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Grandstand Firefox F-7

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Grandstand Firefox F-7
Grandstand Firefox F-7 Instructions cover
The Firefox F-7 as drawn on page 1 of Grandstand's instruction booklet (1983). No freely licensed photograph has been found.
Specifications
ManufacturerEpoch (made in Japan) for Grandstand (Adam Imports Ltd, Harrogate)[1]
TypeTabletop electronic game
Released1983[1][2][3]
CPUNEC μPD7528C 4-bit microcontroller, labelled D7528C 011, with a second NEC chip labelled D1771C 011 (from an owner's schematic)[4]
Memory—
Storage—
DisplayVacuum fluorescent display (NEC FIP series, labelled 7AM33T on an owner's schematic), mounted above the main board[5][3][4]
SoundTwo piezo speakers, each with its own on/off switch: music on the left, sound effects on the right[1][6]
InputJoystick (left, right, and up or down for high or low speed), firing button, start and skill level select buttons, power switch[1]
PowerFour C (Duracell MN1400) cells, or the Grandstand Universal Mains Adaptor set to negative[1]
OS / Firmware—
Model no.11279[7]

Grandstand Firefox F-7 is a battery-powered tabletop space game with a vacuum fluorescent display (VFD), made in Japan by Epoch and sold in the UK by Grandstand from 1983.[1][2] It is Epoch's Astro Thunder 7, which Epoch also sold as Galaga X6 and Radio Shack as Astro Thunder.[7][6] The player flies a spaceship through six phases of combat with a limited energy supply, ending in an attack on an enemy energy base, and the game has two speakers with a switch for each.[1] It is one of the later Epoch games in Grandstand's range and shares its battery cover with Astro Wars, Scramble and Star Force.[8]

History

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The Grandstand booklet is dated 1983 and gives the distributor as Adam Imports Ltd, a member of the Adam Leisure Group PLC, Ripon Way, Harrogate; the game was made in Japan.[1] The V&A holds an example dated 1983, made in Japan, which it describes as battery operated with a "speaker system", and the Centre for Computing History and the Handheld Museum also give 1983.[2][3][7] The box text recorded by the Centre for Computing History advertises an "exciting 3D effect", "sound effects from twin speakers" and "4th generation technology".[3]

The same game was sold as Epoch's Astro Thunder 7 and Galaga X6, and in the USA by Radio Shack as Astro Thunder (catalogue number 60-2197), which the Handheld Museum dates to 1986.[7][9] Radio Shack's manual describes the same controls, display and 1,000-point maximum as the Grandstand booklet, though its story is different: an alien fortress with a "megatron cannon" in place of the enemy energy base.[6] A dealer's museum page says the Grandstand name was inspired by the Clint Eastwood film Firefox; the booklet does not mention the film.[10]

Hardware

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Firefox F-7 hardware
Part Detail
Microcontroller NEC D7528C, labelled D7528C 011
Second chip NEC, labelled D1771C 011; drives the large speaker
Display VFD on a bracket above the main board, labelled 7AM33T on the schematic; the board silkscreen reads "FIP"
Display supply Transformer TX-30 driven by a D882 power transistor (S04), whose base is driven by a C945 (S03)
Control board Joystick, select, start and fire contacts, and the power and two speaker switches; joined to the main board by a ten-way cable
Sound Two piezo speakers, small and large, each with an on/off switch
Power Four C cells (6 V), or an adaptor through a switched DC socket

Chips, display label, power section and wiring from a schematic drawn in 2022 by an owner, Philip Bryden, from his own boards, which he describes as a first attempt;[4] board layout from the Handheld Museum's photograph of an opened game;[5] sound and power from the Grandstand booklet and Radio Shack's manual.[1][6] The second chip has been traced to the large speaker by Bryden and was thought by Retro Tech Repair to produce the more complex sounds.[11][12] Firefox F-7 is not emulated in MAME.

Like the other Epoch tabletop games, it takes four C cells in the battery compartment shared with Astro Wars, Scramble and Star Force; a 3D-printed replacement cover is made for all four, and Wikipedia lists the same compartment for Firefox F-7, Astro Thunder and Astro Thunder 7.[8][13] Its microcontroller differs from the μPD553 used in Astro Wars and Scramble, but the display supply follows the same pattern of a D882 power transistor driving a small transformer.[4]

The game

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The player's spaceship moves left and right along the bottom of the display and fires a laser upwards; a second shot can be fired before the first leaves the display. Enemy fighters can only be hit while they are in the "ionosphere", the band marked by arrows at each side. The player starts with 20 energy units, shown by the F (full) and E (empty) indicator and a column of boxes, and loses one for each collision with a wall of radiation or an asteroid, each hit by an enemy beam gun, a set number of fighters allowed through to the bottom of the display, and, at level 3, every eight shots fired. The game ends when the energy runs out.[1]

Pushing the joystick up selects high speed (H) and down selects low speed (L) for a few seconds. A fighter destroyed at normal speed scores 2 points, at high speed 5 and at low speed 1. Three skill levels set the pace.[1]

There are six phases:[1]

  1. Fighters attack in zigzags while the ship avoids walls of radiation; 60 seconds.
  2. Asteroids fall in groups of three; 60 seconds.
  3. Fighters fire beam guns. The phase lasts at least 70 seconds and ends once eight fighters have been hit.
  4. Fighters are launched in threes from enemy launching pads; again eight hits are needed.
  5. The walls of radiation return as broad and narrow passages; eight hits.
  6. The enemy energy base appears at the top, armed with a "super blaster gun", and the score positions show a time limit counting down from 300. Eight hits on the base within the limit earn nine extra energy units; the phase cannot be left without eight hits. Play then returns to phase 1.

A perfect game is 1,000 points, shown as "H" "H" with a victory song.[1]

Batteries and power

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Grandstand recommends four Duracell MN1400 (C) cells and says the game will not work properly on weak batteries; if it malfunctions or the display is erratic, check or replace them. Switch off after play and take the cells out if the game is not used for long periods.[1]

For mains use the booklet names the Grandstand Universal Mains Adaptor, not included, with the polarity switch set to negative; it gives no voltage.[1] Radio Shack's manual for the same game asks for its 273-1650 adaptor on the 6 V range with the centre tip set negative, and lists 270-7001 for 240 V in the UK.[6] Use 6 V with the centre negative, and measure the plug before connecting it. See Grandstand Firefox F-7 General Maintenance#DC socket and adaptor and Grandstand Universal Mains Adaptor.

Repair

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Firefox F-7 has its own repair guides:

Most dead Firefox F-7s that owners have repaired on video had a failed D882 power transistor.[15][12][11] Other faults were oxidised battery and DC socket contacts, a crack at a screw post that broke a track on the board, a worn carbon pad under the firing button, a broken ten-way cable between the boards, and a solder bridge that made the sound chip run hot.[16][17][11][12] Two of Philip Bryden's games had faulty microcontrollers, proved by swapping the chips, and could not be repaired.[18] Before treating a game as silent, check both speaker switches.[6][1] Radio Shack's manual also warns that even leak-proof cells can leak and ruin the game, and asks for it to be kept dry, out of heat and away from harsh cleaning chemicals.[6]

Documentation

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References

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  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 Grandstand, Firefox F-7 instruction booklet (Adam Imports Ltd, Ripon Way, Harrogate; © 1983; made in Japan), hosted here as File:Grandstand Firefox F-7 Instructions.pdf (PDF page numbers): p. 1, control drawing (left and right speaker switches) and batteries box (four Duracell MN1400; Universal Mains Adaptor on negative polarity; weak-battery warning; care note); pp. 2-4, controls, three skill levels, high and low speed and the display; pp. 5-7, the five phases of combat and the sixth against the enemy base; p. 8, scoring and a perfect game of 1,000 points.
  2. ↑ 2.0 2.1 2.2 Victoria and Albert Museum, O27498, "firefox f-7", "Grandstand electronic game" (retrieved 2026-10-18): table game, 1983, made in Japan, "battery operated, hand held; speaker system".
  3. ↑ 3.0 3.1 3.2 3.3 Centre for Computing History, "Grandstand Firefox F-7", CH41380 (retrieved 2026-10-18): introduced 1983; vacuum-fluorescent display; box text "Exciting 3D effect", "Sound effects from twin speakers", "4th generation technology", three skill levels, joystick fighter control, sound off switch, high and low speed control.
  4. ↑ 4.0 4.1 4.2 4.3 Philip Bryden, "Grandstand Firefox F7" schematic, three sheets ("Power rail", "Data", "Control Board"), KiCad 6, revision 1, 8 June 2022, PDF on MEGA linked from his video (retrieved 2026-10-18). Drawn by the owner from his own boards and described by him as a first attempt that may need revision. It shows the microcontroller labelled D7528C 011 and a second chip labelled D1771C 011; the display labelled 7AM33T, with its filament on display pins 1 and 2 and 30 and 31; a ten-pin transformer TX-30 driven by transistor S04 (882), whose base is driven by S03 (C945); diodes S05 to S12; capacitors C01 to C15 without values, of which C01 to C05 are drawn as polarised (electrolytic) parts; a 5 MHz resonator X01 (FCR5.0M); and a ten-way cable L01 to the control board, carrying 6 V DC on pin 4. Control board: the power switch; up, down, left and right joystick contacts; select, start and fire; a "sound L" switch for the small piezo speaker and a "sound R" switch for the large one; and a switched DC socket whose centre pin is the negative (ground) side.
  5. ↑ 5.0 5.1 Handheld Museum, "Guts" (retrieved 2026-10-18): photographs of opened Grandstand Astro Wars (main board 19096 standing in the hood with the display; control board 96062 marked START, SELECT and FIRE; joystick on its own small board), The Big Game Soccer (main board in the centre with the display; battery holder along the top; DC socket at the top right; a control board each side) and Firefox F-7 (display on a bracket above the main board, with "FIP" and an illegible number in the silkscreen beside it; two chips on the main board, neither legible; control board with round contact pads below).
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 Radio Shack, Astro Thunder owner's manual (custom manufactured for Radio Shack; printed in Japan), hosted here as File:Radio Shack Astro Thunder Manual.pdf. The same game as the Firefox F-7. p. 1: four C cells, or Radio Shack's 273-1650 adapter on its 6 V range with the centre tip set negative (270-7001 for 240 V in the UK); check the batteries if the game malfunctions or the display is erratic; "Even leakproof type batteries can leak damaging chemicals, which will ruin your unit permanently". p. 2: left and right sound switches. p. 7: maintenance (keep dry, no heat, no harsh chemicals, fresh alkaline cells).
  7. ↑ 7.0 7.1 7.2 7.3 Handheld Museum, "Grandstand Firefox F-7" (retrieved 2026-10-18): 1983, VFD, four C cells, model 11279; the same game as Epoch Astro Thunder 7, Epoch Galaga X6 and Radio Shack Astro Thunder.
  8. ↑ 8.0 8.1 YoxxxoY Jorge, "Battery cover Epoch electronic games", Thingiverse 3399673 (2019), archived on the Internet Archive (retrieved 2026-10-18). 3D-printable battery cover; the designer lists Astro Thunder, Astro Thunder 7, Firefox F-7, Astro Command, Astro Wars, Space Defender, Galaxy II, Star Force and Scramble. CC BY 4.0.
  9. ↑ Handheld Museum, "Tandy Astro Thunder" (retrieved 2026-10-18): 1986, VFD, four C cells, model 60-2197, original price $39.95; lists the Grandstand Firefox F-7, Epoch Astro Thunder 7, Epoch Galaga X6 and Radio Shack Astro Thunder as the same game. (It calls the Tandy version "licensed from Grandstand"; Grandstand did not make games.)
  10. ↑ Retro Games (Chillout Games), "Grandstand" museum page (retrieved 2026-10-18). Dealer's list of Grandstand tabletop games with years: Scramble 1982, "licensed from Epoch", perfect game 3,000 points; Firefox F-7 1983, six phases, three skill levels, twin speakers, perfect game 1,000 points; Star Force 1984, "the last in the arcade series".
  11. ↑ 11.0 11.1 11.2 Philip Bryden, "Grandstand Firefox F-7 | No Power | Faulty Audio | Fiasco", YouTube, 29 May 2022 (transcript read 2026-10-18). A dead Firefox F-7 drawing no current; a centre-negative Mega Drive power lead fits the socket; the case marking calls for negative polarity; six screws (0:10-3:51). The battery terminal wires, marked positive and negative, have to be unsoldered to take the board out (6:41). 6 V reached pin 4 of the ribbon cable and the transformer; the D882 power transistor had died; its base is driven by a small C945 (8:56-11:37). A salvaged substitute fitted the wrong way round drew 0.8 A and burnt his finger (12:50-17:41). Lifting every diode changed nothing (21:02-22:03). Removing the capacitors did not reduce the current, though some measured out of tolerance (23:31-24:01). A new D882 failed again and a second one was fitted; the game then drew about 300-400 mA and the display worked (24:10-28:22). The transformer has ten pins and the board carries an arrow to align it; he found no fault in it (27:29-28:01). The getter was black, "a good sign" (25:31). There is no volume control (25:22). Intermittent sound and a joystick that would not go right were caused by the ten-way ribbon cable inside, which he replaced with wires from an IDE cable (28:35-40:12). The in-game sound effects were still missing at the end; he suspected the sound chip or X01 (40:35-41:03).
  12. ↑ 12.0 12.1 12.2 Retro Tech Repair, "Fixing a Broken Astro Thunder Handheld - What's Wrong With It?", YouTube, 1 October 2021 (transcript read 2026-10-18; the game is a Grandstand Firefox F-7). The joystick knob can be removed, or lifted and turned, to free the top cover (2:08-2:33). The Fresnel lens is built into the display window (2:41). The battery tabs are soldered and must be unsoldered to free the board (5:04). The getter in the display should be black; on a spare board it had turned white and the tube's vacuum port had been knocked off (6:05-6:44). The D882 tested as "two resistors"; a salvaged one was also bad, and a second worked (7:36-9:14). The keypad must be in place for testing (8:56). The sound was then quiet: cleaning had taken the carbon off the fire pad, so he swapped it with the select pad; the speaker's solder joints and foam pad were renewed (9:31-13:51). The sound chip ran very hot and the current was high; a chip from a spare board behaved the same, and recapping the two supply capacitors changed nothing; the cause was a solder bridge between two tracks on a badly soldered connector, one of them to the sounder (14:24-22:16). The smaller speaker is driven by the main processor and the larger by the second chip, for the more complex sounds (5:28-5:50). Remanufactured moulded battery doors for Astro Wars and Firefox F-7 are "not a perfect fit" but close (22:47-23:02).
  13. ↑ Wikipedia, "Astro Wars" (revision of 1 June 2025). Hardware section, without references: the D882 power transistor "is known to fail frequently", the S06 zener less often; the display has "a glass nipple which can easily be fractured"; isopropyl alcohol for contacts; the same battery compartment on Astro Thunder, Astro Thunder 7, Firefox F-7, Astro Command, Space Defender and Scramble. The article also calls the game "made in Great Britain", which the Grandstand leaflet contradicts.
  14. ↑ analo9, "1983 에포크 아스트로 썬더7 (EPOCH Astro Thunder7, FirefoxF7 repair)", YouTube, 2 November 2023 (frames from 7:36 to 7:54 looked at at full size, 2026-10-19). An Epoch Astro Thunder 7, whose export version the description names as the Grandstand Firefox F7, on main board 96261: five grey NTK electrolytics removed and shown beside the board, marked 220 μF 16 V (two), 22 μF 50 V and 3.3 μF 50 V, the fifth turned away; replaced with Nichicon parts.
  15. ↑ Retro Tech Repair, "This Vintage VFD Game Has a Hidden Problem", YouTube, 13 August 2019 (transcript read 2026-10-18). A dead Grandstand Firefox F-7 with some battery corrosion, two case screws missing and others replaced with wood screws (1:22-2:56). Peel the sticker off the joystick and undo the Phillips screw to lift the knob off; a vinyl overlay covers the board; the control panel unclips; two sounders, where Astro Wars has one (3:09-4:47). The power switch is in the middle of the board and was bridged with a wire for testing (5:38). The D882 read short between pins 1 and 3; a used D882 from another game cured it (6:26-8:47).
  16. ↑ retro_restos, "Grandstand Firefox F-7 Repair. Vintage Electronic Game Repair 1980's Retro", YouTube, 30 May 2023 (transcript read 2026-10-18). A boxed game with a printed notice explaining that the left and right speakers make different sounds, because owners thought their games faulty (0:58-1:13). Missing battery cover; DC inlet 6 V, negative pin (2:15-2:36). Dead on cells and adaptor: contact cleaner and wiggling the DC socket brought it to life, and contact cleaner and very fine abrasive paper on the battery contacts cleared "a very thin film of oxidation" (3:37-6:23). The ship would not move right; cleaning the joystick contacts and pads with isopropyl alcohol cured it (7:25-19:14). Six screws in the base and a tiny screw in the joystick; an earlier opener had not screwed the screen back properly; a broken stud was plastic-welded (8:58-11:17). Do not polish the printed and painted areas (22:53-23:20). The battery cover is shared by "three or four different models" (25:51). The flicker seen on camera is not visible in person (6:56).
  17. ↑ StezStix Fix?, "I Paid £30 For an 'UNTESTED' Grandstand FIREFOX F-7", YouTube, 23 April 2022 (transcript read 2026-10-18). A boxed Firefox F-7 with 6 V at the batteries but no power; two case screws missing and a loose broken post rattling inside (0:18-2:47). A crack at a screw post had cracked the board and broken a track; a wire jumper and reflowing some poor joints restored power (2:15-8:21). The board cannot come out without desoldering; he photographed the wiring first (3:20-3:30). The fire button's carbon pad measured about 240 kΩ against 15-45 kΩ for the other pads; copper tape on the pad worked, and he then swapped the fire and select pads (10:05-11:55). The sound is very loud (8:25).
  18. ↑ Philip Bryden, "Grandstand Firefox F-7 | Astro Thunder | Schematic Download Available", YouTube, 11 June 2022 (description read 2026-10-18; transcript not available): both of his Firefox F-7s had faulty microcontrollers, which he proved by swapping the chips between them; with no replacement chips they could not be repaired; he drew a schematic of the game in KiCad, linked from the description.


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