ADC Cinema display keyboard USB not working

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Level 1

6 points

ADC Cinema display keyboard USB not working

Hi,

I have an old Apple cinema display using an ADC (Apple display connector) that is plugged to a converter and DVI/miniDisplay port to a Thunderbolt port to the Mac Pro 2013.

Keyboard and mouse were plugged to the monitor, then the monitor USB cable was plugged to the Mac.

When I removed all cables and simply plugged keyboard and mouse directly to the Mac, the keyboard is completely not responding.

Any idea why?

Shutting down, unplugging cables from ports, reseting the PRAM, trying to load in safe mode is impossible because the keyboard is not working.

Connecting back the original wiring brings the keyboard back to life.

Very strange.

Posted on Apr 6, 2014 7:03 PM

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Answer 1

brun Author

Level 1

6 points

Apr 6, 2014 7:16 PM in response to brun

Well after leaving the Mac unplugged from all cables including power for an hour, the keyboard works directly plugged in the Mac. Probably a classic USB thing where it remembered being daisy chained to monitor and did not understand the direct connection. Any thoughts?

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Answer 2

Apr 8, 2014 2:37 PM in response to brun

The USB circuitry in Apple ADC displays often fails in interesting ways and can interfere with the operation of the computer. Leave the DVI to ADC adapter's USB cable unplugged for reliable operation. You will lose computer control of brightness, and the display's USB ports, but they are only USB 1.1 anyway.

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Answer 3

brun Author

Level 1

6 points

Apr 8, 2014 5:21 PM in response to Malcolm J. Rayfield

Thank you for the reply.

The USB 1.1 are not bad actually for keyboard and mouse, unless I am missing a drawback.

USB ports are always scarce, so I try to use them.

I will keep in mind that it is glitchy.

The brightness control does not even work when I plug it.

I thought the new Macs don't support that control interface perhaps.

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