Magnavox Odyssey 300 Capacitor Replacement Guide
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The Magnavox Odyssey 300 (BG7500) has only three electrolytic capacitors, all 470 µF 16 V parts on the supply side of the board. Magnavox's Service Manual No. 6504 gives their values, ratings and part number in the parts list, shows them on the schematic and marks them on the board drawing.[1][2][3] For failure signs in general see Capacitor Failure Symptoms.
Before replacing anything
[edit | edit source]The console runs from six C cells or a 9 V adaptor, so there are no mains voltages inside it.[4] Magnavox's documents name no capacitor as a known fault. Check the supply first: 9 V at the collector of the regulator Q1 and 6.4 V at its emitter and IC1 pin 4.[2]
Electrolytic capacitors
[edit | edit source]| Ref | Value | Rating | Magnavox part no. | Circuit (schematic) | Beside (board drawing) |
|---|---|---|---|---|---|
| C1 | 470 µF | 16 V | 270109-5215 | Switched 9 V supply after the power switch S1, at the collector of regulator Q1 | Battery terminals W5 to W9 |
| C2 | 470 µF | 16 V | 270109-5215 | 9 V input from the battery or adaptor jack, with L4 (1 mH) | Battery terminals W5 to W9 |
| C9 | 470 µF | 16 V | 270109-5215 | Supply to the sound amplifier Q3, with R6 (1 kΩ) | Q3 |
The schematic and the parts list agree on all three values and ratings.[1][2]
Other capacitors
[edit | edit source]The remaining capacitors are ceramic and metallised polyester types; capacitors not listed separately are 10 %, 500 V parts unless the schematic says otherwise.[1]
- C4, a 6–38 pF trimmer, sets the 2 MHz oscillator. C3 and C5 beside it are 82 pF ceramics with different temperature coefficients (NPO and N1500 in the parts list); replace them only with the same types.[1][2]
- C8 and C10 (0.056 µF, 250 V metallised polyester) are on the player control inputs, IC1 pins 11 and 12.[1][2]
- The RF section uses NPO ceramics and the 3–15 pF trimmer C14, which with L1 sets channels 3 and 4. Leave both alone during a recap, or repeat the RF adjustment afterwards.[1][4]
Procedure
[edit | edit source]- Take out the cells and unplug the adaptor.
- Remove the bottom cabinet as described on the maintenance page.
- Note the polarity of each capacitor before removing it.
- Fit 470 µF capacitors rated 16 V or more.[1]
- Clean off flux, refit, and check 6.4 V at IC1 pin 4.[2]
- Check the picture on channels 3 and 4.[4]
Related pages
[edit | edit source]- Magnavox Odyssey 300
- Magnavox Odyssey 300 General Maintenance
- Magnavox Odyssey 300 Troubleshooting Guide
- Magnavox Odyssey 2000 Capacitor Replacement Guide
- Capacitor Failure Symptoms
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Magnavox, Service Manual No. 6504, October 1976, p. 6504-2: BG7500 replacement parts list (coils, capacitors with type, value, rating and part number, controls and switches, semiconductors, miscellaneous), antenna/game switch parts list and cabinet parts list. Hosted as File:Magnavox Odyssey 300 Service Manual 6504.pdf.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Magnavox, Service Manual No. 6504, October 1976, pp. 6504-3 and 6504-4: BG7500 schematic diagram, with the transistor voltages marked on it, the note on the early and late production regulator zener, and the IC1 voltage chart with its notes 1 to 8. Hosted as File:Magnavox Odyssey 300 Service Manual 6504.pdf.
- ↑ 3.0 3.1 Magnavox, Service Manual No. 6504, October 1976, pp. 6504-5 and 6504-6: main P.C. board viewed from the component side (board 211077-1) and a drawing of the console's controls. Hosted as File:Magnavox Odyssey 300 Service Manual 6504.pdf.
- ↑ 4.0 4.1 4.2 The Magnavox Company, Service Manual No. 6504: BG7500 Odyssey, first issue, October 1976, p. 6504-1: general information (6 C cells or an optional AC to DC 9 V adaptor; Hockey, Tennis and Smash; Novice, Intermediate and Expert skill levels; on-screen scoring, automatic serve, 15-point game; a different tone for each hit or point and no provision to turn the sound off), the service adjustments (2 MHz oscillator; channel 3 and 4 RF oscillator) and typical operation. Hosted as File:Magnavox Odyssey 300 Service Manual 6504.pdf.