Apple 16" Color Display Troubleshooting Guide
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Fault-finding for the Macintosh 16" Color Display, from Apple's Service Source symptom charts.[1] Apple lists cures in order of likelihood; refit the original module before moving on if a replacement made no difference. Rule out the environment first: distortion and jitter from nearby metal, lights and appliances cannot be cured by swapping modules.[2]
Discharge the CRT before working inside (see CRT Discharge Procedure) and do not wear a grounding wrist strap until it has been discharged.[3]
No raster
[edit | edit source]| Symptom | Cures, in Apple's order |
|---|---|
| No raster, LED off | Check the power cord and power switch. Check all main board cable connections. Replace a blown fuse. Replace the main board |
| No raster, LED on, CRT heater glowing | Adjust contrast and brightness. Check the video card. Check the connectors on the main board and CRT/video board. Do the video adjustments. Replace the main board. Replace the CRT/video board. Replace the CRT |
| No raster, LED on, heater not glowing, high voltage present | Check the connection at D-5 on the main board. Check continuity of the D-5 cable from the heater (H) pins on the CRT socket; if it is open, replace the CRT/video board. Replace the main board |
The fuse is on the main board. With the stand and cover removed and the CRT discharged, disconnect the AC inlet cable if it is in the way and lever one end of the fuse up with a small long-shafted screwdriver.[4] Apple gives it as part 922-0516 with no rating.[5]
Geometry and synchronisation
[edit | edit source]| Symptom | Cures, in Apple's order |
|---|---|
| Raster too short, tall, narrow or wide | Adjust the vertical or horizontal size controls. Replace the main board |
| Raster not centred | Move the display to rule out the environment. Adjust horizontal shift or vertical centre. Replace the main board |
| Horizontal linearity bad (text size differs at the sides) | Replace the main board |
| Vertical linearity bad (text size differs top and bottom) | Adjust vertical linearity. Replace the main board |
| Abnormal or distorted raster | Move the display away from other monitors and electrical equipment. Do the geometry adjustments. Replace the main board. Replace the CRT |
| Whole raster tilted | Move the display away from other monitors and electrical equipment |
| Picture breaks into diagonal lines | Connect another monitor to check the video signal. Replace the main board |
| Picture rolls vertically, or breaks and rolls horizontally | Check the video card. Replace the main board |
| Single vertical or horizontal line on a black raster | Check the CRT/video board is pushed fully onto the CRT neck and yoke connector. Replace the main board. Replace the CRT |
Video
[edit | edit source]| Symptom | Cures, in Apple's order |
|---|---|
| Colour tint, or colour cannot be adjusted | Check the video card. Check switch SW1 on the underside of the CRT/video board is set towards the neck of the CRT. Do the video adjustments. Replace the CRT/video board. Replace the CRT if a red, green or blue tint cannot be removed |
| Picture too dark, too bright or washed out | Adjust contrast and brightness. Check the video card. Do the video adjustments. Replace the CRT/video board, then the main board, then the CRT |
| Out of convergence (colour fringes on text and lines) | Do the convergence adjustment. Replace the CRT |
| Green vertical line at the left of the screen | Check SW1 as above. Do the video adjustments. Replace the CRT/video board. Replace the CRT |
| Out of focus | Do the focus adjustment. Replace the CRT. Replace the main board. Replace the focus control |
Miscellaneous
[edit | edit source]| Symptom | Cures, in Apple's order |
|---|---|
| Shuts down intermittently | Replace the main board |
| Picture jitters or flashes | Check the ground cables. Check nearby equipment is grounded. Move electrical devices away and switch off nearby fluorescent lights. Replace the main board |
| Flashing or wavy screen | Replace the main board |
| Black spots (burnt phosphor) | Replace the CRT |
| Does not degauss | Replace the main board |
| ADB devices do not work or work erratically | Replace the keyboard cable, keyboard, mouse or other ADB device. Replace the ADB cable in the monitor stand |
| High-pitched noise | Replace the main board |
| Thin horizontal lines across the screen | Not a fault: the two support wires of the Trinitron aperture grille, a quarter to a third of the way from the top and bottom. They cannot be adjusted out or removed by replacing modules |
The video, focus and convergence adjustments are on the general maintenance page.
Main board revisions
[edit | edit source]Replace the main board like for like. If vendor part number A-1335-028 appears near connector D3, order 661-1634; otherwise the board is Rev. B, 661-1671.[6] Apple's 1996 service guide shows both revisions in its main board drawing.[7]
Related pages
[edit | edit source]- Apple 16" Color Display
- Apple 16" Color Display General Maintenance
- Macintosh 16 Color Display Service Source
- CRT Discharge Procedure
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 Apple Computer, Macintosh 16" Color Display (Service Source), hosted as File:16 color display.pdf. Troubleshooting: general p. 1, symptom charts pp. 2-10 (PDF pp. 18-27).
- ↑ Macintosh 16" Color Display Service Source, Basics, Monitor Distortion, pp. 1-7 (PDF pp. 3-9).
- ↑ Macintosh 16" Color Display Service Source, Take Apart, pp. 1-57 (PDF pp. 29-85).
- ↑ Macintosh 16" Color Display Service Source, Take Apart, Fuse, pp. 56-57 (PDF pp. 84-85).
- ↑ Macintosh 16" Color Display Service Source, Exploded View (PDF p. 136).
- ↑ Macintosh 16" Color Display Service Source, Take Apart, Main Board, p. 40 (PDF p. 68).
- ↑ Apple Computer, Macintosh Displays and Video Cards service guide, September 1996, hosted as File:Apple Macintosh Displays and Video Cards Service Guide (September 1996).pdf. Chapter 15, main circuit boards p. 213 and parts list p. 214 (PDF pp. 231-232).