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Active ADB extender?

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  • 68kMLA Supporter

I bought a 5m S-video cable with the naive expectation that it would be possible to put my 7100 in a cupboard. Unfortunately, it doesn't seem to work. Sometimes I can get the keyboard to turn the machine on, but it doesn't work after boot-up. I am running an Extended II, teardrop mouse, and a small Wacom tablet.


My first guess is that it's due to the voltage drop on the 5V line, and I was wondering I could modify my keyboard to take a 5V power supply in addition to ADB, but I'm not sure it's a good idea to connect a separate 5V supply to my computer... so I thought about making a small box with two ADB ports and a plug for 5V that didn't connect the 5V lines between the ADB ports, but powered the keyboard from a separate supply.


Or maybe it's not the power that's the issue, but noise or similar? I'm sure I've heard of people using long cables for ADB, but maybe they were special somehow?

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Video favors lower capacitance so some cables use extremely thin wires. 


ADB needs low resistance.  Go for heavier gauge wiring or build your own cable.


I would not add external power to the bus.


Measure the 5v delta at the end of the chain vs at the Mac and do the same for ground.

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