Jump to content

Magnavox Odyssey 500 Capacitor Replacement Guide

From RetroTechCollection
Magnavox Odyssey 500 BG7520 board layout (SM 6506)
Component view of the BG7520 (Odyssey 500) board, with every capacitor position labelled (Magnavox Service Manual No. 6506, p. 6506-8)

The Magnavox Odyssey 500 (BG7520) has seventeen electrolytic capacitors on its single board. Magnavox's Service Manual No. 6506 lists each one's value, voltage rating and part number, the schematic shows its circuit, and the component-side drawing shows where it sits.[1][2][3] For failure signs in general see Capacitor Failure Symptoms.

Before replacing anything

[edit | edit source]

The console runs from a 9 V, 200 mA AC adaptor, so there are no mains voltages inside it.[4] Magnavox's documents name no capacitor as a known fault. Measure the current drain first: Magnavox gives 185 mA nominal and 200 mA maximum, and warns that excessive current will mean replacing IC1.[4][5] C1 and C7 sit across the 9 V and 5 V supply lines, so check them for a short before condemning IC1.[2]

Electrolytic capacitors

[edit | edit source]
Odyssey 500 (BG7520) electrolytic capacitors
Ref Value Rating Magnavox part no. Circuit (schematic) Beside (board drawing)
C1 470 µF 16 V 270109-5215 9 V supply after the power switch S1A, at the input of L1 (68 µH) to IC1 pin 2 Sound switch S4
C2 22 µF 25 V 270111-2125 IC1 pin 4 (lower rebound damping), with R7 (100 kΩ) Rebound controls R2 and R3
C3 22 µF 25 V 270111-2125 IC1 pin 8 (upper rebound damping), with R6 (100 kΩ) Rebound controls R2 and R3
C4 10 µF 25 V 270111-1125 IC1 pin 5, with R5 (22 kΩ) Rebound controls R2 and R3
C6 2.2 µF (see note) 50 V 270109-2050 IC1 pin 13, with the right wall control R13 Right wall control R13
C7 220 µF 16 V 270109-2215 Regulated 5 V line from IC1 pin 3 IC1, at the "+5V REG" marking
C14 47 µF 16 V 270111-5115 IC3 pin 3, with the SPEED control R19 SPEED control R19
C15 2.2 µF 50 V 270109-2050 IC3 pin 14, with the CENTER (left wall) control R22 CENTER control R22
C16 10 µF 25 V 270111-1125 IC3 pin 12, with the goal control R25 Goal control R25
C32 4.7 µF 50 V 270111-5050 IC2 pin 6 (lock-out time), through R46 (10 kΩ) IC6
C33 10 µF 25 V 270111-1125 IC8 pin 2 network, with R47 (33 kΩ) and diode D12 IC8
C34 47 µF 16 V 270111-5115 IC8 pin 2 IC8
C35 47 µF 16 V 270111-5115 IC8 pins 12 and 13, with R51 (47 kΩ) IC8
C57 2.2 µF 50 V 270109-2050 IC7 pin 4, left player vertical control R71 Left player vertical control R71
C58 2.2 µF 50 V 270109-2050 IC7 pin 2, left player horizontal control R74 Left player vertical control R71
C59 2.2 µF 50 V 270109-2050 IC7 pin 14, right player vertical control R77 Right player vertical control R77
C60 2.2 µF 50 V 270109-2050 IC7 pin 16, right player horizontal control R80 Right player horizontal control R80

[1][2][3]

The parts list prints C6 as "22 mfd., 50V", but gives it part number 270109-2050, the number it uses for the 2.2 µF, 50 V capacitors C15 and C57 to C60, and the schematic marks C6 as 2.2 µF. Read the value on the part fitted before ordering.[1][2]

Other capacitors

[edit | edit source]

The remaining capacitors are polyester film and ceramic types. Capacitors not listed separately are 10 %, 500 V parts unless the schematic says otherwise.[1]

  • C41, the 3.58 MHz oscillator trimmer beside crystal X1, sets the colours. The parts list gives it as 3–15 pF (260220-4) and the schematic as 4–20 pF. Leave it alone during a recap; Magnavox says to adjust it only when essential.[1][2][5]
  • The RF section around Q4 uses NPO ceramic capacitors (C80, C81) and a 3–15 pF trimmer, C76. Magnavox forbids any RF adjustment.[1][5]

Procedure

[edit | edit source]
  1. Unplug the adaptor.
  2. Remove the cabinet bottom as described on the maintenance page.
  3. Photograph the board and note the polarity of each capacitor before removing anything.
  4. Fit capacitors of the same value and at least the same voltage rating as the parts list gives.[1]
  5. Check the board for shorts and solder bridges, then power it with the current drain monitored: about 185 mA, and no more than 200 mA.[5][4]
  6. Check 4.5 V to 5.5 V at IC1 pin 3, then the picture, and repeat the rebound, blanking, wall, goal and score adjustments if needed.[4][5]
[edit | edit source]

References

[edit | edit source]
  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Magnavox, Service Manual No. 6506, December 1976, p. 6506-9: replacement parts list (coils, capacitors with type, value, rating and part number, controls and switches, semiconductors, AC adaptor and miscellaneous) and the antenna/game switch parts list. Hosted as File:Magnavox Odyssey 500 Service Manual 6506.pdf.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Magnavox, Service Manual No. 6506, December 1976, pp. 6506-5 and 6506-6: BG7520 schematic diagram, with the power switch, adaptor jack J1, IC1 to IC8, crystal X1, the RF section and the antenna switch box. Hosted as File:Magnavox Odyssey 500 Service Manual 6506.pdf.
  3. ↑ 3.0 3.1 Magnavox, Service Manual No. 6506, December 1976, p. 6506-8: BG7520 main P.C. board (component view), board 703839. Hosted as File:Magnavox Odyssey 500 Service Manual 6506.pdf.
  4. ↑ 4.0 4.1 4.2 4.3 The Magnavox Company, Service Manual No. 6506: BG7520 Odyssey, first issue, December 1976, p. 6506-1: general information (9 V 200 mA AC adaptor; Hockey, Tennis, Smash and Soccer; three styles of players; colour background and players, automatic serve, digital on-screen scoring) and the specifications table. Hosted as File:Magnavox Odyssey 500 Service Manual 6506.pdf.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 Magnavox, Service Manual No. 6506, December 1976, p. 6506-3: service adjustments (the warning on current drain and IC1, score indicator position, rebound, blanking with Figure 1, the instruction not to adjust the RF section, video level, 3.58 MHz oscillator, background colour, player size balance, right wall, goal opening) and the IC basic functions. Hosted as File:Magnavox Odyssey 500 Service Manual 6506.pdf.


Retrieved from "https://retrotechwiki.com/index.php?title=Magnavox_Odyssey_500_Capacitor_Replacement_Guide&oldid=27282"