Black screen with Kensington K33928 and Apple 20" ADC display

[mcng]

Hello,
I just acquired a Kensington Model M01063 Product # K33928 which I believe is a DL195, I'm trying to make it work with a Macbook Pro running 10.8.5 and an ADC 20" display connecting with the Apple DVI to ADC converter.
The ADC 20" display and DVI to ADC converter are working fine when connected to a mini display adapter.
No matter what I try, I got a black screen, I tried several plug in sequences, drivers from kensington then directly from DisplayLink versions 2.1 then 2.0 then 2.1 beta, no go. I performed deinstall reboot reinstall reboot each time I installed a different driver. I tried the different Macbook USB ports as well, still nothing.
I installed SwitchResX and exported EDID for the ADC through mini display port then through DisplayLink, (left is mini display port, right is DisplayLink), named it "display a" (see attachment).
Because I've got a second ADC 20" display here is it EDIDs diff as well, (again left is mini display in, right is DisplayLink), file is "display b" (see attachment).
Hope these could be of help to improve support of this model. Regards

[mcng]

Just tried with driver version 1.8 no luck either, as just other versions display is detected, System Preferences shows the right native resolution (1680x1050) but the screen is black.
Is it normal that after installing and deinstalling /var/tmp/ is not clean? I always find DisplayLink remains there with 1.8 there are libusb.lai and libusbpp.lai libs with upper versions deinstaller app, deinstaller archive and others things?

[mcng]

After installing and deinstalling version 1.8, usbpp.h is not removed from /usr/local/include/

> find / -name usbpp.h 2>/dev/null
/usr/local/include/usbpp.h

and

ls -la /usr/local/include/usbpp.h
-rw-r--r-- 1 root wheel 24428 13 jui 2012 /usr/local/include/usbpp.h


usb.h is there as well, and libusb-0.1.4.4.4 is not removed too.
I also found remains of driver 2.x in /usr/local/lib/ (libusb-1.0).
Do I need to remove them to avoid conflicts?

[mcng]

Went to a friend who has a VGA display, the adapter works fine…

[mcng]

An interesting quote from Jason Fitzgerald of Gefen (Product Manager) at http://forum.gefen.com/topic.asp?TOPIC_ID=5795 about the 15" ADC, maybe if fixing the EDID doesn't work this can be helpful?

There was an issue with the sync polarity with the 15" ADC displays. We tried to recreate your setup here at Gefen and, unfortunately we were unsuccessful in any attempt to get this to work in this combination. Even with the firmware in the VGA-2-ADC where the sync polarity is reversed produced unreliable and unviewable results. While most computers could resolve this issue internally via a direct connect, it seems as though the placing of the USB to VGA device in the chain prevents any type of polarity sync correction to be applied. All firmware on the VGA-2-ADC failed to display an image on the Apple 15" display. Unfortunately there is no fix for this yet.

[mcng]

Note that using an Apple DVI to ADC could be quiet different than using a Gefen or Dr Bott so the reversed sync polarity could work with these.

[mcng]

Would be nice to have a compatibility status on ADC displays by the way…

[mcng]

Adapter confirmed working with a Nec display through DVI.

In the end, this clearly means that after testing with one early manufactured Apple Cinema Display 20" ADC (acrylic) and one late manufactured Apple Cinema Display 20" ADC (acrylic), connected with Apple DVI to ADC, Displaylink DL195 chip is not compatible with this model.

So, the informations in your FAQ are false and misleading ("Only one resolution is available for use when an Apple Cinema Display is connected to a DisplayLink device.") by suggesting all Cinema Displays shall work, please update these for this model.