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Grandstand TV Game 3600 Mk II General Maintenance

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Adman Grandstand 3600 MK II Colour (13)
A TVG-3600 Mk II with its base removed. The board, solder side out, is held to the upper case by two screws; the round opening is where the speaker sits, and the RF lead is clipped to the case at top left.

The Grandstand TV Game 3600 Mk II (front label ADMAN GRANDSTAND TVG-3600 MK II) is a colour Pong console with a light gun, made in Hong Kong and sold in the UK from 1977. It is built around General Instrument's AY-3-8500 game chip, with two CMOS support chips and a colour circuit made from discrete parts on the same board.[1][2][3] The console photographed for Wikimedia Commons still works in colour, and its owner has published notes on opening it.[4] No Grandstand manual, schematic or parts list for the 3600 Mk II has been found. The guidance here comes from those photographs and notes, a second example photographed by the South-West Retro Computing Archive,[5] and General Instrument's 1978 data for the AY-3-8500.

Fault-finding is on Grandstand TV Game 3600 Mk II Troubleshooting Guide; the electrolytic capacitors are listed on Grandstand TV Game 3600 Mk II Capacitor Replacement Guide.

The 3600 Mk II at a glance

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What is inside a TVG-3600 Mk II
Part Detail Source
Game chip General Instrument AY-3-8500, date code 7831 [1]
Support chips Motorola MC14075B (triple 3-input OR); RCA CD4069UBE (hex inverter) [1]
Crystals 2.000000 MHz (game clock) and 4.433618 MHz (PAL colour), both K.D.S, with a green trimmer beside the 4.433618 MHz crystal [1]
RF Screened section on the main board; three adjustable coils in metal cans; fixed RF lead from the rear [1][4]
Supply Six UM-2 (C, LR14) cells, or a 9 V 100 mA adaptor in the left-side socket, centre positive according to the owner [2][4]
Controls Seven slide switches mounted on the board, RESET and SERVE buttons, two plug-in hand controllers, Thundercolt light gun [1][6][7]

Before you start

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  • Remove the six cells and unplug the adaptor, the controllers and the gun.
  • Tools: a cross-head screwdriver, isopropyl alcohol, a soft brush, switch and potentiometer cleaner, and a multimeter. A frequency counter is useful if the colour ever needs attention.
  • The console runs from 9 V. The only mains hazard is an original adaptor: check its case and lead for cracks before plugging it into the wall.

Opening the case

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Adman Grandstand 3600 MK II Colour (15)
The base: two case screws in recesses beside the rubber feet at the top of the picture, the speaker holes, the EXTERNAL POWER marking, the label and the battery cover.

The board, speaker, switches and RF section are all fixed to the upper half of the case. The base comes away.[4][8]

  1. Release the battery cover by its two tabs and take out the cells.[2]
  2. Turn the console over onto a soft cloth. The owner removed four screws to free the base.[4] Two of them are visible in recesses beside the rubber feet at one end of the base; the photograph does not show where the other two are, so look under the battery cover and around the edges before prising anything.[2]
  3. Lift the base away. The solder side of the board faces you, held to the upper case by two screws.[4][8]
  4. The flying leads, including those to the sockets in the sides of the case, are soldered to the board. Photograph them before taking the board out.[8]
  5. The RF lead is held to the case by a plastic clip and a screw. Undo it before lifting the board.[8]

The slide switches, the LEFT PLAYER and RIGHT PLAYER sockets and the speaker are mounted on the board itself; the speaker sits in a round opening in it and sounds through holes in the base.[1][8][2] When you refit the board, line each switch up with its slot in the panel before tightening the two screws.

Cleaning

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  • Wipe the case with a damp cloth and a little washing-up liquid. Keep water away from the printed panel with its game key, and from the base label.
  • Clean the board with isopropyl alcohol and a soft brush. On the photographed board there are light-coloured deposits in the corner beside the blue electrolytic marked "SE 10 V";[1] clean them off and look at the tracks and the capacitor's leads underneath.
  • Clean the seven slide-switch contacts, the two pushbutton contacts and the four sockets (two controller, one power, one pair for the gun).

Power: cells, adaptor and polarity

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Adman Grandstand 3600 MK II Colour (6)
The left side of the case and its single socket for an external 9 V supply.
  • Six 1.5 V C cells (UM-2, LR14) go in the compartment behind the battery cover.[2][4]
  • The base label asks for a 9 V adaptor rated 100 mA. The socket is on the left side of the case; the base marks it EXTERNAL POWER.[2][9]
  • The label gives no polarity. The owner of the photographed console gives it as centre positive and ran the console that way.[4] Measure the socket against the battery terminals before trusting that, and measure any adaptor before connecting it.
  • The Grandstand Universal Mains Adaptor was sold for Grandstand's handheld and tabletop games, with a polarity switch and an output of 6 to 9 V.[10] The tabletop game leaflets tell owners to set its switch to negative,[11] so check the switch, and the plug with a meter, before using one on a 3600 Mk II.
  • Inside, the AY-3-8500 itself runs from +6 to +7 V and must never see more than +12 V on any pin.[12] The board brings the 9 V supply down for the chip; how it does so has not been traced.

Take the cells out for storage. Leaking C cells corrode the springs and can run onto the leads to the board.

Controllers, buttons and switches

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Hand controllers

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The two grey hand controllers are separate from the console and plug into the LEFT PLAYER and RIGHT PLAYER sockets on the panel with jack plugs.[7][6][4] Each turns a potentiometer that sets its bat's height through an R-C network on the AY-3-8500's bat inputs; GI's reference design uses 1 MΩ.[12] The values in the Grandstand controllers have not been read.

  • A jumping bat usually means a dirty potentiometer track. Open the controller, spray potentiometer cleaner into the track and turn the knob end to end.
  • Because both controllers plug in, swapping them between the sockets tells a controller fault from a console fault at once.
  • Clean the jack plugs and the board-mounted sockets, and check each lead where it enters the controller.

Slide switches and pushbuttons

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POWER, BALL SERVE, BALL SPEED, BALL ANGLE, PLAYER SIZE and the two GAME SELECT switches (A/C and B/D) are slide switches soldered to the board, and their levers come up through the panel.[6][1] On the AY-3-8500 every setting and every game is chosen by connecting an input to ground, and GI specifies no more than 1 kΩ of contact resistance for a closed contact.[12] A dirty switch that reads a few kilohms may not register. Spray a little switch cleaner into each switch and work it a dozen times, then check the closed contact with a meter.

The RESET and SERVE buttons sit above a metal plate on the board, marked V-7, which carries two spiral spring contacts.[1] These appear to be the button contacts; clean them if a button stops working.

Light gun

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The 3600 Mk II was supplied with a pistol marked THUNDERCOLT Super Marksman 304.[7][3] Its lead ends in a twin plug with two jack pins of different sizes, which fits the pair of sockets (a jack and a mini-jack) on the right side of the case.[7][13][4] The target games only appear once the gun is plugged in.[4]

  • Keep the gun's lens clean and check the trigger switch and the lead.
  • Light guns of this period detect the light from a cathode-ray tube television. Test the gun on a CRT set, not a flat-panel one.
  • Prinztronic sold a Thundercolt TV Game Pistol for its own consoles;[14] no source says whether it works with the Grandstand.

RF output and the colour adjustments

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  • The RF lead is fixed and leaves the rear of the case.[4] The label does not give a channel. GI's application note gives UHF channel E36 as one of the two standard modulator channels for these games, so start the search there on an analogue UHF tuner.[15][2]
  • The board carries a green trimmer beside the 4.433618 MHz crystal and three adjustable coils in metal cans.[1] GI's application note asks for a PAL game's colour subcarrier to be within ±50 Hz of 4.433619 MHz, because an average colour television only locks within about 400 Hz.[15] Do not turn the trimmer or the coils to "improve" a picture. If one must be moved, mark its position first and measure the subcarrier with a frequency counter.
  • The game clock matters too. GI warns that on PAL televisions with a delay line, a wrong 2 MHz clock makes picture detail appear doubled.[15]

Wearing parts

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What wears on a 3600 Mk II
Part Why Check
Slide switches Open contacts; need under 1 kΩ when closed[12] Clean; measure the closed contact
Controller potentiometers Dirty tracks make the bat jump Clean; swap controllers to compare
Controller, power and gun sockets Plugged and unplugged often Clean; check the solder joints of the board-mounted sockets
RESET and SERVE contacts Spring contacts on a plate[1] Clean
Electrolytic capacitors Five on the board, all from the late 1970s[1] See Grandstand TV Game 3600 Mk II Capacitor Replacement Guide
Battery springs Corrode if cells are left in Remove cells for storage

Test points

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The AY-3-8500's pins as given in GI's 1978 data. Measure with the console running and the meter's negative lead on pin 2.[12]

AY-3-8500 test points
Pin Function Expected
2 VSS (ground) Reference
4 VCC +6 to +7 V
17 Clock input 2.012160 MHz ±1%
16 Sync output Pulses while running
3 Sound output 32 ms tone bursts: 976 Hz on a hit, 488 Hz off a wall, 1.95 kHz on a score
25 Reset Pulled to ground only while RESET is pressed
26, 27 Shot and hit inputs Positive pulses from the gun circuit

Storage

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  • Remove the cells.
  • Store the controllers and the gun unplugged, with their leads loosely coiled.
  • Keep the console dry and out of the sun.

Preventive maintenance checklist

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  1. Take out the cells and look at the springs.
  2. Measure the adaptor and the side socket for voltage and polarity before connecting them.
  3. Open the base, check the electrolytics and clean any deposits from the board.
  4. Clean the seven slide switches, the RESET and SERVE contacts and the four sockets.
  5. Clean both controller potentiometers and swap the controllers to compare them.
  6. Plug in the gun and check that the target games appear.
  7. Tune an analogue television and check the colour, the scores and both bats.
  8. Measure pins 4 and 17 of the AY-3-8500.
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References

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  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 Photograph by José Antonio Ortigueira Amor, File:Adman Grandstand 3600 MK II Colour (14).jpg (CC BY 4.0, from Wikimedia Commons; larger copy on the owner's blog), examined at full size: component side of the board with "GI AY-3-8500 7831 TAIWAN", Motorola "MC14075B", "CD4069UBE RCA 827", crystals "2.000000 K.D.S" and "4.433618 K.D.S", a green trimmer beside the 4.433618 MHz crystal, a screened section at one end holding a transistor, an air-wound coil and the RF lead, three adjustable coils in metal cans, a "TOA 8 Ω" speaker, seven slide switches along one edge, two board-mounted sockets, a metal plate marked "V-7" carrying two spiral spring contacts, and five electrolytic capacitors: a blue one marked "220 µF" on the switch edge, two blue ones at the end beside the 2 MHz crystal, a blue one marked "SE 10 V" in the corner below it, and a small light-blue one beside the green trimmer. Light-coloured deposits are visible in the corner near the "SE" capacitor.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Photograph by José Antonio Ortigueira Amor, File:Adman Grandstand 3600 MK II Colour (15).jpg (CC BY 4.0, from Wikimedia Commons), examined at full size: the base, with the label "COLOR TV-GAME / PATENTS BRITISH NO: 1268821 AND 1328223 AND IN OTHER 18 COUNTRIES / BATTERY: UM-2 x 6 OR AC ADAPTOR (9V / 100 MA) / SERIAL NO: 070957 / MADE IN HONG KONG", a moulded "EXTERNAL POWER" marking with an arrow at one side, a pattern of holes over the speaker, a battery cover with two tabs, two rubber feet at one end with a case screw in a recess beside each, and two moulded feet at the other end.
  3. ↑ 3.0 3.1 Centre for Computing History, "Adman Grandstand 3600 Mk II TV Game", CH39823 (retrieved 2026-10-18): "A four-game, colour, Pong console from Adman Grandstand. Supplied with light gun."; dated 1977.
  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 José Antonio Ortigueira Amor, "Adman Grandstand TV Game 3600 MK II Colour (1978)", Retro Ordenadores Orty (collector's blog, in Spanish), 23 November 2023 (retrieved 2026-10-18). The owner's description of his console: General Instrument AY-3-8500 with a Motorola MC14075B and an RCA CD4069UBE; two separate hand controllers that plug into LEFT PLAYER and RIGHT PLAYER sockets near the front edge; a socket on the left side for an external 9 V DC supply, centre positive; a jack and a mini-jack on the right side for the light gun; the RF lead leaves the rear; six 1.5 V C (LR14) cells in an internal compartment reached through the lower case; four screws hold the lower case, and removing it exposes the back of the board, which is held to the upper case by two screws; the console works and gives a colour picture; only the four bat-and-ball games are available until the light gun is plugged in, when the target games appear; the 3600 series had three models (TVG 3600, Mk II and Mk III).
  5. ↑ South-West Retro Computing Archive (University of Plymouth), "Adman Grandstand TVG-3600 MKII" (retrieved 2026-10-18): photographs of a second, boxed TVG-3600 Mk II with its hand controllers, the two sockets in the side of the case, and a base label with the same wording as the Commons console's, serial number 40213.
  6. ↑ 6.0 6.1 6.2 Photograph by José Antonio Ortigueira Amor, File:Adman Grandstand 3600 MK II Colour (3).jpg (CC BY 4.0, from Wikimedia Commons): the panel, with POWER (OFF/ON), BALL SERVE (MANUAL/AUTO), BALL SPEED, BALL ANGLE and PLAYER SIZE under AMATEUR and PROFESSIONAL, GAME SELECT switches A/C and B/D, the game key (TENNIS A-B, FOOTBALL A-D, SQUASH B-C, PRACTICE C-D, TARGET 1 B, TARGET 2 D), RESET and SERVE buttons, and the LEFT PLAYER and RIGHT PLAYER sockets.
  7. ↑ 7.0 7.1 7.2 7.3 Photograph by José Antonio Ortigueira Amor, File:Adman Grandstand 3600 MK II Colour (2).jpg (CC BY 4.0, from Wikimedia Commons), examined at full size: the console with its box ("ADMAN GRANDSTAND TV GAME 3600 MK II", "COLOUR"), the two grey cylindrical hand controllers on grey leads ending in jack plugs, and the light gun marked "THUNDERCOLT Super Marksman 304", whose lead ends in a twin plug with two jack pins of different sizes.
  8. ↑ 8.0 8.1 8.2 8.3 8.4 Photograph by José Antonio Ortigueira Amor, File:Adman Grandstand 3600 MK II Colour (13).jpg (CC BY 4.0, from Wikimedia Commons; larger copy on the owner's blog), examined at full size: the upper case seen from below with the base removed; the solder side of the board, held by two screws; the RF lead held to the case by a plastic clip and screw; a round opening in the board where the speaker sits; coloured flying leads soldered to the board.
  9. ↑ Photograph by José Antonio Ortigueira Amor, File:Adman Grandstand 3600 MK II Colour (6).jpg (CC BY 4.0, from Wikimedia Commons): the left side of the case, with a single socket, beside the LEFT PLAYER end of the panel.
  10. ↑ Handheld Museum, "Grandstand Universal Mains Adapter" (retrieved 2026-10-18). Collector's entry: model UGT, "AC adapter sold by Grandstand in England/U.K. for their handheld/tabletop games", for 240 V mains, with a switch that toggles the polarity and turns the output off; output 6-9 V DC at 1.5 VA.
  11. ↑ Grandstand, Astro Wars instruction leaflet (Adam Leisure Group, 1981), p. 2: the game "can be operated from the mains with a GRANDSTAND Universal Mains Adaptor (not included). Set polarity switch to negative polarity." Hosted here as File:Grandstand Astro Wars Instructions.pdf.
  12. ↑ 12.0 12.1 12.2 12.3 12.4 General Instrument Corporation, GIMINI TV Game Circuits, January 1978, pp. 4-7, PDF hosted by Pong-Story (retrieved 2026-10-18). AY-3-8500 data sheet: pin 2 VSS, pin 4 VCC; standard conditions VCC +6 to +7 V; -0.3 to +12 V maximum on any pin; supply current 40 mA typical, 60 mA maximum at +7 V; clock input pin 17, 2.012160 MHz ±1% (1.99 to 2.03 MHz); sound output pin 3 (32 ms tones: 976 Hz hit, 488 Hz boundary, 1.95 kHz score); ball angles pin 5, ball speed pin 7 (open 1.3 s, grounded 0.65 s to cross the screen), manual serve pin 8 (grounded for automatic serving; when open the game stops after each score and a serve is made by momentarily grounding the pin), bat size pin 13, game select pins 18 to 23 (rifle 1, rifle 2, tennis, soccer, squash, practice), each grounded to select; reset pin 25, momentarily grounded; shot and hit inputs pins 26 and 27, positive pulses from monostables in the rifle circuit; sync output pin 16; bat inputs pins 11 and 12 fed by R-C networks, "Use a 10K resistor in series with each pot"; control inputs have on-chip pull-ups and need a contact resistance of no more than 1 kΩ to VSS; reference circuits with 1 MΩ bat potentiometers and 0.1 µF bat capacitors.
  13. ↑ Photograph by José Antonio Ortigueira Amor, File:Adman Grandstand 3600 MK II Colour (5).jpg (CC BY 4.0, from Wikimedia Commons): the right side of the case, with a small and a larger socket side by side, beside the RIGHT PLAYER end of the panel.
  14. ↑ Centre for Computing History, "Prinztronic Thundercolt TV Game Pistol", CH33635 (retrieved 2026-10-18): a Thundercolt TV game pistol sold by Prinztronic for its Videosport 600, Videosport 800 Colour and Tournament Colour Programmable 2000 consoles, with a barrel attachment.
  15. ↑ 15.0 15.1 15.2 General Instrument Corporation, GIMINI TV Game Circuits, January 1978, pp. 73-83: Astec International application notes on PAL colour for the AY-3-8500, PDF hosted by Pong-Story (retrieved 2026-10-18). The 2.0 MHz game clock must be at exactly the right frequency, because on PAL receivers with a delay line a wrong clock makes picture detail appear doubled; the 4.433618 MHz subcarrier oscillator needs careful alignment and stability. "An alternate colour encoding system" uses only two CMOS packages, a 4069 hex inverter and a 4075 triple 3-input OR gate, with one transistor, ahead of an Astec colour encoder and modulator; its subcarrier "should be aligned to 4.433619MHz with a maximum tolerance of ±50Hz", because the pull-in range of the average colour television is only about 400 Hz; standard modulators are tuned to channel E3 (VHF) or E36 (UHF).


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