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Apple Monochrome Monitor Troubleshooting Guide

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Apple Monochrome Monitor (Apple owner's guide cover, 1986)

Fault-finding on the Apple Monochrome Monitor (A2M6016). Apple serviced it at module level, so its symptom chart names the module to change, not the component. Apple's instruction is to try the actions in order and to put the original module back if an action does not cure the fault.[1] Apple's service documents for it include no schematic, so board-level work means tracing the circuit on the board.

Read CRT Discharge Procedure before opening the case, and Apple Monochrome Monitor General Maintenance for the take-apart.

Checks before opening

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  • The monitor takes composite video on the RCA jack at 15.7 kHz and 59.9 Hz. It shows 640 × 200 from an Apple IIGS and 560 × 192 from a IIc or IIc Plus.[2] Connect it to the computer's composite video (phono) output.
  • The external brightness control is on the back, the contrast control on the side under the power switch.[3] Turning both down gives a blank screen that looks like a fault.
  • Rolling or tearing pictures can be the rear vertical or horizontal hold controls.[4]

Apple's symptom chart

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Monochrome Monitor symptom chart (Technical Procedures pp. 4.2-4.3)
Symptom Actions, in order
No power (LED does not light) Check the fuse and replace if blown; if it blows again, replace the transformer. Replace the transformer. Replace the power switch
No raster Check the video cable. Adjust the external brightness control. Adjust the contrast control. Check all connectors on the CRT board and main logic board. Replace the main logic board. Replace the CRT
One vertical line Replace the main logic board; replace the CRT assembly
Raster deformed Replace the CRT assembly
Wavy picture Replace the main logic board
Spot remains after switch-off Replace the main logic board
Brightness range abnormal Replace the main logic board; replace the power transformer
Small raster, picture abnormally bright Replace the main logic board
No vertical sync Replace the main logic board
Screen bright, no picture Replace the main logic board
15 seconds or more for the picture to appear Replace the CRT assembly
Picture appears and disappears Replace the main logic board; replace the CRT assembly
Out of focus Adjust focus (Adjustments)
Will not focus Replace the main logic board; replace the CRT
Narrow raster Replace the main logic board
Picture compressed or stretched Replace the main logic board
Picture tears Adjust horizontal hold (Adjustments)
Image reversed left to right after service Yoke connector P4 is plugged in backwards
Image upside down after service Yoke connector P3 is plugged in backwards

Notes on the chart

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  • Focus that the focus control will not improve is also a CRT replacement in Apple's adjustment procedure.[5]
  • Apple says not to touch the yoke, and its cure for a deformed raster is a new CRT assembly.[3]
  • Main logic boards for 110 V (661-0346) and 220/240 V (661-0362) are different parts, as are the three transformers (915-0009, -0010, -0011). Check the voltage before swapping a board or transformer from another monitor.[6]
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References

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  1. ↑ Apple Computer, Monochrome Monitor Technical Procedures, in Apple Service Technical Procedures: Apple II Family, Volume Two, 072-0229, November 1991 build, Troubleshooting, pp. 4.2-4.3 (PDF pp. 42-43). Hosted here: File:Apple Monochrome Monitor Technical Procedures.pdf.
  2. ↑ Apple Computer, Apple II Monochrome Monitors data sheet, September 1988, A2F2221/A. Hosted here: File:Apple II Monochrome Monitors Data Sheet 1988.pdf.
  3. ↑ 3.0 3.1 Monochrome Monitor Technical Procedures, Adjustments, Introduction, p. 3.3 (PDF p. 33).
  4. ↑ Monochrome Monitor Technical Procedures, Basics, p. 1.2 (PDF p. 6).
  5. ↑ Monochrome Monitor Technical Procedures, Adjustments, Focus, p. 3.9 (PDF p. 39).
  6. ↑ Monochrome Monitor Technical Procedures, Illustrated Parts List, p. 5.5 (PDF p. 49).


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