2

I would like to take a compact Mac such like Macintosh SE, completely neglect the computing part of it, but be able to feed the CRT tube with an external video feed through Analog RCA cables. (Yellow connector) Black and white for me is fine and no sound is fine. I just want these old screens to play my video, no matter if the resolution is 640x480. Can it easily be done by feeding the 'vidout' pin on the motherboard? Thanks for any help. (I have no electronics skills, so your guidance will be appreciated!)

  • I don't think it's as simple as rewiring because you'd need to decode your input to provide the multiple outputs the motherboard normally provides to the analog board and monitor. – Brian H Jul 3 at 18:04
6

No. The Mac SE vertical and horizontal scan frequencies (designed into both the CRT yoke and the analog sweep generator circuits) are different from NTSC (and PAL) composite timing. And the Mac SE analog board requires separate vertical and horizontal sync inputs, not just a video signal. The analog board sync inputs need to be at TTL voltage levels, which is also different from composite video.

| improve this answer | |
6

No, for many reasons.

  • The yellow connector that you are talking about is called composite video. It's called "composite" because it combines several signals: vertical synchronization, horizontal synchronization, blanking, luminance (the black-white part), and chrominance (the color part). No model of Macintosh bothered to combine these signals, only to immediately uncombine them; instead, the signals directly went to the high-voltage CRT driver circuitry. So the Mac has no circuitry to decode composite video.
  • The compact Macs were monochrome, so the chrominance of a composite signal would be meaningless.
  • All of the compact Macs had 342 lines that were progressively scanned. It is incompatible with the North American NTSC video format, which had 483 visible scan lines in an interlaced format. It is also incompatible with the European PAL video format, which has 576 visible scan lines, either interlaced or progressive. Either way, the Mac monitor does not have the correct number of lines for either video format.

I suppose someone who designs video circuitry for a living could salvage the CRT from the Mac and build some circuitry to drive the CRT using composite signals. But this is not at all a project for an amateur, and you would be better off using a CRT designed for composite video instead.

In addition, do NOT open the case of a compact Macintosh, as it has high voltages that can kill you if you do not know what you are doing.


One option that a few people have done is to take out all of the insides of a compact Mac, and replace them with a modern computer, as is shown here. If you are going to do that, please use a dead Macintosh. The thought of a perfectly good Mac being gutted this way makes me cry.

| improve this answer | |
  • 4
    In addition, do NOT open the case of a compact Macintosh, as this requires tools you probably don't have and you can kill the case if you do not know what you are doing. – Brian H Jul 3 at 18:38
  • 1
    You can kill the case opener if you don’t know what you are doing, especially if the case opener has health issues. By the way, Mac SE’s are monochrome. – Harper - Reinstate Monica Jul 5 at 3:03

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.