Changing screen size/resolution in "Settings"


Hello, I have a 17" monitor (KDS Avitron AV7-TF -- Sony Trinitron tube)), capable of displaying (at max)1280x1024@60Hz, 1152*870@75Hz, and 1024*768@85 Hz. BUT, I can't use 1152*870!!! AAAAARGH.

My card (the Blue & White G3 16 MB ATI RAGE 128) is quite capable of displaying all those sizes and refresh rates.

The problem I'm running into is that I CANNOT select 1152*870 @ 75Hz in OSX, my every-day working resolution. 60 Hz refresh rates flicker like crazy and drives my eyes nuts so I can't use 1280*1024, and 1024*768 is simply too small -- with OSX over-graphiced and large fonted (CAN FONT SMOOTHING BE TURNED OFF??? it's making text quite difficult to read) interface it leaves my 17" monitor feeling like a large 14" at 640*480!

What is happening (I think) is that with the OS 9.1 update/Mac OSX final Apple now uses Plug-and-Pray information from my monitor which lists only 640*480, 800*600, 832*624, 1024*768 & 1280*1024 as "recommended" screen sizes.

The Mac OS X public beta provided full support for my monitor and allowed me to manually configure what resolutions I wanted to support (awesome). This new mickey-mouse kiddy stuff is a pain in my derière.

Is there any software out there yet which will over-ride the @!#$)(*& settings "control panel" and allow me to use my screen sizes? Is it possible to take the software from the OSX public beta and replace the Displays setting in OSX final?

I'm not running OS 9.1 partly because it doesn't support my monitor properly (& SwitchRes & Super Res are unstable... the only non-Apple extension/control panel I run is Kensington Mousworks)... well, ok, the fact that OS 9.1 caused my machine to go into a never ending restart loop might also be playing a role in me staying with OS 9.04 ;).

Ah, Apple, brilliant sometimes, moronic at others. Why did you release a beta OS X as a "final" product. There is little of Apple's GUI magic in this release. I really hope they fix the inteface before the *next* "final" release!!!
In my Display panel, there's an option to Yes/No Display Recommended Resolutions. If you have that and select No, maybe you can select other resolutions.

I already tried selecting the "Display recommended resolutions" without success. All it does is activate the 640*480 screen size and maybe allow me to select one or two more refresh rates!

I need a way to replace the Displays setting control panel somehow.
I wonder if there's a preferences file somewhere that has resolution, and I wonder if you could manually edit it, and I wonder if you could then restart the WindowServer, and I wonder if I should shut up because I'd be asking you to fry your computer. In any event, there might be an awkward solution along those lines.

Hmm...If you like programming, there must be a hook into setting resolutions using the Core or Application Framework. I wouldn't know anything about it, but you might have an answer there too.

Hmm, sort of like that God-awful XF86Config file... I should look around myself and see if I can figure this one out so I can use my ViewSonic at its max resolution.

Hello, ya'll, I did a screen size change and figured out two files were changed: & another by the same name.

(don't remember it's full name... this is it's OS 9 name)

If you'll notice there are two entries: 768 and 1024, my current screen size. I set it to 870*1152 (my desired screen size) and had no success. Does anyone have suggestions?

Thanks, Eric.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist SYSTEM "file://localhost/System/Library/DTDs/PropertyList.dtd">
<plist version="0.9">
<br> &lt;key&gt;Mode&lt;/key&gt;
I noticed that file before, too, but I figured it just told the window manager what screen size to expect. I've got a feeling there's a different program involved in actually setting the monitor size, but damned if I know what it might be. This and that default blue desktop have been getting on my nerves.
Originally posted by rharder
After changing the plist file, did you log out and log in again?


Yes, I tried a few tactics:
1. change settings under OS 9.04 with BBEdit Lite 4.6 and boot into OS X
2. change settings under OS X with TextEdit, logout, login
3. change settings under OS X with TextEdit, restart

No success. What is interesting is that the files are *not* changed to 1024*768 on login/boot even though the screen size is set to 1024*768 (& when I press the monitor's preferences button it says it's running at 1024*768 @ 75 Hz vertical & [maybe] 67 kHz horizontal refresh rates, rather than the USER MODE HF: 68.5 kHz VF 75 Hz that shows up with 1152*870). Only when I change resolution in the Displays control panel do the two files get changed.

What I just found on a search is the following app and Overrides folder. Presumably this might provide a mechanism to override the Plug-and-Pray information returned by the monitor.


I think the DisplayVendorID is for Apple displays. Can anyone confirm?

Perhaps it's time that I contact KDS and see if they can help me with an override file (or else, there might be some adapter which will help kill the Plug-and-Pray signal between monitor and computer, thus forcing the Displays control panel to allow all possible sizes supported by my video card (which are 320*240 right up to 1900*1600 at 24 bit colour)).

Is the plug and pray signal carried by separate pins, or is it mixed in with the normal VGA signaling? If it's separate pins, just get yourself a couple foot long extension, and chop off the pins on the extension cable.
I've always thought using pnp with monitors was a dumb idea. You should have seen the mess that my physics teacher and I had trying to set up an LCD panel with a Compaq monitor in series.
Okay, I've done some experimenting, and I've found some promising results. It turns out that the monitor identifies itself by sending data over pins 4, 11, 12, and 15. I went to the computer store and bought a 15 pin monitor extension cable. With the help of Mr. Needle-Nose pliers, I ripped (quite literally) said pins out of the male end of the cable. I connected my monitor through the neutered extension, and the Mac OS had no idea what it was - I was free to select any resolution my card supported! Of course, some of them resulted in the monitor telling me "Out of Range," but I did get to select some new ones. The problem with the extension was that it caused a very noticeable degradation in signal quality, since it was 10 feet long, and not shielded very well. I think I'll go to Radio Shack and custom build a small de-plug-and-play pass through box. In theory, one could rip the pins directly out of the monitor's built in cable, but if you screw up, you're out a couple hundred bucks. If you feel like pursuing any of this crazyness, just don't hold me responsible. ;-)
Originally posted by davidbrit2
It turns out that the monitor identifies itself by sending data over pins 4, 11, 12, and 15. I went to the computer store and bought a 15 pin monitor extension cable. With the help of Mr. Needle-Nose pliers, I ripped (quite literally) said pins out of the male end of the cable... and the Mac OS had no idea what it was - I was free to select any resolution my card supported!<snip>If you feel like pursuing any of this crazyness, just don't hold me responsible. ;-)

I'm not keen to be playing with the monitor's cable just yet since it's got a three-year warrantee and I have a sneaking suspicion that ripping out a pin would void it! But, thanks for the info. There are little boxes that you can buy to do exactly what you are proposing to do (about 2" x SVGA connector) with dip-switches to determine what signals are sent through (a little less destructive than ripping out pins). I've been hesitant to go to such lengths b/c I'd rather the solution be a software one, rather than hardware. Besides, I'm not ready to switch to OS X... Apple will have to make the GUI faster before I switch (I would *kill* to be using it right now since I'm downloading in the background and don't want to be forced to do a restart in case of a crash)!!!

L8r, Eric.
How do you know which pins are 4, 11, 12 and 15? Mine aren't labeled. I will gladly rip the pins out of my monitor cable!!! As long as I know which ones. Could one of you guys make a diagram of this solution. I'll bet others would be interested as well.

Hi Sprague, you might want to shorten your signature a tad... it's longer than your message in lines.

Anyway, I found this at

SVGA DB 9 pin to High Density 15 pin Cable Pinout
DB9 pin Connects To Hi-Density 15 pin
PIN 1 = PIN 1
PIN 2 = PIN 2
PIN 3 = PIN 3
PIN 4 = PIN 13
PIN 5 = PIN 14
PIN 6 = PIN 6
PIN 7 = PIN 7
PIN 8 = PIN 8
PIN 9 = PINS 10, 11

Not exactly what your looking for, but it's here FYI (& FMI).

And, the pin-outs (which I grabbed from a PDF I d/l



You should also find pin #s on the connector itself. Often they're tiny little bumps which you'll find with a hand lens.

PS found a neat site in my searches:
Scott Mueller Library - Upgrading and Repairing PCs Quick Reference, Second Edition
(Publisher: Macmillan Computer Publishing)

And, for cables, take a look at:

This is great! Thanks for the time you spent on this. Now I can use OS X.

Also, I will make my sig. short. It is really long.
Hello everyone, I hope those of you who are suffering from this screen-size annoyance have subscribed to this thread for notification.

I actually have a (potential) $5 CDN ($3 US) solution to the problem of unwanted plug-and-pray signals. For $5.75 CDN I picked up a (new) male-female SVGA adapter (0.5 cm wide) from a local used computer parts store. What I'm going to do is pull the pins mentioned in an earlier post in the forum and see if that'll leave OS 9.1 and OS X 10.0.3 in the dark as to the identity of my monitor.

BTW The hack mentioned in the post before this one no longer works in OS X 10.0.3.

A male-female SVGA adapter is seemingly redundant, but apparently it is intended to protect a port from plug-in/pull-out damage of frequently replacing monitors.

That's more or less what I did. Pulling out the pins works just fine, but make sure that you remove the pins I mentioned earlier, or you'll ruin the video signal. I'm actually using this kind of setup right now.
Originally posted by davidbrit2
That's more or less what I did. Pulling out the pins works just fine, but make sure that you remove the pins I mentioned earlier, or you'll ruin the video signal. I'm actually using this kind of setup right now.

Ok, I pulled pins 4, 11, 12 and 15 from my SVGA male-to-female adapter and succeeded!!! My monitor is now simply recognised as a VGA monitor and I can chose whatever screen size I want within the limitations of the video card (ATI RAGE 128 16 MB). It is a simple solution and cheap without the problems of ghosting associated with extension cables. I used needle-nosed pliers to pull out the pins and it took a little effort. If your adapter is anything like mine it's a mold with little pins (about the length and size of a watch band pin) that have to be pulled out as a whole. You should be able to grasp the whole pin (on the pin side), clamp down without harming those around it, and pull the pin out (both the pin-out and pin-in side) with a solid pull (using leverage is a good idea). If you move the other pins a bit they shouldn't be harmed unless you knock them all out of alignment.

PS From an Apple PDF on a motherboard I got the following for the pins:


Please note that DCC is what was in the PDF. I suspect that it should refer to DDC. PDF: LPX-40_Dev_Note.pdf
Developer Note
Apple Logic Board Design LPX-40 (seems related to the PPC 6400)