Apple High Resolution Monochrome Monitor Troubleshooting Guide
Fault-finding on the Apple High-Resolution Monochrome Monitor from Apple's Service Source symptom charts. Apple lists cures in order of likelihood: try the first, check whether the symptom remains, and if a module swap does not cure it, refit the original module before trying the next cure.[1]
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Read CRT Discharge Procedure before opening the monitor, and Apple High Resolution Monochrome Monitor General Maintenance for the take-apart and adjustments.
Symptom charts
edit| Symptom | Cures, in order |
|---|---|
| No raster, LED off | Check the video cable to the computer or video card; check the power cord; check the internal power connectors; replace the fuse; the power supply; the power switch |
| No raster, LED on | Check the video cable; adjust brightness and contrast; replace the computer's video card if fitted; adjust sub-brightness (cutoff); check the logic board connection to the power supply; replace the fuse; the main board; the power supply; the power switch assembly; video board C; the contrast control board |
| Raster stretched or compressed at a side or the top | Check whether the distortion comes from the surroundings; do the geometry adjustments; replace the main board; the CRT |
| Picture breaks into diagonal lines | Check the computer's video signal on another monitor; replace the main board |
| Picture rolls vertically | Check the computer's video card; adjust vertical hold; check the connector on the I/O connector board; replace the main board |
| One horizontal or vertical line | Check the yoke connectors; replace the main board; the CRT |
| Picture too dark or too bright | Adjust the brightness knob; check the video card; adjust sub-brightness (cutoff); replace the main board; video board C; the CRT |
| Brightness will not adjust | Replace the contrast control board; the main board; video board C; the CRT |
| Out of focus | Do the focus adjustment; replace the main board; video board C; the CRT |
| Picture jitters | Check the grounding cable connections to the chassis; check that nearby computer equipment is properly grounded, move electrical devices away and turn off fluorescent lights for a test; replace the main board |
| Flashing lines on the screen | Check the contact of the video connector on the CRT neck; replace the contrast control board; the main board |
| Black spots (burnt phosphor) | Replace the CRT |
Notes
edit- The monitor runs at one fixed timing: 640 × 480, 35.0 kHz horizontal, 66.7 Hz vertical.[2] Apple's charts check the card before the monitor.[1]
- Shut-down while setting the cutoff control is the monitor's protection. Turn cutoff fully anticlockwise, wait 30 seconds and start again.[3]
- Video board C is mounted on the tube neck; twisting it while removing it can crack the neck.[4]
- If the Service Source charts do not settle it, Apple refers to its flowchart for the product family and to Apple Technical Support.[1] The 1987 Technical Procedures have their own symptom chart.[5]
Related pages
editReferences
edit- ↑ 1.0 1.1 1.2 Apple Computer, Apple High-Resolution Monochrome Monitor (Service Source), Troubleshooting, General and Symptom Charts, pp. 1-6 (PDF pp. 9-14). Hosted here: File:Highres monochrome monitor.pdf (see Apple High-Res Service Source).
- ↑ Apple High-Resolution Monochrome Monitor Service Source, Specifications, Characteristics, pp. 1-2 (PDF pp. 3-4).
- ↑ Apple High-Resolution Monochrome Monitor Service Source, Adjustments, Video, p. 12 (PDF p. 62).
- ↑ Apple High-Resolution Monochrome Monitor Service Source, Take Apart, Video Board C, p. 23 (PDF p. 38).
- ↑ Apple Computer, High-Res Monochrome Monitor Technical Procedures, 1987, Section 4, Troubleshooting. Hosted here: File:Apple High-Res Monochrome Monitor Technical Procedures.pdf.