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Jailbreaking the Apple Display Card 24AC . . .

Trash80toHP_Mini

NIGHT STALKER
. . . or so it would seem.

I hope the folks at LEM don't get the notion that I'm picking on them, but I've found more info that's missing/apparently mis-posted/ incorrect.

LEM lists the Resolutions for the Radius PrecisionColor Pro 24AC as:

. . . standard Mac resolutions from 640 x 480 to 1152 x 870 in 24-bit color . . .. . . It is the same card as the Apple Display Card 24AC.
This is exactly what my testing has borne out in the DeclROM Swap Diaries of my Pet IIfx.

However, the Table of resolutions listed there for the Apple Display Card 24AC appear to be in error. The list is consistent with resolution testing I've done of the Radius PrecisionColor Pro 24X which LEM specifies at:

512 x 384 to 1152 x 870, as well as 800 x 600 and 1152 x 882, all in 24-bit color . . .. . . It is the same card (or very nearly the same card) as the Apple Display Card 24AC
I don't have the Radius PrecisionColor Pro 24AC, but I'd like to get one or have reports from someone who has one!

My sneaking suspicion is that the PRO 24X was exactly the same card, re-released and branded under the new name, upgraded with the more capable PC_24X DeclROM of 1994.

Mind that: all my testing of the has been done under 7.5.1 which has been exceedingly stable and handled everything that I've thrown at it. I've tested a LOT of NuBus cards in this config. and I'm NOT going to changing that config any time soon.

ISTR LEM's baseline OS as being 7.5.5 for their Guide to NuBus Video Cards, so YMMV.

Long story short, the RPCP_24X has two key resolutions, apparently missing in the capabilities of Apple's 24AC. I cannot coax these resolutions out of either Card when hobbled by the 24AC_1.1-Rev from either Apple Display Card 24AC

Missing 24AC resolutions:

_800 x 600 x 24bit @ 60Hz

1024 x 768 x 24bit @ 60Hz

I say these are key resolutions because that sync rate is expected by the vast majority of LCDs available today, the latter having been standard for 15" LCDs since back in the day. The former should scale perfectly onto my 1600 x 1200 Dell MultiSync.

I've only tested under the 7.5.1 Monitors Control Panel using sense code settings for VGA/SVGA and Apple 19" w/o driver specific support using the trusty ENHANCE "Liberty Adapter," so YMMV under another config. (I actually hope it does, but I doubt it! [:)] ]'> )

ADC_24AC-P24X_640x480.jpg

ADC_24AC-P24X_800x600.jpg

ADC_24AC-P24X_1024x768.jpg

Reverting to the original ROM/DeclROM at both VGA/SVGA and 19" 1024 x 768 settings on the sense lines:

The Apple Display Card 24AC yields results consistent with developing DeclROM Jailbreaking Theory.

Apple_24AC_60Hz_VGA.jpg

 
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