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Macintosh 12 RGB Display Service Source

From RetroTechCollection

The Macintosh 12" RGB Display volume of Apple's Service Source is a 113-page service manual for Apple's 12-inch colour display. The PDF's creation date is 13 December 1995.[1]

Specifications

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Macintosh 12" RGB Display specifications[2]
Item Value
Picture tube 12 in viewable diagonal; 90° deflection; black-matrix dot screen; P22 phosphor (aluminised); spherical, antiglare
Resolution 512 × 384, 64 dpi; up to 256 colours with the Macintosh Display Card 4•8 and 16.7 million with the 8•24
Scan rates Vertical 60.15 Hz; horizontal 24.48 kHz; rise and fall time 27 ns maximum
Active display area 8.08 × 6.02 in (205 × 153 mm)
Input signals Analogue red, green and blue, RS-343
Power supply International: universal, 90-270 V AC self-configuring, 47-63 Hz, 90 W maximum. Domestic: 100-120 V AC, 50-60 Hz, 90 W maximum
Size and weight 12.2 in (310 mm) high, 14.4 in (365 mm) wide, 10.0 in (253 mm) deep; 35 lb (15.9 kg)
Operating environment 10-40 °C; 95% RH maximum, non-condensing; up to 10,000 ft, with the 40 °C limit derated above 7,000 ft

Contents

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  • Specifications (PDF pp. 3-7)
  • Troubleshooting (PDF pp. 9-18): symptom charts for no raster, geometry, synchronisation, video and miscellaneous faults
  • Take Apart (PDF pp. 20-65): rear cover, contrast/brightness assembly, fuse, CRT/video board, external power cable, CPU-to-monitor cable, main deflection board and holder, CRT assembly, LED assembly cable, bezel
  • Adjustments (PDF pp. 67-111): screen voltage, geometry, video (white balance and screen luminance), light meter set-up
  • Exploded View (PDF pp. 112-113)

What it settles

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There are two revisions of the main deflection board, and they are not interchangeable. A Rev. B board has a grey coil, VR504, next to connector J502; a Rev. A board does not. The CRT must match: Rev. A boards take the standard CRT 076-0384 and Rev. B boards the low-ELF CRT 076-0395, which has two field coils, one above and one below the tube.[3]

The fuse is F901 on the main deflection board.[4] The exploded view lists it as part 941-5222 with no rating, and gives the other part numbers: main deflection board 661-0616 (Rev. A) or 661-0659 (Rev. B), CRT/video board 661-0618 or 661-1618 (Rev. B), contrast/brightness assembly 905-0009, LED assembly and cable 930-0008, bezel 949-0297, rear cover 949-0298, power cable 936-0107 and CPU-to-monitor cable 590-0693.[5]

The screen voltage adjustment is needed only after replacing the main deflection board or a CRT/yoke assembly of a different revision, or if the screen control has been moved. It uses Apple's high-voltage probe 076-0392 (40 kV rating, 1000 MΩ input impedance) with the meter on its 2 V DC range, at the SCREEN test point (US version) or PIN 4 (international version). The target is 500 V for CRT type AT12A9SL and 400 V for type M29JMN097X13, read from the label on the side of the tube. Sub-brightness and sub-contrast are then reset; screen luminance is 30 foot-lamberts (±3).[6]

The geometry controls are V-CENT (VR403), H-CENT (VR503), H-PHASE (VR501), H-WIDTH (L501, set with a hex-head insulated tool to 205 mm ±2 mm), V-HOLD (VR401), H-HOLD (VR502), V-LIN and FOCUS; SUB-BRIGHT is VR202. The Take Apart procedures begin with discharging the CRT and removing the anode cap, and warn never to wear a grounding wrist strap until the CRT has been discharged. See CRT Discharge Procedure.[7]

What this manual does not contain

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There is no schematic, no component values and no fuse rating. There is no low-voltage supply adjustment or rail tolerance; the only voltage adjustment is the CRT screen voltage.[1]

Pages that cite this document

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Download: 12 rgb display.pdf

References

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  1. ↑ 1.0 1.1 Apple Computer, Inc., Macintosh 12" RGB Display (Service Source), 113 pp. Hosted as File:12 rgb display.pdf.
  2. ↑ Macintosh 12" RGB Display Service Source, Specifications, pp. 1-5 (PDF pp. 3-7).
  3. ↑ Macintosh 12" RGB Display Service Source, Take Apart, Main Deflection Board, pp. 32-33, and CRT Assembly, pp. 41-42 (PDF pp. 51-52, 60-61).
  4. ↑ Macintosh 12" RGB Display Service Source, Take Apart, Fuse, pp. 8-9 (PDF pp. 27-28).
  5. ↑ Macintosh 12" RGB Display Service Source, Exploded View (PDF p. 113).
  6. ↑ Macintosh 12" RGB Display Service Source, Adjustments, Screen Voltage, pp. 3-15, and Video, pp. 38-39 (PDF pp. 69-81, 104-105).
  7. ↑ Macintosh 12" RGB Display Service Source, Adjustments, Geometry, pp. 16-28, and Take Apart, pp. 5-6 (PDF pp. 82-94, 24-25).
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