VOGONS


First post, by Machine_1760

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I've just acquired an old mac, problem is that I only have 'normal' monitors and the mac has a two layer low density connector for video. I know the pin outs to build an adaptor to solve this problem but i'm having trouble understanding the sense modes. from what i can gather the computer will detect the monitor type and set resolution and refresh rates accordingly. The listed monitor types do not correspond to standard configurations.

Could anyone here tell me what I need to do?

Reply 1 of 3, by Machine_1760

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Wow! 68 views and no-one knows anything?!?

Well, in case anyone cares or needs to know also:
The sense pins these days do not really serve much of a purpose. As long as the monitor can support various refresh rates its just a matter of connecting pins 7 and 10 with a diode orientated so that the signal has to go from 10 to 7. This will allow resolution and refresh rate changes up to 1152x870.

If your monitor can only support 1024x768 (15'' or lower) then simply reverse the diode.

I've attached pics of the finished adapter and pin outs can be easily found online.

Reply 2 of 3, by Anonymous Freak

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Sorry, I had missed your original post! Had I noticed it, I would have answered for you; and even offered to send you an adapter. 😜 (I have a couple dozen of the little buggers.)

There are a couple types out there.

One is a "fixed frequency" that identifies your VGA-connected monitor as supporting only one specific resolution/refresh rate. These are generally very old.
The second is "jumpered", where you set a bunch of jumpers on the adapter to force the adapter to identify itself to the Mac as one specific monitor. Some jumper settings force a specific resolution/refresh rate, others allow multi-scan mode with a certain max-allowed resolution/refresh rate.
Third are the auto-sensing, which just translate the VGA-standard DDC signal into Apple's equivalent, so it generally allows the full capability of your multiscan display.

Reply 3 of 3, by Machine_1760

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Thanks, Good stuff to know.

So it sounds like I've made a jumpered adapter effectively with a fixed jumper - in this case a diode. I was working from common sense and a pretty vague pin out list!

I don't suppose you have the pinouts of the auto-sensing adapter? It sounds like that's the one i need!