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Magnavox Odyssey 4000 General Maintenance

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Magnavox Odyssey 4000 BH7511 board layout (SM 6508)
Magnavox's drawing of the Odyssey 4000 (BH7511) main board, 703931-1. The supply parts (Q1, Z1, L1, C1, C3, C4) are at top left, the clock (X1, C10) beside IC2, and the hue and video level controls R4 and R5 at the bottom (Service Manual No. 6508, p. 6508-7).

The Magnavox Odyssey 4000 (BH7511) dates from 1977 and runs only from a 9 V adaptor.[1] Magnavox's Service Manual No. 6508 gives four adjustments: the 3.58 MHz colour clock, the channel 3 and 4 RF oscillator, the video level and the hue.[2] Routine care is the adaptor and its socket, four slide switches, the channel switch and the two joystick hand controls with their cables. Faults are covered on Magnavox Odyssey 4000 Troubleshooting Guide and the four electrolytic capacitors on Magnavox Odyssey 4000 Capacitor Replacement Guide.

Opening the console

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Magnavox's booklet describes opening the cabinet to reach the channel switch:[3]

  1. Unplug the adaptor and both hand controls.
  2. Turn the console upside down and find the screw in the centre of the cabinet back.
  3. Press down gently while turning the screw about half a turn anticlockwise.
  4. Take hold of both sides of the cabinet and lift it off. The channel switch is at the left of the board.

The parts list gives this fixing as a cover holding stud (732953-2) with a spring lock nut (103235-1) and an O-ring retainer (103082-4).[4] The chips and crystal sit under metal shields: an IC shield top cover (733393-1), a crystal circuitry shield (733392-1) and a bottom cover shield (733394-1). Refit them after any work on the board.[4]

Power

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  • The adaptor is Magnavox part AG9004-BK01, rated 9 V DC at 100 mA, and plugs into J1 (181139-4).[1][4] The service manual places the socket on the back of the main unit; the booklet on the left centre of the control board.[1][3]
  • From J1 the supply passes through the choke L1 (1 mH) and the RESET/ON/OFF switch S4 to the regulator Q1.[5]
  • Magnavox took its voltage readings with a VTVM and the adaptor input held at 9 V by a regulated supply. Use a regulated 9 V supply when comparing your readings with the charts.[5]

Supply checks

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Odyssey 4000 supply readings (schematic and voltage charts, 9 V regulated input)
Point What it is Expected
Q1 collector Supply after S4 8.3 V
Q1 base Held by the zener Z1 6.9 V
Q1 emitter Regulated supply 6.2 V
IC1 pin 16 IC1 VCC 6.2 V
IC2 pin 22 IC2 VCC 6.2 V
IC1 pin 1, IC2 pin 1 Ground 0 V

[5][6]

Switches

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Odyssey 4000 switches (parts lists, pp. 6508-3 and 6508-6)
Ref Function Magnavox part
S1 Game select, eight positions 160592-1
S2 Ball speed 160546-3
S3 Skill 160546-7
S4 On/off/reset 160546-5
S1 (RF module) Channel select 160556-2

[4][7]

Each setting switch takes an IC1 input to 0 V in one position: S4 at RESET (pin 18), S3 at Professional (pin 19) and at Handicap or Professional (pin 20), and S2 at Slow (pin 21). If a setting has no effect, check that the pin changes between 6.2 V and 0 V as the switch is moved.[6]

Hand controls

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Each hand control holds a joystick that turns two controls through a nylon crank: R1 for horizontal movement (150 kΩ, 220311-16) and R2 for vertical (500 kΩ, 220311-15). The action button presses a momentary switch S1 made of a leaf contact (160599-2) and a post contact (160599-1), returned by a spring (733305-1).[7]

  • The hand control board, 211156-2, has a five-pin connector J1 (181253-5). The cable assembly with its connectors is 702597-1, and it plugs into the console at P2 (right) or P3 (left).[7][4][5]
  • Check each control with the voltage chart: the vertical inputs, IC1 pins 11 (left) and 15 (right), should swing between 1.7 V and 4.7 V as the joystick moves up and down; the horizontal inputs, pins 10 (left) and 14 (right), sit at about 6.1 V and vary slightly; the serve inputs, pins 12 (left) and 17 (right), read 6.2 V and fall to 0 V when the action button is pressed.[6]
  • The joystick moves the player in the same direction only when the hand control is held with its coloured button at the top left.[3]

Service adjustments

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Set the clock and the video level before the hue; Magnavox says the hue adjustment should be made only after those two.[2]

3.58 MHz clock

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  1. Connect a high impedance frequency counter to IC2 pin 6.
  2. Adjust the trimmer C10 (2–22 pF) for 3,579,545 Hz ± 50 Hz.[2][4]

Pin 6 is a buffered output, so the counter does not change the reading, although the picture may be disturbed while the counter is connected.[2]

Channel 3 and 4 RF oscillator

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  1. Connect the console to a working television and turn off the television's automatic fine tuning (AFT).
  2. Set the television and the console's channel switch, on the RF modulator assembly, to channel 3.
  3. Adjust L3 for the best picture.
  4. Switch the television and the console to channel 4.
  5. Adjust the trimmer C5 for the best picture.
  6. Repeat steps 2 to 5 until the picture is equally good on both channels.[2]

Video level

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  1. Connect an oscilloscope to the wiper of the video level control R5.
  2. Adjust R5 for a nominal 0.8 V peak to peak.[2]

Hue

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  1. Tune the television to a local station and set its controls for a good colour picture.
  2. Connect the console and set the game switch to Tennis.
  3. Adjust the hue control R4 for a green background with yellow to orange field lines.
  4. Step through the other games and check the background colours.[2]
Background colours after the hue adjustment (p. 6508-2)
Games Background
Tennis and Soccer Green
Hockey and Gridball Blue
Basketball Practice and Smash Practice Cyan
Basketball and Smash Magenta

[2]

Magnavox notes that the colours vary with the television's own control settings.[2]

Television connection

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  • Connect the lead from the antenna-game switch to the television's 300 Ω VHF terminals, and move the switch fully to GAME or fully to TV; left in the middle it does not work properly.[3]
  • A round 75 Ω aerial cable needs a 75 Ω to 300 Ω balun.[3]
  • The channel switch is set to channel 3 at the factory. Use channel 4 where a station broadcasts on channel 3.[3]
  • Magnavox warns that a game pattern left on screen for more than six to eight hours continuously can burn into the picture tube.[3]

Preventive maintenance checklist

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  1. Check the adaptor's output and the J1 socket; the console needs 9 V.[1]
  2. Measure 6.2 V at the emitter of Q1 and at IC1 pin 16.[5][6]
  3. Work the four slide switches and check IC1 pins 18 to 21 against the chart.[6]
  4. Check both hand controls and their cables at IC1 pins 10 to 12, 14, 15 and 17.[6]
  5. Check the clock at IC2 pin 6 (3,579,545 Hz ± 50 Hz) and the background colours.[2]
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References

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  1. ↑ 1.0 1.1 1.2 1.3 Magnavox Consumer Electronics Company, Service Manual No. 6508: BH7511 Odyssey, second issue, January 1978, p. 6508-1: general information (AC to DC 9 volt 100 mA adaptor; the eight games; the three-position skill switch with Amateur, Professional and Handicap; on-screen scoring from 0 to 15; full colour on a colour television; hand controls with joysticks on cables; Fast and Slow ball speed; sound and deflection; Reset/On/Off switch; manual serve with the action buttons) and typical operation (channel switch on the RF modulator box; adaptor socket on the back of the main unit; light green Tennis background). Hosted as File:Magnavox Odyssey 4000 Service Manual 6508.pdf.
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 Magnavox, Service Manual No. 6508, January 1978, p. 6508-2: operation continued (spring-loaded Reset; serving with the red and blue action buttons; five serves in Tennis; serving stops at 15 until Reset), the service adjustments (3.58 MHz clock with C10 at IC2 pin 6; channel 3 and 4 RF oscillator with L3 and C5; video level with R5 for 0.8 V peak to peak; hue with R4 and the four background colours) and the top view of the BH7511. Hosted as File:Magnavox Odyssey 4000 Service Manual 6508.pdf.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Magnavox Consumer Electronics Company, Odyssey 4000 Installation and Game Rules, IB 3287-1: the notice on screen burn, the antenna-game switch, game cord, AC adaptor and channel switch, with the bottom cabinet's centre screw (p. 1); the Reset/On/Off, game, skill and ball speed switches, scoring, serving, player controls and action buttons (p. 2); playing all games, Soccer, Tennis and Hockey (p. 3); Basketball, Basketball Practice, Gridball, Smash and Smash Practice (p. 4). Hosted as File:Magnavox Odyssey 4000 Installation and Game Rules IB3287-1.pdf.
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Magnavox, Service Manual No. 6508, January 1978, p. 6508-6: BH7511 replacement parts list (coils, capacitors with type, value, rating and part number, controls and switches, semiconductors and integrated circuits, connectors, shields, RF modulator assembly, speaker, cabinet parts, hand control cable and AC adaptor). Hosted as File:Magnavox Odyssey 4000 Service Manual 6508.pdf.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 Magnavox, Service Manual No. 6508, January 1978, p. 6508-4: BH7511 schematic diagram, with the power input, the regulator Q1 and its voltages, IC1 and IC2 with their pin functions, the hand control connections, the sound amplifier Q2, and the notes (voltages taken with a VTVM and the adaptor input held at 9 V by a regulated supply). Hosted as File:Magnavox Odyssey 4000 Service Manual 6508.pdf.
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Magnavox, Service Manual No. 6508, January 1978, p. 6508-5: IC1 and IC2 voltage charts with notes 1 to 14, and the RF modulator schematic. Hosted as File:Magnavox Odyssey 4000 Service Manual 6508.pdf.
  7. ↑ 7.0 7.1 7.2 Magnavox, Service Manual No. 6508, January 1978, p. 6508-3: RF modulator P.C. board and replacement parts list, hand control P.C. board (211156-2) and replacement parts list, and the antenna switch box parts list. Hosted as File:Magnavox Odyssey 4000 Service Manual 6508.pdf.


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