USB SDHC reader picky on ports

[mikeford]

We are long time micro SDHC users in phones etc, so we have a collection of USB readers both purchased and included with memory. So far the ones that were a buck incl shipping from various vendors work great, tested with up to 32GB chips, but a BUNCH of more expensive ones are very fussy on which ports we use.

I went round and round with Kingston after we purchased a batch of 8 and 16 GB micro SDHC kits, chip and two adapters flash and USB, to use as project completion gifts and found out much later many of the readers were flaky.

Anybody know what might be going on, different power on some ports, or maybe some kind of software driver issue?

Some drives work fine in all ports.
Some drives are only seen in some ports.

 

[razel]

It's probably just lack of QA. Things from China are cheap for that very reason. The consumer becomes QA.

The other thing is USB 3 ports do allow for more power (amps) if the device asks for it. I can imagine a USB 3 device with a lack of QA outright drawing too many amps from a USB 2 port which can cause it to overheat or just think it lost power because the voltage dropped too far below 5v.

 

[mikeford]

The buck shipped from China ones so far are the most reliable, its the Kingston and a Sandisk (red and black current model) that are giving me issues and all our stuff is pre USB 3.

It "feels" like a driver issue, but these are mix of XP Pro and Win7 systems, and I am not finding any "clues" about how it could be a driver.

Also its very repeatable about which ports work with the flaky readers, and all work with the cheapo's.