RetroTechCollection

Apple AppleVision 850 Display Capacitor Replacement Guide

Electrolytic capacitors on the main deflection board of the AppleVision 850 and 850AV. Both models use the same main deflection board, Apple part 661-1213.[1] Apple published no component list for it: its Service Source treats the board as a module and gives no schematic or component values.[2]

Main deflection board of an AppleVision 850AV with the electrolytic capacitors marked: CP (green), CL (blue) and CF (orange) (photo: Elemenoh, TinkerDifferent)

The list below was compiled by a TinkerDifferent forum member, Elemenoh, from an 850AV board in 2022, with a photograph marking each position. It is a single owner's survey of one board, not an Apple parts list; check each position on your own board before ordering.[3]

Safety

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The main deflection board carries the power supply and the flyback circuit. The CRT anode runs at 27 kV.[4] Unplug the display, discharge the CRT, remove the anode cap and fit an ongoing ground lead from the anode aperture to the CRT ground strap before removing the board, as Apple's take-apart procedure requires.[5] See CRT Discharge Procedure. CP11 is a 100 µF, 400 V part and can hold a dangerous charge after the display is unplugged; discharge it before handling the board.

Main deflection board capacitor list

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AppleVision 850AV main deflection board electrolytic capacitors (community list)[3]
Position Capacitance (µF) Voltage (V) Size, diameter × height (mm) Temperature rating (°C)
CP9 68 25 6.5 × 11 105
CP10 1 50 5 × 11 105
CP11 100 400 22.3 × 30.3 105
CP12 47 250 16 × 31.5 105
CP13 270 100 13 × 42 105
CP14 470 16 8 × 20 105
CP15 1,000 16 10.25 × 30 105
CP16 1,000 16 10.25 × 30 105
CP17 1,500 16 13 × 25.5 105
CP25 470 10 8.2 × 15 105
CP28 100 25 6.5 × 15 105
CP29 22 35 5 × 12 105
CP40 22 50 6.5 × 12 105
CP41 1 50 5 × 12 105
CP42 2,200 35 16.2 × 37.2 105
CP44 820 25 10.3 × 31 105
CP51 1 50 5 × 12 105
CP67 22 35 5.3 × 11.5 105
CP68 47 16 5.3 × 11.5 85
CP69 47 16 5.3 × 11.5 85
CL2 22 250 13.2 × 26 105
CL6 470 10 8 × 15 105
CL21 47 100 10 × 21 105
CL27 22 250 13.2 × 26 105
CL37 100 25 6.5 × 10 85
CL38 470 16 8.3 × 20 105
CL43 100 16 6 × 12 85
CL58 100 16 6 × 12 85
CL61 1 50 5 × 10 85
CL62 10 50 5 × 11 85
CL84 100 16 6 × 12 85
CL87 2.2 200 6.5 × 12 85
CF1 220 35 10.5 × 13 85
CF2 220 16 8 × 12 85
CF4 1,000 16 10.3 × 20 85

The list has 35 capacitors: 20 in the CP series, 12 CL and 3 CF. The photograph also marks a CL72 that is not in the list, and does not mark CL27 or CL62; check those three positions on the board.[3]

What the list does not cover

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  • The CRT/video (neck) board. The same owner later replaced "all 100 µF caps" on it without listing them.[3]
  • The 850AV's sound board (922-2650) and power board (922-2652) in the sound enclosure.[1]
  • The 850's ADB board.

Owner's findings

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The owner measured the capacitors he suspected first (the secondary side of the power supply and the deflection circuits). Most were within a few per cent of their marked value; CP14 read 16% low, CP15 and CP16 12% low and CL6 11% low, and CL43, a bypass capacitor on the emitter of transistor QL20 in the horizontal circuit, read 22% low. He replaced CP14, CP15, CP16, CP25, CL6 and CL43. These replacements did not cure that display's fault, a narrow, distorted picture at all but one resolution, which is covered on the troubleshooting guide.[3]

Procedure

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  1. Remove the housings and the main deflection board following Apple's take-apart chapter, with the CRT discharged and the ongoing ground lead fitted.[2]
  2. Photograph the board and note the polarity of every capacitor before removing any.
  3. Replace one capacitor at a time with a part of the same capacitance and at least the same voltage rating, checking that taller replacements clear the heatsinks and the chassis.
  4. Refit the board, reconnect the yoke wires to BF1 and BL1 clear of the ribbon cables (Apple gives bundling them as a cause of corrupted set-up data and a frozen screen), and check the high voltage reads 27 kV.[4][6]

See Capacitor Failure Symptoms for signs of failed capacitors.

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References

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  1. ↑ 1.0 1.1 Apple Computer, 20" ColorSync Displays (Service Source), hosted as File:Colorsync 20 displays.pdf. Exploded View (PDF p. 177).
  2. ↑ 2.0 2.1 20" ColorSync Displays Service Source, Take Apart and Exploded View (PDF pp. 64-177).
  3. ↑ 3.0 3.1 3.2 3.3 3.4 AppleVision 850AV Repair, TinkerDifferent forum (Elemenoh), 2022-11-06—link(accessed 2026-10-02) Community source: capacitor list and capacitor map of the main deflection board (the post was corrected to give CP42 as 2,200 µF).
  4. ↑ 4.0 4.1 20" ColorSync Displays Service Source, Troubleshooting, Checking High Voltage, pp. 18-19 (PDF pp. 59-60).
  5. ↑ 20" ColorSync Displays Service Source, Take Apart, Safety Guidelines, pp. 1-2 (PDF pp. 65-66).
  6. ↑ 20" ColorSync Displays Service Source, Troubleshooting, Symptom Charts: Miscellaneous, pp. 8-9 (PDF pp. 49-50).


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