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Old Quadra, new monitor


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#1 Morrick

Morrick
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  • LocationSpain

Posted 14 February 2010 - 09:16 PM

Folks, I'm coming back to the barracks after a long hiatus, in the hope that someone can point me towards a solution.

The problem: I wanted to put a newish CRT monitor to good use by connecting it to my trusty Quadra 950. It's not an Apple monitor, so I used a DB15 Male to HD15 Female 10 DIP Switch MAC to VGA Adapter (this one exactly). I tried many of the dip switch combinations listed in the manual, but the only two results I get are:

1. No image.
2. I get the image with no distortions but instead of colours, everything has a green tinge.

I also have a second, simpler video adapter, with just one switch. The two settings are 21" Multi and VGA/G3. With either of these settings I see the image, but it's all green, like n. 2 above.

I understand it's mostly a case of trial-and-error, and that probably I'll have to try some combinations that are not listed in the manual (the examples are for old monitors) but I'm getting frustrated and I was hoping to hear from people in a similar situation if, and how, they managed to solve this issue. I'd hate to be unable to take advantage of such a beautiful monitor.

Thanks in advance!
Cheers
Rick
Go to the System Folder -- http://systemfolder.wordpress.com/

#2 H3NRY

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Posted 14 February 2010 - 10:09 PM

The green tinge is probably because the quadra is putting out sync on green, and the monitor isn't expecting that. The added sync signal boosts the zero (black) level on the green video signal. If one of the switches controls sync, set it for TTL sync, or turn off sync on green, or however they label it.

Alternately, if the monitor has the ability, set it to accept sync on green. I don't recall at the moment whether the 950's onboard video has the TTL-only sync option, but I think it does, because I used mine with a vanilla VGA CRT and one of those adapters with a dozen switches.

#3 Morrick

Morrick
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Posted 15 February 2010 - 11:29 AM

H3nry, thanks for trying to help.

The monitor has no apparent way to accept sync on green. I've navigated the On-Screen-Display menu and explored every possible setting, but most of them are related to screen geometry, position, colour temperature, moiré, degauss, contrast, brightness.

The leaflet for the video adaptor is located here (PDF file). My model is the first, "MAC/IBM ADAPTOR: 15DM/HF-10P", and I've tried every switch combination in MODE 6 (which according to the leaflet is for Sync on Green), but to no avail. The results are the same as in my previous post: either no image or green-tinged image. I even tried quasi-random combinations to see which switches trigger the image, but no change in the outcome.

It is very frustrating. I had managed to upgrade the RAM in the Quadra from 28 to 40 MB and was happy to revive the old beast in combination with this nice 19" monitor, so that I could get rid of the old 14" Apple Colour Monitor, which weighs like a car...

I could even look for another video adaptor, but in a situation like this how can one know if it works or not?

Cheers,
Rick
Go to the System Folder -- http://systemfolder.wordpress.com/

#4 Unknown_K

Unknown_K
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Posted 15 February 2010 - 01:55 PM

Go out and find a nice Sony Trinitron, they all seem to SOG just fine.
Favorites: big box Mac IIs, 950, 800's
Wanted: Anything Nubus, Video capture and editing hardware and software for 68k mac. Original software including A/UX.
Looking for 9150, Mac II, Color classic, 840av motherboard, and Nubus cards.

#5 H3NRY

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Posted 16 February 2010 - 02:33 AM

OK, try "mode 5 VGA 640x480" separate sync. Avoid mode 6, sync on green, is what I meant to say. If the picture won't stop rolling / tearing, the monitor may require SOG (mode 6) but you'll have to adjust the green cutoff level to compensate, and I don't know whether it's worth messing with.

#6 Morrick

Morrick
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Posted 16 February 2010 - 06:30 PM

Again, thank you H3nry for your assistance.

I've tried Mode 5 VGA 640x480 - separate sync. Result: green screen. I've tried Mode 5 on other resolutions: same old story. Either no image or green screen. I have even found another DB15/VGA adaptor with 6 dip switches and tried all the combinations with that one, too: same results as before.

I'm starting to think that there's no way to establish a nice relationship between my Quadra 950 and that monitor.

This morning I also found a RasterOps NuBus video card and inserted in one of the free slots, but I guess I'll have to find some kind of extension/control panel to make it work properly. The card is detected by the usual Monitors control panel, and I can set different colour depths and resolutions for the two cards (the Quadra thinks there's another monitor connected and displays a dual monitor arrangement in the Monitors panel), but every time I connect the monitor to the video port of the RasterOps card I get no image.

This is getting quite frustrating and it's starting to eat more time than I expected. I guess that I'll have to keep the old Apple 14" Colour Monitor for the Quadra (grr... only 640x480) and use this bigger monitor with the PowerMac 9500. :-/

Cheers
Rick
Go to the System Folder -- http://systemfolder.wordpress.com/

#7 H3NRY

H3NRY
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Posted 16 February 2010 - 08:05 PM

Phooey! I used a 21" SuperMac bottle with my Q950's built-in video, but it "just worked" so I never had to delve into the mysteries deeply. Next time I fire the old beastie up, I'll have to mate it with a VGA LCD, I expect, since the SuperMac monster went to Goodwill last year.




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