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Grandstand Caveman Capacitor Replacement Guide

From RetroTechCollection
Caveman handheld game
A Grandstand-branded Caveman. The main board inside is Tomy's TN-12 2E114E03 (Christo; CC BY-SA 4.0).

The electrolytic capacitors on the main board of the Grandstand Caveman (Tomy and Tandy Caveman). No parts list or schematic has been published. The values here come from the Korean repairer analo9's 2026 repair of a Tomy Caveman that would not switch on: the five electrolytics were removed from the TN-12 2E114E03 board and photographed together, and the board's silkscreen prints the value beside three of the positions. Both photographs were looked at at full size.[1] Tomy, Tandy and Grandstand sold the same game on the same board.[2]

analo9 replaced all five as part of a repair whose first fault was a battery contact; the write-up does not say that a capacitor had failed.[1] Replace them when one is visibly leaking or bulging, when the display supply misbehaves, or as part of a restoration. See Capacitor Failure Symptoms.

The capacitors

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All five are radial electrolytics on the main board. Positions are given with the board component side up, the display tube along the top edge and the green transformer at the top right, as in analo9's photographs.[1]

Caveman (TN-12 2E114E03) electrolytic capacitors
Position Value Voltage Evidence Notes
Centre, beside the C945 transistor and link J11 3.3 µF 50 V Board silkscreen "3.3U 50V"; a removed capacitor marked 3.3 µF 50 V Grey NTK part
Lower right, beside the RD12EB3 zener 10 µF 50 V Board silkscreen "10UF 50V"; a removed capacitor marked 10 µF 50 V
Lower right, below the 10 µF 47 µF 50 V Board silkscreen "47UF 50V"; a removed capacitor marked 47 µF 50 V
One of the two remaining positions (lower right edge, or beside the transformer) 33 µF 25 V A removed capacitor marked 33 µF 25 V Position not identified from the photographs
The other remaining position Not legible Not legible The fifth removed capacitor, its marking turned away from the camera Read the part fitted

The board also carries small ceramic capacitors marked on the silkscreen SL121J and SL471J (both 50 V) and Z223Z (50 V).[1] On another no-power Tomy Caveman, analo9 replaced a small ceramic capacitor beside the C945 together with the C945 itself.[3]

Procedure

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  1. Take the cells out, lift off the top shell and the smoked display housing, and lift the main board out with the display, as described on Grandstand Caveman General Maintenance.
  2. Photograph the board and note the polarity of each capacitor before removing anything.
  3. Read each part as it comes out. The two positions this table cannot assign must be checked against the parts in your hand.
  4. Fit 105 °C radial electrolytics of the same value and at least the same voltage. Keep them no taller than the originals so that the display housing and top shell still fit.
  5. Clean flux off with isopropyl alcohol and refit.

After the work

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  • Switch on with the selector set: the display should show the dinosaur, its children, the dragon, the eggs and the volcanic bombs, and START/SHOOT should play the fanfare.[4]
  • If the display is still dark, see Sound but no display on the troubleshooting guide.
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References

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  1. ↑ 1.0 1.1 1.2 1.3 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.
  2. ↑ 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".
  3. ↑ 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.
  4. ↑ 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.


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