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Jasen Betts[_2_] Jasen Betts[_2_] is offline
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Default USB Hub not working

On 2017-12-30, wrote:
I have one of these USB hubs with several USB connectors, which plugs
into a single USB port on a computer. It dont work. If I plug in a flash
drive directly to the computer, I can access that drive. But if I plug
it into the hub, the drive never shows up. I tried this on 3 computers.

I opened that hub, and there is a circuit board, with each output port
connected to a trace on the board which goes to a black dot on the
board. I dont know what that "dot" is, but I assume it's a chip of some
sort, and it looks like the dot itself was some sort of epoxy placed in
the board.

This was a gift, and it's going to get returned to the store, but I am
just wondering what kind of circuit this is?


The blob conceals an silicon chip mounted on the board this type of
construction is called "Chip On Board" or "COB" the chip does the
signal routing, translation, and forwarding and needed to support
USB hubbing

Until looking at the innards, I thought that these hubs were just a
direct connection to the input (from computer) USB. But I see there is
more to it....


Yeah, somehow they call it USB but electrically it's not what I would
consider to be a bus.

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