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Quadra 950 vs Apple Multiple Scan 720 Display

stevenh

Member
I was hoping this monitor was going to have a Trinitron tube, but it turns out when I picked it up that it obviously wasn't.

http://www.everymac.com/monitors/apple/multiple_scan/specs/multiple_scan_720.html

Regardless, this worked fine with a PowerMac 7200, but the Quadra 950 can't go higher than 640x480.

I'm assuming the ROM for the Quadra 950 doesn't understand the model ID coming from the monitor and therefore defaults to a single lowest-denominator resolution.

My question: Can I hack the pins or the ROM or the Monitors control panel to override the listed options?

I seem to have found a link to SwitchRes from the Info Mac archives... I'll be testing this tonight also.

Has anyone dealt with newer Apple monitors on older Apple hardware before?

 

stevenh

Member
Howdy, AppleVision is definitely installed and I even tried the "Apple Multiple Scan Display" install disks, but these just seem to overwrite files that were already installed by Mac OS 8.

I then tried SwitchRes, but that didn't give me extra functionality.

After a little reading (http://www.bivalve.net/reference/tn/VideoCompatibility.html), it seems that this document indicates that the Quadra 950 with this monitor should be capable of all resolutions. I'm trying to work out if they just did the calculations based on available VRAM or if they are actually indicating that the monitor is compatible with this old Macintosh.

After a little more reading (https://users.soe.ucsc.edu/~davis/projects/mac/monitor.html) it seems that an incompatible monitor will show up as a 12" RGB fixed-sync. This is what is happening. This is why the 640x480@66.7 is showing up.

The tim manual here (http://tim.id.au/laptops/apple/legacy/quadra_900.950.ws_95.pdf) indicates that it supports Apple monitors and VGA. VGA means 640x480? I do note that the Quadra 950 was way before the 800 and 630 which have 'advanced' video.

One more bit of research (http://www.ralentz.com/old/mac/hardware/dale-adams/video-quad8-centris.html). Dale Adams was the guy who actually worked on the hardware. Would love to ask him for the exact answer :)

So, I tin-foiled the three sense pins and got it displaying the Apple 21S 21" 1154x780. But this is fixed sync too.

Leads me to wonder that at the time of Quadra 950 creation was there a multi-sync monitor that could do the range of resolutions I'd like?

I cannot find evidence anywhere that indicates exactly what the Quadra 950 is specifically capable of.

 
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beachycove

Well-known member
The Q950 can run a 17" monitor no problem, but.... Behind the power supply are VRAM slots. Check to see if they are filled.

 

stevenh

Member
VRAM is full. When i grounded the sense pins, it outputted 1152x740 perfectly fine.

My question is: Can the Quadra 950 use the 'extended sense pins' of the Multiple Scan monitors?

 
Last edited by a moderator:

stevenh

Member
Excuse the double-post.

If anyone wants to use an Apple Multiple Scan on an 'older' Macintosh then make sure you turn DDC OFF.

This can be done via the Information tab on the OSD.

Doing this and then cold-booting allowed me to select all the resolutions I wanted.

Well, up until 1024x768. I'm sure it's meant to be able to do 1152x780.

 
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