Grandstand Model 5000 Capacitor Replacement Guide

The board of a Grandstand 4600, a six-game console in the same style of case as the 5000; this is not a 5000 board. No photograph of the inside of a Grandstand 5000 has been published.

The Grandstand Model 5000 (panel name GRANDSTAND 5000 COLOUR) is a ten-game colour TV game dated 1977 by the Centre for Computing History: six bat-and-ball and target games, and four motorcycle games played with a separate throttle controller. No photograph of its board or base, no parts list and no schematic has been published, so none of its capacitors is known. Its games point to two General Instrument chips, and GI's 1978 data shows what each needs from the capacitors around it. The nearest photographed board is the Grandstand Model 4600's, in the same style of case. Below are what is known of the 5000, GI's values for the two chips, the 4600's board for comparison, and how to open, record and recap a 5000.

Care is on Grandstand Model 5000 General Maintenance; symptoms are on Grandstand Model 5000 Troubleshooting Guide.

What is known for the 5000

The 5000's throttle controller (left), a white cylinder with a brown knob, and its light gun. Both plug in with mono mini-jack plugs.

• The panel's GAME switch changes between PADDLE RIFLE and CYCLE games, and a SPEED/CYCLE switch is marked EASY and HARD for the cycle games.
• The six PADDLE RIFLE games (practice, squash, soccer, tennis and two targets) are the AY-3-8500's six; the four CYCLE games (Motor Cross, Enduro, Drag Race and Stunt Cycle) are the four of GI's AY-3-8760 "Cycle" chip, whose PRO/AM input selects a hard or easy mode. Pong-Story lists the AY-3-8765 as the PAL version of the cycle chip. Neither chip has been seen in a photograph of a 5000.
• The throttle is a separate white controller on a lead with a mono mini-jack plug.
• No base label has been published, so the supply rating and polarity are not known. The 4600 and 6000, in the same style of case, are labelled for six UM-2 cells or a 9 V DC 100 mA adaptor.
• No capacitor value, position or failure has been reported for a 5000.

What the two game chips need

GI's 1978 data gives these capacitors around the two chips. They are GI's reference values, not readings from a 5000:

Capacitors in General Instrument's circuits for the 5000's two likely chips

Chip and function	GI's part	Electrolytic?	Source
AY-3-8500, supply (pin 4 to pin 2)	10 µF	Yes
AY-3-8500, each bat input	0.1 µF, with the bat potentiometer and 10 kΩ	No
AY-3-8500, sound driver	0.2 µF with 15 kΩ at the transistor's base	No
AY-3-8760, power-on reset (pin 12)	0.1 µF to VSS, with 100 kΩ to VDD	No
AY-3-8760, sound (pin 13)	0.1 µF across the speaker, driven by a PNP transistor, with a 500 Ω volume control	No
AY-3-8760, throttle (pin 18)	An oscillator of 50 to 250 kHz; its parts are not given	Not shown

The power-on reset capacitor matters on a console of this kind: GI's cycle chip relies on its 100 kΩ and 0.1 µF network to reset itself when power is applied. GI gives the AY-3-8500 a supply of +6 to +7 V; it prints no supply voltage for the AY-3-8760 in the same catalogue.

The 4600 board, for comparison

The 4600's board, in the same style of case, has C-numbers printed beside its parts and about ten electrolytics, of which two markings can be read: C38 is 10 µF and C37 is rated 16 V. The full reading is on Grandstand Model 4600 Capacitor Replacement Guide. The 5000's cycle games, throttle input and GAME switch have no counterpart on the 4600, so its board is likely to differ at least in those parts; whether its supply and RF sections match the 4600's is not known.

Signs of trouble

• Bulging, leaking or split capacitors, or deposits round their leads. The 4600 in the same style of case has brown deposits on and around several parts, cause unknown.
• Cycle games that misbehave from switch-on. After the GAME switch, the game slider and the throttle plug, the reset network on the cycle chip (100 kΩ and 0.1 µF in GI's circuit) is one of the parts to check.
• Hum bars, a rolling picture or colour that comes and goes, once the supply and the television's tuning have been checked. See Grandstand Model 5000 Troubleshooting Guide and Capacitor Failure Symptoms.
• Leaked cells: see Battery Explosion, Capacitor or Corrosion Damage.

Recording a 5000 board

No 5000 board has been described in public. When you open one:

1. Photograph the base label first: the 5000's supply rating has not been published.
2. Photograph both sides of the board, and every wire to the pods, the throttle and gun sockets and the DC socket.
3. Record both chips' full markings. The game list suggests an AY-3-8500 and an AY-3-8760 or AY-3-8765, but nobody has confirmed it.
4. Record each electrolytic's C-number (if the board has them, as the 4600's does), capacitance, voltage, maker, size and stripe side, and note which chip it sits beside.
5. Put each removed part on a capacitance or ESR meter and write the result beside its marking.

Opening and recapping

No account of opening a 5000 has been published. Its case style matches the 4600, which opens like this:

1. Take out the cells, unplug the adaptor, the throttle and the gun, and lift both pods out of their bays.
2. Slide off the battery cover. On the 4600 two case screws are inside the battery compartment and two more sit beside the feet at the other end; find all four on your 5000 before prising anything.
3. Lift the base away. On the 4600 the board is fixed to the upper case by five screws. Photograph every wire before lifting the board.
4. Take the capacitors out one by one, recording each first. Fit a 105 °C replacement of the same capacitance, an equal or higher voltage, the same lead spacing and the same polarity, and no taller than the original, so the board still seats under the panel.
5. Refit the board with the switches and the game slider in their slots, then the base.

Recommended tools and parts

• Iron with temperature control, braid or a desoldering pump, flux, and isopropyl alcohol.
• Multimeter, a capacitance or ESR meter, and if possible a frequency counter for the throttle oscillator.
• Current-production 105 °C radial electrolytics (Nichicon, Panasonic, Rubycon or similar), in the values found on the 5000's board.
• A current-limited bench supply, set to the voltage and polarity on your 5000's own label. See also Recommended Tools.

Checks after recapping

After recapping a 5000

Check	Expected	Source
Supply	As on your console's base label; the 4600 and 6000 labels give 9 V DC 100 mA
AY-3-8500 pin 4 to pin 2, if fitted	+6 to +7 V; 60 mA at most at +7 V
AY-3-8760 or 8765 pin 28 (VDD) to pin 14 (VSS), if fitted	No figure published by GI; record what you measure
PADDLE RIFLE games	Bats move with the pods; SERVE and GAME RESET work; target games with the gun on a CRT set
CYCLE games	The bike starts from rest and its speed follows the throttle; the EASY/HARD switch changes the game

Related pages

• Grandstand Model 5000
• Grandstand Model 5000 General Maintenance
• Grandstand Model 5000 Troubleshooting Guide
• Grandstand Model 4600 Capacitor Replacement Guide, in the same style of case
• Grandstand Model 6000 Capacitor Replacement Guide, in the same style of case