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Grandstand Caveman General Maintenance

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Caveman handheld game
A Grandstand-branded Caveman with its display lit. The case, controls and "TOMY" moulding on the base are Tomy's (Christo; CC BY-SA 4.0).

Care, cleaning and dismantling of the Grandstand Caveman (sold in the UK as Cave Man - Jr. Caveman vs Dinosaur), a tabletop game with a vacuum fluorescent display (VFD) made in Japan by Tomy. Tomy sold it as Caveman (model 7613) and Radio Shack as the Tandy Caveman; the three releases share Tomy's board, display and case.[1][2][3] No service manual has been published. What follows comes from Tomy's UK instruction book, the MAME driver notes, and four repairs: three by the Korean repairer analo9 on Tomy units and one on a Grandstand-branded unit by the Buy it Fix it channel. Fault-finding is on Grandstand Caveman Troubleshooting Guide and the capacitors on Grandstand Caveman Capacitor Replacement Guide.

What is inside

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Caveman construction
Part What it is Source
Case A base and a one-piece top shell that forms the display hood and the front. The printed window plate and the black control faceplate clip into the top shell analo9 photographs, video[4][5]
Battery box Four C ("baby") cells in two rows, under a cover at the rear of the base Tomy leaflet, photographs[6][4]
Main board Marked TN-12 2E114E03; lies flat in the base; NEC D553C 209 microcontroller; the display supply (green transformer, TO-126 transistor marked D471, C945 transistor, diodes and five electrolytics), mostly at the right-hand end MAME, photographs[1][4][7]
Display NEC FIP8AM20T VFD, eight grids, standing upright in black rubber end blocks inside a smoked plastic housing MAME, photographs[1][4]
Control board Green, marked 2E114E02; contact pads for the MOVE lever and the START/SHOOT button, tracks for the AMA/PRO and ON/OFF slide switches, and a W06A diode between pads marked BAT and AC Photographs[4][7]
Switch carrier Black plastic frame with yellow sliders, screwed down over the control board Photographs, video[4][5]
Power socket In the right-hand side of the base, below the display hood Leaflet drawing, photographs[6][4]
Sound Piezo disc on a lead Photographs[7]

Before you start

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  • Take the cells out.
  • Photograph each stage: the faceplate, the switch carrier and the yellow sliders come apart in several pieces.[4][5]
  • Keep the rubber contacts, springs and sliders from any scrap game of the same family; no new spares are known.[8]

Opening the case

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  1. Switch off and open the battery cover at the rear of the base; take the cells out.[6]
  2. Turn the game over and remove the screws in the base.[5]
  3. Lift the top shell straight up. It carries the window plate and the control faceplate; the yellow slider knobs and the START/SHOOT cap stay with the switch carrier in the base.[4][5]
  4. The display now stands upright on the main board inside its smoked housing. Lift the housing off over the tube.[4]
  5. Unscrew the black switch carrier to reach the green control board and its rubber contacts.[5][4]
  6. The boards lift out together with the display. Leads run to the battery terminals, the DC socket and the piezo disc; free them from their guides; do not pull on them.[4]

The display is a glass vacuum tube with a sealed glass tip at one end. Hold it by its rubber end blocks. A tube that cracks lets air in and cannot be repaired; a replacement can only come from another Caveman.[1][9]

Batteries and contacts

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Tomy Caveman Instructions battery compartment drawing
The battery compartment at the rear of the case, from Tomy's UK instruction book: four C cells in two rows.
  • Fit four C cells as the moulding shows. Tomy's book calls them "1.5 V baby cells".[6]
  • Corroded battery contacts are the fault found most often on this game. The Tomy Caveman analo9 repaired in 2026 would not switch on because of a battery contact fault, and the contacts had to be restored.[4] The Grandstand Caveman repaired by Buy it Fix it had spent 20 years in an attic; its battery terminals were measured, then cleaned with swabs and contact cleaner before it would run.[5]
  • Clean the contacts back to bright metal and follow the red battery leads to the board, looking for green or broken wire. See Battery Explosion, Capacitor or Corrosion Damage.
  • Tomy's care notes: do not leave used cells in the game, and switch it off when not in use.[6]

The DC socket and adaptors

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  • Tomy's UK book asks for an adaptor of 7.5 V DC, 200 mA, with a 2.1 mm coaxial plug, tip (centre) negative. It says to disconnect the adaptor when the game is not in use and to use no other adaptor.[6] Measure the plug before connecting it: centre negative is the reverse of most modern adaptors.
  • The adaptor plugs into the socket in the right-hand side of the base.[6][4]
  • On the control board the adaptor and battery supplies meet at a W06A diode between the pads marked BAT and AC. On one Tomy Caveman that would not switch on, this diode was replaced.[7]
  • No Grandstand leaflet for Caveman has been found to say which setting to use on the Grandstand Universal Mains Adaptor.
  • A wrong adaptor is the commonest cause of damage to VFD tabletop games in general, usually a blown transistor.[8]

Lever, button and switches

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  • The MOVE lever, the START/SHOOT button and the two slide switches act on contact pads and tracks on the green control board. Buy it Fix it cleaned the pads, the rubber contacts and the slide-switch carrier with isopropyl alcohol on swabs.[5] analo9 cleaned the key contacts on the 2026 repair and overhauled a red export Caveman whose controls misbehaved.[4][10]
  • Wipe the pads; do not scrape their plating.
  • Set the AMA/PRO selector before switching on. It cannot be changed during a game; switch off and reset it.[6]

Window, faceplate and case

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  • The window plate and the black control faceplate unclip from the inside of the top shell.[4] Clean the printed plate with a damp cloth only: the "CAVEMAN" artwork and score legend are printed on it.[3]
  • Cases were made in gold, red, and white and orange.[2][10]

Display

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  • MAME's notes on NEC display tubes record that the phosphor colours fade after decades.[1]
  • analo9 cleaned the tube during both no-power repairs.[4][7]

Storage

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Tomy's care list: no extremes of temperature, keep the game dry and clean, do not shake or drop it, switch it off when not in use, and do not leave used batteries in it.[6]

Maintenance checklist

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  1. Cells out; inspect the battery box, contacts and leads.
  2. Clean the contacts; test on fresh cells.
  3. Test on a measured 6-7.5 V, centre-negative supply through the side socket.
  4. Clean the control board pads, rubber contacts and slide-switch tracks if any control is unreliable.
  5. Check the W06A diode on the control board if the game is dead on one supply only.
  6. Store with the cells out.
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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 MAME source, hh_ucom4.cpp (retrieved 2026-10-18). Driver notes for Tomy Caveman: made in Japan; PCB label TN-12 2E114E03; NEC uCOM-43 microcontroller labelled D553C 209, 1-bit sound; cyan/red/green VFD NEC FIP8AM20T no. 2-42; releases Caveman (Tomy, world), Caveman (Tandy, USA) and "Cave Man - Jr. Caveman vs Dinosaur, published by Grandstand" (UK); inputs left, right, one button and the AMA/PRO switch; the machine configuration clocks the D553 at 400 kHz. The chip list dates the D553C 209 to 1982. File header: NEC FIP part numbers give the number of grids; "after decades passed, all the colors fade".
  2. ↑ 2.0 2.1 Handheld Museum, "Grandstand Caveman" and "Tomy Caveman" (retrieved 2026-10-18): 1982, VFD, four C batteries; Tomy model 7613; made by Tomy and licensed to Grandstand for UK distribution; found in gold and in white and orange cases; also sold by Radio Shack under the Tandy name.
  3. ↑ 3.0 3.1 Christo, File:Caveman handheld game.jpg (Wikimedia Commons, CC BY-SA 4.0): a Grandstand-branded Caveman, bezel reading "Jr. CAVEMAN VS DINOSAUR", "CAVEMAN", "TOMY MICRO COMPUTER GAME" and "GRANDSTAND"; MOVE lever, AMA/PRO and ON/OFF switches, START/SHOOT button; "TOMY" moulded into the base.
  4. ↑ 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 analo9 (아날로그 탐구생활), "1981년 추억의 게임기 『토미 케이브맨』(TOMY CAVEMAN)", Naver blog, 3 September 2026 (in Korean; retrieved 2026-10-18), with the matching YouTube video OOn3iG6zNIk. A gold Tomy Caveman that would not switch on: diagnosed as a battery contact fault; the game was dismantled, the board removed and checked and parts replaced; the display and the key contacts were cleaned; the battery contacts restored. 47 photographs (1280 px), looked at at full size: the DC socket in the right-hand side of the base; the battery cover under the rear of the base; four C cells in two rows; the top shell (hood and front in one piece) lifted off with the printed window plate and the black control faceplate clipped inside it; the display standing upright in black rubber end blocks inside a smoked plastic housing; the main board TN-12 2E114E03 lying flat in the base with the green control board 2E114E02 beside it under a black switch carrier with yellow sliders; the five electrolytics removed from the main board, marked 3.3 µF 50 V, 10 µF 50 V, 33 µF 25 V and 47 µF 50 V (the fifth's marking faces away); the main board silkscreen "3.3U 50V" beside the C945, "10UF 50V" and "47UF 50V" beside the RD12EB3 zener, a blue resonator marked CSB, SL121J and SL471J 50 V and Z223Z 50 V capacitors, 1SS53 and W06C diodes, D471 and C945 transistors, resistor networks RGSD12X154M and RGSD14X154M.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Buy it Fix it, "Repairing A Vintage Tomy / Grandstand Caveman Game", YouTube, 8 September 2022, 17:03 (watched 2026-10-18; no transcript available). A Grandstand-branded Caveman sold on eBay as "Been in attic for last 20 years. Unable to get working"; dead on fresh C cells. Shown: the screws in the base removed and the top shell lifted off (1:30-2:00); the control faceplate and switch carrier removed (2:15); the control board's contact pads and the rubber contacts cleaned with isopropyl alcohol on swabs (3:00-5:00); the slide-switch carrier cleaned (7:30-8:45); the battery terminals measured (9:15) and cleaned with swabs and contact cleaner spray (10:00-12:30); the display then lit on the cells (13:15) and the reassembled game played (16:15-16:30).
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 Tomy, Caveman instruction book, UK edition (marked GB), hosted here as File:Tomy Caveman Instructions.pdf. Page 1: controls drawing (MOVE lever, SHOOT button that also starts the game, power switch, game selector AMA/PRO); "Open the cover of the battery compartment at the rear of the game-machine. Insert four 1.5 V baby cells as shown in the diagram"; "The computer may fail to function properly depending on how the game-machine is switched on. If it does not work, turn the Power Switch off"; AC adaptor 7.5 V DC 200 mA, 2.1 mm ID coaxial plug, tip (centre) negative; "When not in use, disconnect the adaptor. Do not use any other adaptor than the type recommended". Page 3: set the selector before switching on; it cannot be changed once the game has started. Page 4: scoring; the score display reads to 1,990 points and then returns to 0, with an egg in the cave lit for each 2,000; care: no extremes of temperature, avoid wet or dirt, "Don't take it apart", don't shake or drop, switch off when not in use, don't leave used batteries in; "If the batteries become weak the display screen will become dark and show incorrect action"; drawing of the adaptor plug entering the socket in the side of the case.
  7. ↑ 7.0 7.1 7.2 7.3 7.4 analo9, "1981 추억의 게임기 『토미(영실업) 케이브맨』(TOMY CAVEMAN)", Naver blog, 21 November 2023 (in Korean; retrieved 2026-10-18), with the video -QnFHPQRNxI. A gold Tomy Caveman (imported to Korea by Young Toys in 1984) that would not switch on, repaired and overhauled: circuit checked, parts replaced, power tested, display cleaned. Photographs: the W06A diode on the control board 2E114E02, between the pads marked BAT and AC, replaced (the old glass diode shown beside the board); a C945 transistor and a small ceramic capacitor removed from beside the TO-126 power transistor marked D471; the back of the tube marked NEC FIP8AM20T.
  8. ↑ 8.0 8.1 Handheld Museum forum, "Astro wars / galaxy ii repair", December 2018 - February 2019 (retrieved 2026-10-18). The site administrator (Rik), writing about VFD tabletop games in general: the wrong AC adapter "will usually fry" a transistor, "the most frequent damage I've seen to VFD games"; keep rubber buttons, springs and speakers from scrapped games as spares.
  9. ↑ Handheld Museum forum, "EPOCH Astro Command - dead or dying", January-February 2016 (retrieved 2026-10-18). The site administrator (Rik), writing about VFD tabletop games in general: displays fade unevenly with heavy use; he has never had a display fail unless the glass was broken.
  10. ↑ 10.0 10.1 analo9, "1981 토미 LSI 게임기 "케이브맨"(TOMY CAVEMAN)", Naver blog, 2 November 2022 (in Korean; retrieved 2026-10-18). A red Caveman made for export to North America: it powered up but its control buttons misbehaved, and it was dismantled and overhauled.


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