Grandstand Scramble General Maintenance
Care, cleaning and opening of the Grandstand Scramble, the horizontally scrolling space game with a vacuum fluorescent display (VFD) that Epoch made in Japan and Grandstand sold in the UK from 1982. It is Epoch's Astro Command, which Tandy and Radio Shack also sold in the USA under that name, so repair accounts for all three apply.[1][2] No service manual or schematic has been found for any of them, and no scan of Grandstand's leaflet is online. What follows draws on the base label and leaflet as shown in an owner's video, MAME's notes, a Handheld Museum forum thread from 2016 and repair videos from seven channels published between 2018 and 2025. Faults are on Grandstand Scramble Troubleshooting Guide.
The Scramble at a glance
[edit | edit source]| Part | Detail |
|---|---|
| Case | A gloss black body and a painted silver section; a bezel inside the top cover clips in place[3][4] |
| Fixings | Six screws in the base, plus a small screw under a sticker on top of the joystick knob[4][5][6] |
| Cells | Four C cells: HP11 zinc-carbon or MN1400 alkaline[7] |
| Adaptor | Grandstand Universal Mains Adaptor set to negative; no voltage printed. Repairers use 6 V DC, centre negative[7][8] |
| DC socket | On the right-hand side; the battery positive runs through a contact inside it[9][5] |
| Boards | 96111 and 96112; the main board sits on a bracket held by two screws[1][4] |
| Microcontroller | NEC μPD553C, labelled D553C 202[1] |
| Power section | D882 power transistor driving a round transformer; C2785 small transistors[10][4] |
| Display | NEC FIP9AM20T no. 42-42, cyan and red, behind a magnifying lens and a transparent printed space scene[1][10] |
| Controls | Four-way joystick, POWER slide switch, SELECT, START, MISSILE and BOMB[1][9][4] |
| Sound | Piezo speaker on two thin wires[4] |
Before you start
[edit | edit source]- Take the cells out. Repairers test these games from a bench supply set to about 6 V.[11][8]
- The sticker or cap over the joystick screw is easily damaged and hard to replace. Keep it safe.[11][5]
- The control board's flat cable to the main board frays if the boards are turned over repeatedly; one owner broke several of its wires that way.[10]
- Cover the display while working near it. It is a glass tube.[8]
Opening the case
[edit | edit source]The order below follows Rust Belt Vintage Toy Repair's account of a Radio Shack Astro Command, which agrees with the Grandstand Scrambles opened by retro_restos and Kip Hakes.[4][5][6]
- Remove the cells.
- Take off the joystick knob. Peel back the small sticker or cap on its top; on some games it is glued, and a little acetone or alcohol softens the glue. Undo the small screw beneath and lift the knob off the stalk, which then passes through the top cover.[4][5][12]
- Remove the six screws in the base and lift the top cover away.[4][5]
- Unclip the bezel. Two screws hold the main board's bracket.[4]
- Keep the piezo speaker's wires slack: they break easily.[4]
- The battery contacts are wired to the board. Unsolder them to take the contacts out for cleaning, noting which wire goes where.[4]
- Three screws free the control board. It is joined to the main board by a flat cable; handle it gently.[4][12][10]
- The joystick contacts sit under a cover on the joystick mount: three screws in Rust Belt's count, four in Vintage Gaming Memories'.[4][12]
Reassembly. Clip the bezel back, fit the top cover with its six screws, then refit the knob, its screw and the sticker or cap, gluing the cap if it was glued.[4][5] The screws go into plastic posts. Turn each one backwards until it drops into the existing thread before tightening it, so that it does not cut a new thread and strip the post.[11]
Cleaning
[edit | edit source]- The display window and the transparent space-scene film behind it gather dust inside; both can be cleaned once the case is open.[12]
- The screen scratches easily: one Scramble's was scratched by an adaptor packed in its box.[7]
- The screen surround is a printed sticker. On one game its clear top layer was peeling; the owner removed that layer and lacquered the sticker, a step he warns might react with the print.[3]
- The white lettering on the control panel wears off with use. Owners have redrawn it with a white paint marker.[6][3][12]
- For the plastics, owners have used glass cleaner on the screen and plastic polish on the case; one refinished the gloss black section with fine abrasive pads before polishing.[8][12][3]
- A box kept on a sunny shelf fades badly.[7]
Batteries and battery contacts
[edit | edit source]The base label calls for four HP11 C cells, and the leaflet names HP11 zinc-carbon or MN1400 alkaline types.[7]
- Corrosion in the battery box is common. One Epoch Astro Command's contacts had rusted and had to be cleaned and filed; Retro Tech Repair replaced a corroded set with contacts from a second Scramble.[10][11]
- Polishing the contacts can be enough to make a game run on batteries again.[8]
- Without the cover, the cells push themselves out; retro_restos remarks how often covers are lost for that reason.[8] The 3D-printable Epoch cover is listed by its designer as fitting Scramble and Astro Command.[13]
DC socket and adaptor
[edit | edit source]Grandstand's base label asks for the Grandstand Universal Mains Adaptor with negative polarity, and the leaflet gives no voltage.[7] The repairers who power Scrambles from a supply use 6 V DC with the centre negative.[8][5] One Scramble that reached a repairer came with a 9 V adaptor with a positive centre that read nearly 13 V off load; check any adaptor before plugging it in.[14] See Grandstand Universal Mains Adaptor.
The socket is wired so that the negative lead runs straight through while the battery positive passes through a contact inside it; inserting a plug opens that contact and cuts the cells out of circuit.[5][6] With no plug in, the cells should have continuity through the socket to the board; with a plug in, they should not.[8] A corroded socket made one game cut out on the adaptor and fail on batteries. It was replaced with a new-old-stock socket with three pins, one negative and two positive.[5]
Controls
[edit | edit source]Joystick
[edit | edit source]The joystick moves in four directions. On an Astro Command whose stick no longer returned to centre, cleaning the mechanism and adding a dry lubricant cured it; Rust Belt cleaned the joystick contacts with denatured alcohol.[12][4]
Buttons and power switch
[edit | edit source]- MISSILE fires horizontally and BOMB drops vertically.[4] Each has a spring underneath; contact cleaner on those springs improved one game's buttons.[12]
- SELECT and START needed only cleaning on the same game.[12]
- The POWER slide switch can stick where it rubs on the case; polishing the rubbing surfaces freed one.[12]
Display, lens and artwork
[edit | edit source]The VFD is an NEC FIP9AM20T with nine grids, glowing cyan and red. A colour overlay tints the right three columns yellow and six columns of the bottom row pink.[1] The background scenery is printed, on a transparent film and a landscape laminate behind and beneath the window, and a magnifying lens enlarges the display.[10][15][12]
- Kip Hakes checks the getter inside the tube: black, he says, means the vacuum is intact, while a white powdery deposit is bad.[6]
- A broken tube cannot be repaired; a replacement must come from another Scramble or Astro Command.[1]
What wears, and what to check
[edit | edit source]| Part | What happens | Check |
|---|---|---|
| Power transistor (D882) | Fails, leaving the game dead | Grandstand Scramble Troubleshooting Guide[8][6] |
| DC socket | Corrodes; cuts out on the adaptor or blocks the batteries | Continuity with no plug in[5] |
| Battery contacts | Rust and corrosion | Clean, polish or replace[10][11] |
| Joystick | Stops returning to centre; dirty contacts | Clean, dry lubricant[12] |
| Control board cable | Frays when the boards are flexed | Handle gently[10] |
| Joystick sticker or cap | Lost or torn when the knob comes off | Lift carefully; re-glue[11][5] |
| Panel lettering, screen sticker | Wear and peel | Paint marker; lacquer with care[3] |
Storage
[edit | edit source]- Take the cells out, and keep the game dry: rusted battery contacts were the first fault on the Astro Command in the Handheld Museum thread.[10]
- Keep the box and the game out of the sun, and do not pack anything hard against the screen.[7]
Preventive maintenance checklist
[edit | edit source]- Check the battery contacts for corrosion and polish them.
- Measure any adaptor: 6 V DC, centre negative.
- With no plug in, check continuity from the battery box through the DC socket.
- Clean the joystick, the button springs and the POWER switch.
- While the case is open, look at the control board's flat cable and the piezo wires.
- Refit the joystick cap or sticker carefully.
Related pages
[edit | edit source]- Grandstand Scramble
- Grandstand Scramble Troubleshooting Guide
- Grandstand Astro Wars General Maintenance: the Epoch game closest to Scramble in its electronics.
- Grandstand Universal Mains Adaptor
- Battery Explosion, Capacitor or Corrosion Damage
- Recommended Tools
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 MAME source, hh_ucom4.cpp at commit d404316 (retrieved 2026-10-18). Driver notes for Epoch Astro Command: PCB labels 96111 and 96112; NEC μPD553C microcontroller labelled D553C 202, 1-bit sound; cyan and red VFD NEC FIP9AM20T no. 42-42 (nine grids); colour overlay with the right three columns yellow and six columns of the bottom row pink; released in Japan by Epoch, in the USA by Tandy and in the UK by Grandstand as Scramble. The program in MAME was dumped from a Tandy Astro Command. The input map has a four-way joystick, SELECT, START, MISSILE and BOMB.
- ↑ Handheld Museum, "Grandstand Scramble" (retrieved 2026-10-18): 1982, VFD, four C cells; licensed from Epoch (Astro Command); found with the word "Scramble" unpainted and painted red; maximum score 3,000. Also "Epoch Astro Command": 1982, VFD, four C cells, model 8230; also licensed to Tandy and Radio Shack under the same name.
- ↑ 3.0 3.1 3.2 3.3 3.4 Distinctly Average Grump, "Grandstand SCRAMBLE video game - Restoration & Repair + Airbrushing!", YouTube, 14 August 2024 (description read 2026-10-18; captions are disabled). A Scramble sold as not working: the case is two parts, a gloss black section and a painted silver section; the silver section was stripped, sanded and resprayed, the black section sanded with Micro-Mesh pads (1500-12000 grit) and polished with Novus polishes; the screen sticker's clear vinyl top layer was peeling, so it was removed and the sticker lacquered, a risk he notes; the worn white lettering on the control panel was redrawn with a paint marker. The fault and its fix are not named.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 4.14 4.15 4.16 Rust Belt Vintage Toy Repair, "1987 Radio Shack Astro Command Electronic Game Repair", YouTube, 31 October 2024 (transcript read 2026-10-18). Radio Shack's version, in its 1987 catalogue: four difficulty levels; the missile fires horizontally and the bomb drops vertically; a four-way joystick (0:23-1:57). Dead on four C cells (2:27-2:32). Disassembly: remove the batteries; peel the sticker off the joystick knob and remove the screw beneath; six screws separate the base from the top cover; the bezel unclips; two screws hold the main board's bracket (2:45-3:07). The D882 power transistor drives a switching supply whose transformer output is rectified to the voltages the processor and display need; it had failed, testing as "two resistors in series", and a new D882 cured the game (3:24-4:13, 6:11). He also replaced the three electrolytic capacitors as a precaution, same capacitance and same or higher voltage, observing polarity; no values given (4:22-4:44). Do not strain the thin piezo speaker wires; the battery contacts are wired and were removed for polishing; three screws free the control board and three more the joystick mount; contacts cleaned with denatured alcohol (4:54-5:22). The bezel clips back and the knob screw is hidden by the sticker (5:40-5:50).
- ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 5.11 retro_restos, "From Delivery to Repair in 10 Minutes. Grandstand Scramble 'No Power' Fix", YouTube, 8 February 2024 (transcript read 2026-10-18). Worked on and off from a 6 V negative-tip adaptor and not at all on batteries (1:38-2:57). In the DC socket the negative lead runs straight through and the positive lead from the batteries passes through the socket's contact to the board; a plug separates the two pins; old sockets "fall apart" and can switch the game off (3:43-4:24). With no plug in there was no continuity from the battery box to the board; the old socket was corroded and was replaced with a new-old-stock one with three pins, one negative and two positive (7:12-8:57). The cap over the joystick screw is glued; soak it off with acetone or alcohol and glue it back (4:45, 11:33-11:39). Six screws in the base, then lift the top away (5:25-6:06).
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Kip Hakes, "Grandstand Scramble - Boxed, Beautiful, Broken - Fix it Friday", YouTube, 1 March 2024 (transcript read 2026-10-18). A boxed Grandstand Scramble, dead on batteries, with worn button lettering (2:06-3:25). A screw under the top of the joystick; six screws in the base (3:01-3:35). The battery leads run to the DC socket, which cuts the batteries when a plug is in and can fail; about 6 V reached the power switch (5:58-7:31). He judged the display good because its getter was black, and said a white, powdery getter is bad (8:08-8:29). The capacitors were not bulging (8:51). Small surface-mounted parts on the back of the board, which he had not seen on similar boards (9:44-10:01). The NEC D882 tested dead on a component tester; a new one cured the game (10:32-14:38). Flicker on camera only (13:25).
- ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 Mike's Retro Tech, "55 - Grandstand Scramble - Electronic Game - Testing after 2 years on a shelf", YouTube, 15 December 2019 (transcript read 2026-10-18). A boxed Grandstand Scramble with its leaflet: the box reads Adam Leisure Group Limited, Harrogate, England, copyright 1982, and had faded on a shelf near the sun (0:43-1:09); the game ends when the ships are lost or at 3,000 points (2:37-2:49); the screen had been scratched by an adaptor packed in the box (4:51-5:04); controls joystick, on/off, SELECT, START, MISSILE and BOMB (6:48); the base label calls for four HP11 C cells or the Grandstand Universal Mains Adaptor with negative polarity (6:59-7:11); the leaflet names HP11 zinc-carbon or MN1400 alkaline cells and the Universal Mains Adaptor but gives no voltage (8:39-9:07). It worked on a universal adaptor set to negative.
- ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 retro_restos, "Grandstand Scramble Repair. No Power Fix", YouTube, 19 May 2023 (transcript read 2026-10-18). Dead on mains and batteries. Without a cover the cells "make a bid for freedom" (0:33-0:39). Adaptor: 6 V DC, negative (1:14). The DC socket's battery contact checked by continuity, open with a plug in as it should be (3:08-3:45); 5.8 V reached the board (3:58-4:18). The supply input read short to everything; the D882 power transistor had failed and a new one cured it; "the power transistors do tend to go after a while" (6:20-12:00). He covered the display while working (7:00). Battery contacts polished; it then worked on batteries (11:18-11:35). Flicker on camera only (11:50).
- ↑ 9.0 9.1 Wojciech Pędzich, File:Konsola Grandstand Scramble w zasobach muzeum Gry i Komputery Minionej Ery we Wrocławiu.jpg (CC BY 4.0), photograph of a working Grandstand Scramble at the Gry i Komputery Minionej Ery museum, Wrocław: the two round fire buttons are labelled BOMB and MISSILE, beside the SELECT and START buttons and the joystick; a mains adaptor lead is plugged into the right-hand side.
- ↑ 10.0 10.1 10.2 10.3 10.4 10.5 10.6 10.7 10.8 Handheld Museum forum, "EPOCH Astro Command - dead or dying", January 2016 (retrieved 2026-10-18). Rik (site administrator): an Epoch VFD game will play and make its sounds even without the display or the small transformer that powers it; he has never had a VFD die unless its glass was broken; with heavy use the displays fade, unevenly, over years; a broken filament wire leaves an area of the display very dim; a dead game is normally a transistor or two blown by an incorrect power supply. The owner of the Astro Command (the Epoch version of Grandstand Scramble) found its supply runs from the control board to the main board through a flat cable, which frayed and broke after the board had been turned over repeatedly.
- ↑ 11.0 11.1 11.2 11.3 11.4 11.5 Retro Tech Repair, "Grandstand Scramble / Astro Command Repair - Retro Games", YouTube, 7 December 2018 (transcript read 2026-10-18). A dead Grandstand Scramble with surface corrosion in the battery box (1:18-3:40). The joystick knob is held by a small screw under a sticker on its top, and the sticker cannot easily be replaced (2:12-2:42). Tip for the plastic screw posts: turn each screw backwards until it drops into its thread before tightening, so as not to strip the post (5:46-5:53). An electrolytic capacitor had burst, a 330 μF 10 V part mounted lying down, and was replaced with a 330 μF 25 V part (6:30-11:17); the D882 power transistor, also mounted lying down, read short base to collector and open to the emitter, and was replaced (9:33-13:28). With both replaced the game worked from a 6 V bench supply, so the video does not show which part was the cause (13:56-14:43). Battery contacts were taken from a second, damaged Scramble (15:08). VFD flicker on camera is not visible in person (16:56). Fire buttons: missile and bomb (17:20).
- ↑ 12.00 12.01 12.02 12.03 12.04 12.05 12.06 12.07 12.08 12.09 12.10 12.11 Vintage Gaming Memories, "Joystick Repair & Full Cleaning: 1982 Epoch Astro Command", YouTube, 4 March 2025 (transcript read 2026-10-18). An Epoch Astro Command whose joystick did not return to centre (4:50-5:08). Six screws in the base; the joystick cap comes off after peeling a small sticker and removing the screw beneath (5:13-5:52); three screws release a part joined to the board by a flat cable, to be handled carefully (6:58-7:26); four screws hold the joystick cover over its contacts (7:44-7:58). The joystick was cleaned and given dry lubricant; contact cleaner was sprayed on its spring and on the springs under the MISSILE and BOMB buttons; the slide switch was polished where it rubbed (8:18-10:52). The inside of the display window and the plastic film with the base and space imagery were cleaned (11:28-11:37). Five phases and four skill levels (12:24).
- ↑ YoxxxoY Jorge, "Battery cover Epoch electronic games", Thingiverse 3399673 (2 February 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. Licensed CC BY.
- ↑ retro_restos, "Astro Wars 'No Display' Repair ... VFD Game Transformer Replaced", YouTube, 14 November 2023 (transcript read 2026-10-18). Repairer who reports fixing 5-10 Astro Wars a week. Phone chargers and the wrong adaptors blow the power transistor; a Scramble that came with a 9 V positive-pin adaptor reading nearly 13 V; "all of these games were a negative polarity and only run at 6 volts" (1:00-3:00). His repair kit contains a power transistor, all the electrolytic capacitors, a DC input socket and a diode, and its notes say to replace S02, the input socket and S06, in that order, as the commonest faults; a broken display tube, rotten battery terminals or a broken joystick need donor parts (3:00-6:00). Seven screws, some holding the silver hood and three holding the control panel, the smallest in the middle; hold the base of the controls and lift up and forward (8:00-10:00). Inside: Fresnel screen and backdrop; fire button and its spring, power and start switches whose contact leaves can be bent for more spring; felt cover over the joystick; carbon contacts on the SELECT, START and FIRE pads (10:00-12:00). Four screws hold the cover with the colour lens; on overheated games this lens burns, distorts and its tape comes off (12:00). This game had sound and no display because its transformer coil had fallen apart, a failure he had not seen in 50-100 repairs; a transformer from a donor board, fitted by its orientation arrow, cured it (12:00-24:00). He greases the power switch slider (26:00).
- ↑ Centre for Computing History, "Grandstand Scramble", CH49305 (retrieved 2026-10-18): 1982; the player flies from left to right, dropping bombs on missiles and ground targets and firing at missiles and aircraft; the VFD can show different images in one square, "a bullet one moment and a spaceship the next"; an industrial landscape laminate under the screen; joystick, on/off switch, select, start and two fire buttons, which the record calls missile and bullet.