Grandstand Star Force Troubleshooting Guide
Fault-finding for the Grandstand Star Force, Epoch's Star Force sold in the UK by Grandstand.[1] No service data, schematic, board photograph or written repair has been published for it. What can be said comes from Grandstand's booklet, the Handheld Museum's reading of the microcontroller, and the descriptions of two repair videos whose narration could not be retrieved; where the closely related Epoch games help, they are named as such. Opening the case and routine care are on Grandstand Star Force General Maintenance.
What should happen at power-on
[edit | edit source]With four good C cells, or an adaptor set to negative polarity, and POWER on:[2]
- An electronic melody plays and the display lights.
- "L1" shows at the top of the display: the game starts at skill level 1 and phase 1.
- The skill level select button steps through four levels, and the phase select button chooses any of the seven phases as the starting point.
- START sounds and shows the number of lives (9, 7, 7 or 5 by level).
- With SOUND switched off the game runs silently.
Expected measurements
[edit | edit source]No voltages or currents have been published for a Star Force. Four fresh C cells give about 6 V.[2] Its microcontroller, an NEC D7528C-016, belongs to the same family as the Firefox F-7's D7528C 011; that game's power section, as drawn by an owner, is a D882 transistor driving a small transformer, but whether Star Force's is the same has not been published.[1][3]
Symptoms
[edit | edit source]| Symptom | Likely cause | Action | Source |
|---|---|---|---|
| No sound, game otherwise normal | SOUND switched off | Switch it on. | [2] |
| Game malfunctions or the display is erratic | Weak cells | Fit fresh cells. | [2] |
| Power comes and goes on the adaptor | Faulty DC socket | Clean or replace the socket on the right-hand side. | [4][2] |
| Dead | Cells, battery contacts, DC socket or power switch; beyond that, the power section | Check 6 V reaches the board with the switch on. On the Epoch games with published repairs the power transistor is the usual next suspect, but Star Force's power section has not been documented. | [5][6] |
| Controls or joystick unresponsive | Not stated in the one report | Clean the control contacts and check the pads. | [4] |
| Screen mount broken | Broken mounting post or bracket | Repair the mount before refitting the screen. | [4] |
| Game plays and sounds but the display is dark | Display supply or tube | The game runs without its display; look at the display's supply first. | [6] |
Reports of faults
[edit | edit source]- retro_restos's Star Force (2023) was grubby, with an intermittent power socket, a broken screen mount and unresponsive controls, and a bad joystick; the video works through all of them, and its description calls it a rare look inside the game.[4]
- Repairing Faulty Tech's Star Force (2025) would not power on; the description does not give the cause.[5]
- No capacitor values, part numbers or measurements from either repair have been published in text, so no capacitor list can be given.
Display faults
[edit | edit source]The Handheld Museum's administrator, writing about Epoch VFD games in general, says the game plays and makes its sounds without the display or the transformer that powers it, that he has never had a display fail unless its glass was broken, and that displays fade unevenly over years of heavy use, with a broken filament wire leaving an area dim.[6] The Star Force's tube has not been identified, so a broken one can only be replaced from another Star Force or Epoch Star Force, or the Yeno Super Galaxy II, which a collector identifies as the same game.[7]
Things that are not faults
[edit | edit source]- Silence with SOUND off.[2]
- Play starting from a later phase: the phase select button sets it.[2]
- Fewer lives at higher skill levels (9, 7, 7 and 5).[2]
What is realistically repairable
[edit | edit source]| Part | Status | Source |
|---|---|---|
| Battery contacts | The same part as Astro Wars; reform or swap | [8] |
| Battery cover | 3D-printable Epoch cover | [9] |
| DC socket | Replaceable | [4] |
| Microcontroller (D7528C-016) | Donor only | [1] |
| Display tube | Donor only | [7] |
Related pages
[edit | edit source]- Grandstand Star Force
- Grandstand Star Force General Maintenance
- Grandstand Firefox F-7 Troubleshooting Guide: the game whose microcontroller is from the same NEC family.
- Grandstand Astro Wars Troubleshooting Guide
- Grandstand Universal Mains Adaptor
References
[edit | edit source]- ↑ 1.0 1.1 1.2 Handheld Museum, "Grandstand Star Force" (retrieved 2026-10-18): 1984, VFD, four C cells, model 11055, "CPU: NEC D7528C-016"; Grandstand release of Epoch's Star Force. Also "Epoch Star Force": 1984, VFD, four C cells.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Grandstand, Star Force instruction booklet (distributed by Adam Imports Ltd, Ripon Way, Harrogate, a member of the Adam Leisure Group PLC; printed in Japan; no date printed), hosted here as File:Grandstand Star Force Instructions.pdf (PDF page numbers). p. 1: drawing of the controls (power switch, sound switch, firing button, joystick, skill level select, start and phase select buttons) with the adaptor plug entering a socket on the right-hand side, and the batteries box: four Duracell MN1400 cells; the Grandstand Universal Mains Adaptor, not included, with its polarity switch set to negative; the game will not work properly on weak batteries; if it malfunctions or the display is erratic, check or replace the batteries; switch off after play and remove the batteries when the game is not used for long periods; care note: "move the Joy Stick gently. Do not press hard on the Firing Button ... Do not leave in sun or allow it to get wet." At switch-on an electronic melody plays and the display lights; the game is set to skill level 1 ("L1" at the top of the display) and phase 1; with the sound switch OFF the game plays without sound effects; START sounds and shows the number of lives. p. 2: the joystick moves the Space Fighter left and right. p. 6: the game ends with no lives left or at the perfect score of 3,000.
- ↑ 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; electrolytic capacitors C01 to C04 and other capacitors C05 to C15, without values; 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.
- ↑ 4.0 4.1 4.2 4.3 4.4 retro_restos, "Vintage Electronic Grandstand Star Force Teardown & Repair. Broken Screen, Power Fix & Bad Joystick", YouTube, 21 June 2023 (description read 2026-10-18; the transcript could not be retrieved): "a rare opportunity to see inside the Star Force game"; the game was grubby, with an intermittent power socket, a broken screen mount and unresponsive controls, which the video works through.
- ↑ 5.0 5.1 Repairing Faulty Tech, "Grandstand STAR FORCE 80's game won't power on - Can I fix it?", YouTube, 13 April 2025 (description read 2026-10-18; the transcript could not be retrieved): a Star Force that would not power on; the description does not give the fault or the outcome.
- ↑ 6.0 6.1 6.2 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.
- ↑ 7.0 7.1 Handheld Museum forum, "Epoch Star Force", 2012-2019 (retrieved 2026-10-18), high-score thread: the game is fast; a member notes that the uncommon Yeno Super Galaxy II is "the same as Epoch and Grandstand's Star Force".
- ↑ retro_restos, "Grandstand Astro Wars Service & Repair from Ebay Vintage Games Bundle", YouTube, 2 October 2024 (transcript read 2026-10-18). Strip-down service: carbon contacts cleaned; power slider contacts bent for spring and greased; fire button spring stretched slightly (2:00-4:00). A stretched battery spring was unsoldered, reformed with pliers and refitted; the Star Force has "exactly the same battery contact" (4:00-8:00). The Fresnel screen, star backdrop and front screen come out; the front screen was polished and its back cleaned with glass cleaner (10:00-12:00). "Astro Wars is notorious for throwing the batteries out when you're trying to put them in" (16:00).
- ↑ 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.