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How to use mac to vga adapter?

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Niezgodka

Experienced Member
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Oct 13, 2017
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I have two of these. The one on left works, and has no switches. The one on right does not produce any signal. I imagine it is requiring some setup, but I have no idea what to turn on and off on it.
Does anybody has adapter like this and can share with switch set up?
mac-adapter.jpg
 
The switches are set to generate the monitor sense codes shown on the left
they are probably underneath a cover. Why would they print a switch settings
label if there are no switches?

Not all video cards or models of Mac support the modes shown, in particular
no Macs in the 80s supported IBM 640 x 480 VGA horizontal/vertical sync timings.

the basics of how these adapters work is http://www.codesrc.com/mediawiki/ind...=Macintosh_VGA and the notes it points to

I don't know if anyone has documented all of the variations in switches from all of the different people that made the things

annoyingly, the source documents are vanishing from the web
https://wiki.preterhuman.net/Macinto...or_Sense_Codes
http://mirror.informatimago.com/next...rMacG3.46.html

you'd think by now someone would have drawn a schematic of the things, but I can't find it, I may just have to rip one of
mine apart and do it
 
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Here's a listing on Amazon for what looks like your particular adapter:

https://www.amazon.com/Adapter-DB15-Male-Female-Switches/dp/B0016OC1J2

There's a guy who posted a hard-to-read image of the piece of toilet paper included with the device that has the switch settings on it. Googling some phrases on that lead me to this, which unfortunately isn't a lot clearer.

Knowing what kind of Mac you're trying to hook up to and what you're using for a monitor would help a lot in guessing what switch settings were apropos. If it's a Macintosh LC III or newer "2367" would probably work with most generic LCD monitors, assuming that's the right piece of toilet paper for your adapter.
 
I was hoping to use it with my Macintosh Performa 636 with standard SVGA CRT monitor.

Actually, upon closer inspection, I noticed that adapter on left has switches as well, but they are hidden and there are 8 of them.
Should I try set first 8 the same way on the other one?

IMG-9964.jpg
 
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14678 works the way it should be! I have no idea how did you figure it out from that "helpful" instruction. Thank You so much!
 
You’re welcome. If you ever need to use this adapter on an older Mac (you are lucky with a Performa 630/Quadra era machine because they have Extended Sense Line support and thus you can use the multisync settings, you’re not stuck trying to emulate an older fixed frequency monitor) here’s the biggest hint I can give you: most modern monitors will want separate sync, so use the settings in the column for “Mode 5”.
 
You don't need to emulate anything with Mac II video. If your mac can output 640x480@67 Hz, then you're fine because a good number of LCD monitors both old and new support that resolution. If you don't have one, just pick up an old 15" square Dell monitor, it supports lots of weird resolutions and refresh rates because they still had DOS support in mind.

Only the oddball resolutions like 512x384, 832x624 and 1152x870 are problematic. Most LCD monitors won't sync to 512x384 because it's too low of a resolution, and the other two were never standard either. 3rd party video cards for the Macintosh did often support the more standard modes like 800x600 and 1024x768, and those generally work fine with LCD monitors.
 
GiGaBiTe said:
You don't need to emulate anything with Mac II video. If your mac can output 640x480@67 Hz, then you're fine because a good number of LCD monitors both old and new support that resolution. If you don't have one, just pick up an old 15" square Dell monitor, it supports lots of weird resolutions and refresh rates because they still had DOS support in mind.
Click to expand...

I was using the word "emulate" loosely; basically to mean that if you have one of those older Mac video systems that don't support Multisync you will probably be forcing your monitor to accept a mode/resolution which doesn't have an exact "PC standard" equivalent, which adds a little bit of uncertainty whether things are going to work. You're right, most older 4:3 monitors do okay, but some newer LCDs are really anal about not liking non-VESA refresh rates, of which 67hz is an example of.

So far as it goes most 1280x1024 monitors I've tried (it has been a long time, though) can manage to at least display the 832x824 and and 1152x870 pixel modes, but the latter in particular usually doesn't look so great. But, yes, the 12" 584x384 mode won't fly on almost anything made after the early 1990's, that's not even an LCD-specific limitation.
 
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