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Hi Glen,
As I am an RF engineer, I thought I would add my two cents.
I assume you are using well shielded cables for both USB AND power? And also large diameter cables for power in particular?
PWM controllers operate in the KHz band mostly. One thing, that could now be different when you moved things around, is the cable lengths used and the resistance in the power cables to the current surges that are seen each time the TEC is triggered by the PWM pulse train. Long cables could now be antennas, or simply transmitting the current switching back through the controller, into the laptop.
It could be a simple as grounding the cold finger, but if you didn't have the problem before you moved things around, and when you moved the USB hub and cables, if you changed any of the cables, I would concentrate on those areas first.
Last edited by sharptrack2; 14-12-2015 at 02:44 PM.
Reason: Clarification - meant to say TEC instead of fan.
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