I've been buying NodeMCU/ESP8266-12EX units from a seller on eBay.
There have been four. Two had the flimsy Micro-USB connectors broken off.
Two stopped being recognized by my laptops.
The latter seems more than a coincidence. Is there a fuse on the boards?
One unit will execute the last programmed sketch when powered up, but will not be recognized by my laptops.
I'm beginning to suspect a quality control issue.
The units are only about four dollars each but seem more expensive in the long run.
Has anyone else had this problem? Has anyone had long term programming usage from one of these units?
The very cheap ones are not built to the same standard as the more reputable branded ones. They often use inferior counterfeit components, and the manufacturing quality control can often be poor.
Yup, Bought a Esp32 a couple of months ago. loaded a few test programs on it , then got distracted from it when i was gifted a couple MKR WiFi1010's. Pulled it out last week and it was so corroded it looked like I had left it out in the snow all winter. needless to say windows didn't recognize it at all. In the trash it went.
OTOH I have used dozens of el cheapo Nano's over the years and never once had a problem.
You pays your money and you takes your chances.
This is why I don't buy components from eBay unless I am happy for them to be absolute junk. Sometimes you get lucky, its a complete lottery for stuff like this - I've had no issues with LM2596 buck converters for instance, but I bought a 12V->24V stepup converter that was a complete joke for instance. They is no quality control from most of the suppliers on eBay it seems. Many of the unscrupulous suppliers have dozens of pseudonyms to crowd out the good folks, and of course undercut in price too...
BTW I'd advise never buying individual semiconductors from such untrusted sources, they are commonly fake, pulls or factory-rejects (audio transistors and any ICs for instance are particularly common scams). And it should go without saying that mains PSUs should be sourced from trusted suppliers only.
Update: I found the devices were not at fault, except for the cheap USB connectors, and a hot glue gun took care of that.
The problem turned out to be the cables. I had several cables from other eBay purchases. They were included in the purchase of some other device.
They turned out not to work for signal applications. I tested all my cables of that type and came up with three. I tested them with all 4 (now 6) ESP8266s and all worked, even the ones with a USB connector replaced by a FTD232RL USB to serial adapter.