a quote.

One note on the conversion kits

Because some of the 884 were sold as kits — playfield and backglass only, dropped into an existing cabinet — the machine in front of you may not have Q*Bert's Quest boards in it at all. Before ordering anything, open the backbox and read the part numbers off the boards you actually have rather than trusting the game on the playfield. If the numbers do not match what you expect, send us the references and we will work out what you are looking at.

Common faults on System 80A

Across the whole System 80 and 80A family the recurring faults come from age, and they come in a predictable order.

The NiCd battery on the CPU board is first and worst. It leaks, the electrolyte creeps along the traces and under the IC sockets, and it keeps eating copper for years after the battery itself has gone flat. Deal with this before anything else — if there is still a battery on your board, take it off.

Then the logic: tired 6532 RIOT chips, dried-out capacitors, and no boot at all. On early System 80 CPU boards there is also a designed-in timing error on access to the 5101 CMOS RAM that stops the last memory location being written; the standard cure is a modification at Z36 (a 4069) plus a 3K3 pull-up. Separately, the notorious startup thunk traces back to SN74175N "clear" chips whose pin 1 was tied straight to +5 V instead of going through a proper reset circuit.

After that it is grounds and connectors. System 80A machines were built with grounds that return through the board edges, and forty years of oxide turns that into random resets, phantom switch hits and displays that come and go. The ground mods are not optional on a machine you want to rely on: a jumper from the CPU board's ground hole (the one at the 3 o'clock position) to cabinet ground, a jumper from the power supply ground line to the supply frame, the negative lead of C1 bonded to the regulator frame, and the regulator frame taken to cabinet ground via the headboard lock wire.

Finally the odds and ends that masquerade as board failures: a slam switch that trips on its own and gives you rolling displays and no game start; a coin door lockout loop jammed into a coin blade switch, which locks the whole game up; the orange capacitor in the bottom of the cabinet, which is worth replacing before you troubleshoot anything else; and displays with missing segments that are very often nothing more than the J2/J3 connectors.

Faults specific to Q*Bert's Quest

This is where owner reports earn their keep. The following come up again and again on Pinside, not as one-off oddities.

The F6 fuse blows and every controlled lamp goes out

This is the signature Q*Bert's Quest fault. The 8 A F6 fuse lets go, all of the switched playfield lamps die, and the general illumination carries on as though nothing happened — which is exactly what confuses people, because the game still lights up. Owners who dropped in a 7 A fuse to see what would happen watched it blow within seconds.

It is almost never the board. It is a short in a lamp socket: the socket's contact tabs bent far enough to touch each other or the socket body, or a scrap of metal debris sitting inside a socket. Work through the sockets with the glass off and the power off, looking for tabs out of position and anything metallic that should not be there. Reposition, clean, resolder. Check F10 at the same time, because it frequently goes with F6.

Only once the short is gone should you suspect the drive stage. If a lamp circuit stays dead with good fuses and no short, the output on the Driver board is the next thing to test — and that is what a Godri80 or an all-in-one GottFA80_Plus replaces.

Lamps that will not stay on through boot-up

A related complaint: lamps that come up and then drop out as the game finishes its start-up sequence. On System 80A this usually points back to the same lamp circuit and its grounds rather than to the CPU. Do the ground mods first; it resolves a surprising share of "intermittent lamp" reports.

Pop bumper blowing a 2 A fuse

Classic System 80 behaviour and very common on these games. Replace the 2 A fuse, get a few hits, blow it again. The culprit is normally the driver transistor on the pop bumper driver board, not the coil or the switch. The quickest test costs nothing: swap the two pop bumper boards over and see whether the fault follows the board or stays with the bumper. If it follows the board, you have your answer — and the GoPOP80 drops straight in.

Dead rollover switches that wreck the game

Owners report rollovers that stop registering, and on this machine that matters more than usual: the rollovers are how you advance the pyramid, so two dead ones turn the game into a frustrating mess even though everything else works. Clean and gap the switch blades, and check continuity all the way back to the connector before you blame the CPU.

Split speaker cones and muddy voice

Thirty-plus years is enough to tear a paper cone even on a speaker that is still firmly mounted. Owners who replaced the originals with modern speakers report a clear improvement in both the background effects and Q*bert's gibberish. If your sounds are present but mushy, listen to the speaker before you condemn the sound board.

Dark corners and broken plastics

Two cosmetic complaints worth planning for. The playfield has dark patches around the villain zones (top-left and mid-right) and in the shooter lane, which LEDs even out nicely. And the playfield plastics break — the bottom-right plastic in particular is very hard to find as NOS, so if you see one, buy it.

Replacement boards compatible with Q*Bert's Quest

Q*Bert's Quest is a standard System 80A game, so the System 80/80A/80B board range applies. We test every board before it ships and support it afterwards, and none of them needs a battery.

• GottFA80_Plus (Light) — all-in-one CPU + Driver + power supply board, without sound.
• GottFA80_Plus (Full) — the same with integrated sound.
• Gosof — replacement sound board, available with or without speech. Check which sound configuration your game actually has before choosing.
• Godri80 — replacement Driver board; this is the one for dead lamp or coil outputs.
• Lisy80 — CPU board with web diagnostics, which makes switch and lamp testing far quicker. Lisy is an independent developer's free DIY project; see lisy.dev.
• GoPOP80 — pop bumper driver board (replaces MA-922 / A-19741).

Plug & Play installation, battery-free, free tutorials and support. If your game came from a conversion kit, or you are not sure what is in the backbox, contact us with the board references first.

Step-by-step diagnosis

1. Power off, look. Inspect the CPU board for battery residue and green corrosion, especially around the IC sockets. Remove the NiCd battery if it is still fitted.
2. Fuses. Check F6 (8 A) and F10. If F6 is open and your general illumination works but the playfield lamps do not, go to the lamp sockets before you go to the boards.
3. Lamp sockets. Glass off, power off: look for contact tabs touching each other or the socket body, and for metal debris inside sockets.
4. Power supply. Measure the 5 V and confirm it actually reaches the CPU board. Reflow the regulator and Q1 joints if the voltage sags under load.
5. Grounds. Do the ground mods between CPU, Driver, power supply and sound. This is the single highest-value hour you can spend on a System 80A.
6. Connectors. Re-pin oxidised Molex connectors, the CPU-to-Driver link above all.
7. Displays. Never plug or unplug a display with the power on. Test with a known-good display before buying anything.
8. Pop bumpers. If a 2 A fuse keeps blowing, swap the two pop bumper boards and see whether the fault moves with the board.
9. Final test. Start-up, credits, coils, lamps, displays, rollovers. If something still will not behave, our support is free.

FAQ — Q*Bert's Quest (Gottlieb, 1983)

The F6 fuse blows and I have no playfield lamps. What is it?
Nine times out of ten it is a short in a lamp socket — contact tabs touching each other or the socket body, or metal debris inside a socket. Fit the correct 8 A fuse, find the short, and check F10 while you are in there. Owners who substituted a 7 A fuse reported it blowing within seconds, which tells you the short is real and not a marginal fuse.

How many Q*Bert's Quest machines were made?
884, in March 1983, as model 677 — and some of those were conversion kits rather than complete machines. It is one of the rarer System 80A titles.

My Q*Bert's Quest will not start at all.
Start with the CPU board battery and the corrosion around it; on a 40-year-old System 80A board that is the most likely cause by a wide margin. Then check that 5 V reaches the board, and do the ground mods. A GottFA80_Plus or Lisy80 removes the weak point permanently.

Why does my Q*Bert's Quest have four flippers?
By design. John Trudeau laid the game out with two crossed pairs of flippers — his "battle of the flippers", left against right — around a figure-eight playfield. Nothing is broken; it is meant to look like that.

What is a Q*Bert's Quest worth?
Pinside currently estimates $9,250–$10,750, with a median sale price around $10,000 over the past four years. Condition and completeness move that a long way, and the market shifts, so use it as a guide rather than a valuation.

My pop bumper keeps blowing a 2 A fuse.
Usually the driver transistor on the pop bumper driver board rather than the coil. Swap the two pop bumper boards over: if the fault follows the board, replace or rebuild it — the GoPOP80 is a direct fit for MA-922 / A-19741.

Should I keep the original battery?
No. Take it off and keep it off. Our boards run without one, which removes the number-one cause of System 80A corrosion.

Does a battery-free board keep the settings and high scores?
Yes. Modern replacement boards use non-volatile memory: no battery, no corrosion, and the settings stay put when the machine is switched off.

Useful guides

• GottFA80_Plus: the all-in-one board for Gottlieb System 80/80A/80B
• GoPOP80: plug-and-play pop bumper driver board (replaces MA-922 / A-19741)
• Repairing a System 80 Driver board: replacing a burnt MOSFET and decoder
• Repair or replace a pinball circuit board: which should you choose?
• How much is my pinball machine worth? Values and estimates by model
• Understanding the Lisy80 board in five minutes

See also

• Krull (Gottlieb, 1983)
• Super Orbit (Gottlieb, 1983)
• Goin' Nuts (Gottlieb, 1983)
• Amazon Hunt (Gottlieb, 1983)
• Royal Flush Deluxe (Gottlieb, 1983)
• Rack 'Em Up (Gottlieb, 1983)
• Ready Aim Fire! (Gottlieb, 1983)

Sources & further reading

• IPDB — Q*Bert's Quest (#1885)
• Pinside — Q*Bert's Quest: credits, production, market value
• Pinside thread — "Q-Bert F6 fuse blow / no lamps"
• Pinside thread — Q*Bert's Quest owners, restoration and gameplay
• Pinside thread — Gottlieb System 80 pop bumper blowing a fuse
• Flippers.com — tips for the Gottlieb System 80 series (ground mods, 5101 RAM, SN74175N)
• Flippers.be — Q*Bert's Quest review and conversion-kit note
• Kineticist — Q*Bert's Quest: production, model number, credits
• Arcade Museum (KLOV) — Q*Bert's Quest census and rarity
• Kineticist — Mylstar Electronics: Gottlieb's forgotten year
• TV Tropes — Q*Bert's Quest: layout, rules and design intent
• OPDB — Open Pinball Database

Own a Q*Bert's Quest? Send us a photo and we'll add it here with credit — get in touch.