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Magnavox Odyssey 3000 Capacitor Replacement Guide

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Magnavox Odyssey 3000 BH7514 board layout (SM 6509)
Magnavox's drawing of the Odyssey 3000 main board, XM-050-C. C7 (100 µF) is at top left beside D1, C8 (220 µF) beside Q1 and C6 (220 µF) beside RFC3 (Service Manual No. 6509, p. 6509-2).

The Magnavox Odyssey 3000 (BH7514) has four aluminium electrolytic capacitors: three around the voltage regulator on the main board and one on the supply to the modulator board. Magnavox's Service Manual No. 6509 lists them in the parts list, shows them on the schematic and marks them on the two board drawings.[1][2][3] For the general signs of a failed capacitor see Capacitor Failure Symptoms.

Before replacing anything

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The console runs from six C cells or an AC to DC adaptor, so there is no mains voltage inside it.[4] Magnavox's manual names no capacitor as a known fault. Measure the regulator first, with the adaptor connected: 9.8 V at the collector of Q1, 7.8 V at its base and 7.1 V at its emitter.[2]

Electrolytic capacitors

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Odyssey 3000 (BH7514) electrolytic capacitors
Ref Value Rating (parts list) Rating (schematic) Part no. Circuit (schematic) Board
C6 220 µF 16 V 16 V 27X109-2215 Regulator reference: the base of Q1, fed through R3 (680 Ω) Main, beside RFC3
C7 100 µF 10 V 10 V 27X109-1210 Across the 7.5 V zener D1 at the base of Q1 (7.8 V) Main, beside D1
C8 220 µF 10 V 10 V 27X109-1210 Regulated 7.1 V output at the emitter of Q1, U1 pin 4 Main, beside Q1
C18 10 µF 25 V 16 V 27X109-1010 Supply to the modulator, after the choke RFC5 Modulator, beside RFC5

[1][2][3]

Two points in the manual disagree. The parts list gives C7 (100 µF) and C8 (220 µF) the same part number, 27X109-1210, so the number is wrong for one of them; go by the value printed beside each part. The parts list rates C18 at 25 V and the schematic at 16 V; a 25 V part suits either.[1][2]

C6 and C7 are on the same point, the base of Q1; C6 is drawn at the R3 end and C7 beside the zener.[2] The highest voltage Magnavox gives anywhere on the board is 9.8 V, at the collector of Q1 with the adaptor connected; 16 V parts give a margin over that in all four positions.[2]

Other capacitors

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Capacitors not listed separately in the parts list are 10 %, 25 V parts unless the schematic says otherwise; the schematic's own note gives 10 %, 500 V.[1][2]

  • C10 and C11 (0.1 µF, 250 V) are on the player control inputs, U1 pins 12 and 11.[2]
  • C4 (91 pF) is in the 2 MHz oscillator with the coil L1. Disturbing it means resetting L1 for 2.01 MHz.[2][4]
  • The modulator uses small ceramics (C15 3 pF, C20 36 pF NPO, C21 and C22 7 pF) around the RF oscillator Q4 and the trimmer CT1. Leave them alone during a recap, or repeat the channel 3 adjustment afterwards.[1][4]
  • The parts list prints C5 twice, as 0.022 µF and as 0.02 µF; the schematic gives C5 as 0.02 µF and C24 as 0.022 µF.[1][2]

Procedure

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  1. Take out the cells and unplug the adaptor and both player controls.
  2. Reach the main board and the modulator board as described on the maintenance page, labelling any wires you unsolder.
  3. Note the polarity of each capacitor; both board drawings mark the positive lead.[3][2]
  4. Fit 220 µF in C6 and C8, 100 µF in C7 and 10 µF in C18, each rated at least as high as the table.[1]
  5. Clean off the flux and check 7.8 V at the base and 7.1 V at the emitter of Q1.[2]
  6. Check the picture on channel 3 and the sound.[4]
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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Magnavox, Service Manual No. 6509, November 1977, p. 6509-5: BH7514 replacement parts list (coils, capacitors with type, value, rating and part number, controls and switches, semiconductors, cords, speaker and instruction booklet IB3280-1) and the cabinet replacement parts list. Hosted as File:Magnavox Odyssey 3000 Service Manual 6509.pdf.
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 Magnavox, Service Manual No. 6509, November 1977, pp. 6509-3 and 6509-4: BH7514 schematic diagram with the regulator voltages, U1 marked AY-3-8500-1, the U1 voltage chart, the notes (including the triangle marking parts not on the P.C. board and voltages taken with a VTVM on the AC to DC adaptor), the modulator schematic and the modulator P.C. board (XJ-012-B). Hosted as File:Magnavox Odyssey 3000 Service Manual 6509.pdf.
  3. ↑ 3.0 3.1 3.2 Magnavox, Service Manual No. 6509, November 1977, p. 6509-2: main P.C. board, component view (board XM-050-C), with the off-board jack, battery, power switch, slide switches, game selector, push buttons and player controls. Hosted as File:Magnavox Odyssey 3000 Service Manual 6509.pdf.
  4. ↑ 4.0 4.1 4.2 4.3 Magnavox Consumer Electronics Company, Service Manual No. 6509: BH7514 Odyssey, first issue, November 1977, p. 6509-1: general information (6 C cells or an optional AC to DC voltage adaptor; Tennis, Hockey, Smash and Practice; Amateur and Professional settings for ball speed, ball angle and player size; manual or automatic serve; on-screen scoring; play to 15; reset to 0-0 with a random serve; three tones), the service adjustments (2 MHz oscillator with L1; channel 3 RF oscillator with CT1; channel 4 not adjustable) and typical operation (channel switch in the battery compartment; detachable player controls). Hosted as File:Magnavox Odyssey 3000 Service Manual 6509.pdf.


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