Grandstand Munchman Troubleshooting Guide
Fault-finding on the Grandstand Munchman, Grandstand's UK release of Tomy's round VFD tabletop Pac-Man (Tomy Pac Man, Puckman and Puck Man are the same game).[1][2] No service manual or schematic has been published. The faults below come from owners' repairs of Munchman and Tomy Puck Man units, the MAME driver notes and Tomy's instruction sheet; each row names its source. Dismantling, cleaning and the adaptor rating are on Grandstand Munchman General Maintenance.
What a working game does
[edit | edit source]- Switch on and the game starts by itself: a fanfare plays and the first screen shows the segment number (P-01), the Pac-Men left and the number of monsters in the segment.[3][2]
- The maze follows, with Pac-Man at the bottom right; play begins when the monsters start flashing.[3]
- The sound is loud. One owner called it "very loud".[4]
Measurements
[edit | edit source]| Point | Value | Source |
|---|---|---|
| Battery supply | 6 V from four C cells in series; about 6.0 V measured on a repaired Munchman | Blogs, video[4][5][6] |
| Adaptor (Tomy) | 7.5 V DC, 200 mA, 2.1 mm plug, centre negative | Tomy leaflet[3] |
| Microcontroller supply | Up to about 10 V (negative; the μPD553 is a PMOS part on a single −10 V rail) | Ingmar's Retroblog, NEC data sheet[5][7] |
| Display drive | About 30-38 V on the segment outputs; NEC rates the outputs to −35 V | Ingmar's Retroblog, NEC data sheet[5][7] |
| Clock | 430 kHz | MAME driver, Handheld Museum forum[2][8] |
No voltages at named test points have been found. The microcontroller and display voltages come from the converter on the main board, so measure them with the cells fitted and the game switched on, and keep fingers off the transformer and its diodes.
Symptom table
[edit | edit source]| Symptom | Likely cause | Action | Source |
|---|---|---|---|
| Works on the adaptor, dead on cells | The DC socket's switch contact no longer connects the battery box; the socket pin pushed out of place by the plug | Replace the socket with a 2.1 mm type that has a battery-break contact; re-test on cells alone | [9][10] |
| Dead on cells and on the adaptor | Corroded battery contacts or leads; dirty power switch contacts; a fault on the main board | Clean the battery box and contacts; clean the slide-switch tracks; measure the supply at the board; then see below | [5][11] |
| Display dark or dim, play goes wrong | Weak cells | Fit fresh alkaline C cells | [3] |
| A direction key does nothing or works only when pressed hard | Worn conductive coating on the rubber mat; dirty pads | Clean the pads and mat; re-coat the mat's contacts with soft graphite | [5] |
| AMA/PRO or power switch unreliable | Tarnished slider wipers or board tracks | Clean the tracks and wipers | [5][11] |
| Died after a different adaptor was used | Reversed polarity or excess voltage; a blown transistor in the supply | Check the TO-126 power transistor and the C2785 out of circuit | [12][6] |
| Sound plays but the display stays dark | The display converter (transformer, power transistor, diodes) or a broken tube | See below | [5] |
| Faded or patchy colours | Phosphor wear with age | Not repairable | [2] |
| Window scratched or cracked | Wear | Polish scratches; a cracked window cannot be repaired | [9][10] |
Dead and silent
[edit | edit source]- Fit fresh cells and measure 6 V at the battery terminals.[4]
- Plug in a measured supply. If the game now works, the fault is in the cells, the battery contacts or the DC socket's switch contact (see the table).[9]
- If it is dead on both, open the case and follow the supply from the socket and battery box through the OFF/ON slide switch on the control board to the main board. analo9's Puck Man would not switch on even from an adaptor; the repair began with cleaning the switch contacts before the board itself was repaired. The write-up does not say which part was faulty.[11]
- Check the W06A diode between the AC GND and GND pads on the control board, which sits in the adaptor's return path.[5]
- Retro Tech Repair's Munchman measured about 6 V on the supply but did not run; the TO-126 power transistor and a TO-92 transistor were taken out and tested against their data sheets (the data sheet on the bench was for a 2SD882).[6] Test these two transistors out of circuit; the board silkscreen marks the small one C2785.[11]
Sound but no display
[edit | edit source]If the fanfare and the game sounds play but the display stays dark, the microcontroller is running, so the fault lies in the part of the supply that feeds only the display, or in the tube itself. Ingmar's Retroblog describes the display supply as a small discrete DC-DC converter: a transformer driven by a transistor.[5] Its parts on the TN-08 board are the blue transformer, the TO-126 power transistor, the C2785, the 1SS53 and W06C diodes and the RD12EB3 zener, with the electrolytics listed on Grandstand Munchman Capacitor Replacement Guide.[11] No Munchman-specific report of this fault has been found.
The Handheld Museum's administrator has never had a VFD fail in these games unless its glass was broken.[13] Check the glass envelope and the sealed tip at one end of the tube for cracks before replacing parts; a tube that has let air in cannot be repaired.
Game misbehaves or will not start
[edit | edit source]- Weak cells cause wrong play before anything else; replace them first.[3]
- The D553C 160 runs from a ceramic resonator. MAME clocks the game at 430 kHz and an owner who checked his Munchman found a 430 kHz part, different from the 400 kHz resonator in the Epoch Invader From Space.[2][8] The resonator's position on the TN-08 board is silkscreened CSB400P.[11] The two sources disagree, so read the marking on the part fitted and replace like for like.
- The program is mask-programmed into the D553C 160. A failed microcontroller can only be replaced from another copy of the same game: Tomy's Pac Man, Puckman or Puck Man, Futuretronics' Pac Man-1, or another Munchman.[2][8]
Things that are not faults
[edit | edit source]- The game starts on its own at switch-on; there is no start button.[2]
- Pac-Man only eats dots while moving from right to left; moving right past a dot leaves it in place.[3][9]
- After the last Pac-Man is lost the screen flickers until the game is switched off.[3]
- "GOOD" in the score display means five segments have been cleared.[3]
What is repairable
[edit | edit source]- Repairable: battery corrosion, the DC socket, switch and key contacts, the window, the transistors, diodes and capacitors of the display supply.[5][10][6]
- Replaceable only from a donor game: the D553C 160 microcontroller and the FIP8AM18T display tube.[2]
- Not repairable: a cracked tube, faded phosphor, a cracked window.[9]
Related pages
[edit | edit source]- Grandstand Munchman
- Grandstand Munchman General Maintenance
- Grandstand Munchman Capacitor Replacement Guide
- Grandstand Caveman Troubleshooting Guide
- Grandstand Tron Troubleshooting Guide
- Grandstand Universal Mains Adaptor
References
[edit | edit source]- ↑ Handheld Museum, "Tomy Pac Man, Etc." and "Guts" (retrieved 2026-10-18): model TKY-7612, four C cells; the Pac Man, Puckman, Puck Man and Munchman releases are "identical except for the sticker with the name on it, and the instructions on the bottom"; "Munchman was released in the U.K. by Grandstand (but says Tomy on the bottom.)". The Guts page photographs a Tomy Pac Man with its top removed: the VFD in black end blocks above the board, the control board with its contact pads, and leads to the battery box and the socket.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 MAME source, hh_ucom4.cpp (retrieved 2026-10-18). Driver notes for Tomy Pac-Man: made in Japan; PCB label TN-08 2E108E01; NEC uCOM-43 microcontroller labelled D553C 160, 1-bit sound; cyan/red/green VFD NEC FIP8AM18T no. 2-21; bright yellow round casing; releases Puck Man (Tomy, Japan), Pac Man (Tomy, USA), Puckman (Tomy, UK) "and also published by Grandstand as Munchman", Pac Man-1 (Futuretronics, Australia); "The game will start automatically after turning it on"; dots can only be eaten going right to left. The machine configuration clocks the D553 at 430 kHz. File header: NEC FIP part numbers give the number of grids after "FIP"; "after decades passed, all the colors fade".
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Tomy Corporation, Tomytronic Pac Man instruction sheet, copyright 1981, Carson, California, printed in Japan; the US edition of the leaflet for the game Grandstand sold as Munchman. Hosted here as File:Tomy Pac Man Instructions.pdf. Page 1: controls drawing (game selector switch AMA/PRO, ON-OFF power switch, four PAC MAN control buttons); "Insert batteries": turn the power switch off, turn the game over and push the battery cover in the direction of the arrow to slide it open; four C cells, long-life or alkaline recommended; recommended AC adapters Archer cat. no. 270-1551 A and Recoton AD-10UL; adapter requirements 7.5 V DC 200 mA, 2.1 mm ID coaxial plug, tip (centre) negative; "Taking care of your game": no excessive heat or cold (car glove compartment, heater vent), avoid wet or dirt, "Don't take it apart", don't shake or drop, turn off and remove the batteries for storage, no dead batteries left in; "If the batteries become weak the display screen will become dark and show incorrect action". Page 2: unplug the adapter when not in use and use no other adapter; switching on plays a fanfare and shows P-01 with the remaining Pac-Men and the number of monsters; the game begins when the monsters flash; Pac-Man cannot eat bait behind it; two monsters in segments 1-3 on AMA, three from segment 4, three throughout on PRO; when all Pac-Men are lost "the game screen will flicker until the power switch is turned off".
- ↑ 4.0 4.1 4.2 windytan (Oona Räisänen), "Tomy Electronic PUCKMAN", May 2013 (retrieved 2026-10-18). A Tomy Puckman bought at a flea market: D-pad controls, on/off and AMA/PRO switches; VFD with every sprite position pre-printed; main chip marked D553C-160 (photograph shows "NEC JAPAN 8228EK D553C 160" and the board silkscreen PCJTN-08); four C cells, 6 V, or an AC adapter; run from a 6 V DC adapter "hooked up to the battery terminals"; the sound is "very loud".
- ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 Ingmar's Retroblog, "„Puckman" (oder „PackMan")?", 26 May 2020 (in German; retrieved 2026-10-18). Restoration of a Tomy Puckman (model TKY-7612) with photographs: four C cells in series, 6 V, plus a socket for a plug-in adaptor; four white direction keys and two slide switches (power and difficulty); NEC μPD553C, whose outputs drive the VFD segments directly at about 30-38 V while the chip itself runs from up to 10 V DC, clocked between 150 and 440 kHz; a small discrete DC-DC converter (a transformer with a driver transistor) supplies the display; sound from a piezo sounder; the keys are on a separate board whose contact areas are closed by a rubber membrane with a conductive coating. The game was taken fully apart and every part cleaned; the membrane's contact points were re-coated with a soft graphite pencil. Most work was in the battery box, where a previous owner had left the cells to leak; it was cleaned with gall soap, a brush and abrasive paper. The boards were cleaned with alcohol. Photographs at full size (4000 × 3000 originals) show the main board marked TN-08 TOMY 2E108E01 JAPAN, the D553C 160, a blue transformer and a TO-126 power transistor at the board edge, a lying 3.3 µF 50 V electrolytic, the control board marked 2E108E02 with a W06A diode beside the AC and ground pads, the rubber key pad, and the slide-switch carrier with its contacts.
- ↑ 6.0 6.1 6.2 6.3 Retro Tech Repair, "Fixing a Broken 80s Pacman Game (It Went Horribly Wrong)", YouTube, 13 December 2018, 17:30 (watched 2026-10-18; no transcript available). A non-working Grandstand Munchman bought on eBay ("Pacman - Tomy Munchman Grandstand Electronic Game"). Shown: base screws removed and the board lifted out; about 6.0 V measured on the supply; the TO-126 power transistor tested out of circuit with a 2SD882 data sheet on the bench, and a TO-92 transistor tested with an NPN data sheet; the display lit on the bench after repair and the game playing at the end. The video does not state on screen which part was faulty.
- ↑ 7.0 7.1 NEC Electronics USA, 1982 Microcomputer Catalog, data sheet "μPD552/μPD553 4-bit single chip microcomputers with vacuum fluorescent display drive capability", p. 165, Bitsavers copy on the Internet Archive: PMOS chips in a 42-pin DIP running from a single −10 V supply; 27 output lines "are capable of being pulled to −35V in order to drive Vacuum Fluorescent Displays directly"; the μPD553 has 2000 × 8 ROM.
- ↑ 8.0 8.1 8.2 Handheld Museum forum, "Invaders from Space repair", December 2019 (retrieved 2026-10-18). While repairing an Invader From Space (TDK FCR 400 400 kHz resonator), the owner notes he could not borrow the oscillator from his Munchman because "the Munchman uses a 430 kHz oscillator"; the site administrator notes that the game microcontrollers are specific to each game, so a replacement must come from another copy.
- ↑ 9.0 9.1 9.2 9.3 9.4 Retro Games Now, "Grandstand Munchman 80's handheld review", 17 March 2012, value section updated July 2024 (retrieved 2026-10-18). Collector's review: the Grandstand, Tomy Pac Man and Puck Man versions differ only in the name sticker and packaging; buying checks: "the screens can become scratched and sometimes crack, although smaller scratches can be polished out, cracks cannot be repaired"; the sticker above the screen "can fade, peel or end up missing"; "Check that the game powers up under battery power alone as well as via transformer ... if the power connector is damaged it can lock the game in 'mains power only' mode"; Munchman "always faces to the left" and can only eat going left.
- ↑ 10.0 10.1 10.2 retro_restos, "Munchman Pacman Grandstand VFD Tabletop Game Repair. No power and Scratched Screen Repair", YouTube, 7 April 2023, 21:47 (watched 2026-10-18; no transcript available, facts taken from the frames and the burned-in captions). A Grandstand-branded Munchman that worked on an adaptor but not on batteries. On-screen caption at about 6:10: "I managed to briefly get the batteries to work, but every time I plugged the power jack in, it moved the pin and the batteries wouldn't work again. I ordered a new jack socket". Shown: screws taken out through holes in the base (4:05) and the top shell lifted off (4:22); inside, the VFD in black end blocks over the battery-box moulding, the yellow switch and key carrier screwed down over the boards, and the DC socket in a slot in the case rim with its leads (5:00-5:48); the old socket removed and a new one wired in (7:50-8:40); the smoked window and black panel, held in the top shell by heat-staked pegs, freed with a rotary tool (11:30-11:40), wet-sanded and polished (13:00-16:24), the panel lettering touched up with a white paint marker and the parts refitted with hot glue (16:48-18:30).
- ↑ 11.0 11.1 11.2 11.3 11.4 11.5 analo9 (아날로그 탐구생활), "1981 토미 LSI 휴대용 게임기(팩맨 Pac-Man)", Naver blog, 25 May 2022 (in Korean; retrieved 2026-10-18). Repair of a boxed Tomy Puck Man that would not switch on even from an adaptor: control switches removed and contacts cleaned; supply DC 6 V; piezo buzzer; plastics washed; NEC D553C 4-bit 42-pin microcontroller and NEC VFD; board repaired and tested, display brightness checked; "a pico fuse connected for circuit protection" in the supply lead. Photograph 23 (1280 px) shows the component side legibly: TN-08 TOMY JAPAN 2E108E01; resistor networks EXBR89154M and EXBR86473M; C2785 transistor; 1SS53 and W06C diodes; RD12EB3 zener; SL121J and FZ223Z capacitors; resonator position CSB400P; a 2.2 µF 50 V electrolytic beside the W06C; a grey NTK electrolytic beside the C2785; D553C 160 lot E2464D-218. Photograph 21 shows the ribbon cable from the control board to the main board.
- ↑ 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.
- ↑ 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: the games play and make their sounds without the display or its transformer; displays fade unevenly with heavy use; he has never had a display fail unless the glass was broken.