Arduino mega 1280 usb port problem

Hi I got Arduino mega 1280 from eBay... u get the screen and stuff... and i used it on Linux, windows 7 and windows XP... on 3 different PC-s... on every one i was having problem... when i connect arduino on PC via USB i get it like a Unknown device (XP and W7) and one time i got it like a port (only time i was able to use it )... now i have only windows XP and i cant get it as an port... i have tried to install drivers FTDI and other stuff but it just does not work every time i get it as in unknown device...

what should i do... i don't get it... it WORKED once... but now it just doesn't recognize.... When i was on Linux it was working about 30% of time i connect it...

"Unknown device" (after drivers installed etc) means the communications between the host PC and the USB Device are not working properly, or the USB device is not working properly during the initial handshaking phase.

It's not just a "plug-in and run" situation. When you plug the device into a PC Host USB port, quite a bit of communications, handshaking and "Enumeration" goes on before you see it as a COM port.

And you say it worked 'once in a while'...

So, "Something's Flakey".. Rats! Harder than 100% fail sometimes.

You have to eliminate possibilities.

  • USB Cable?
  • Another Arduino of same USB type (FTDI) work OK??
  • Another Computer or O/S ? (You DID that )...
  • Another Mega??

Having more than one of everything to test with is more comfortable.

I buy Arduino clones out of the factory in China, but we test them 100% again after the factory test, BUT that only works when the USB chip Enumerates OK.. If they fail that they're rejected and sent back (VERY small % and maybe none so far??) I hate to think about where they'd go from there. Some guy on the street in Shenzhen sells a bag to some guy in Hong Kong with an Ebay store?? The Ebay store will replace it if you send it back, but it's a pain. If it's anything important, buy at least 2 (Statistically 3 is a lot better) of the same thing and test them all on receipt.

Let us know who this all works out. Where in the World are you?? Can you borrow any working FTDI Arduino to test with??

Good luck, and good testing...

Hi thx for response... i figure it out... problem is bad usb connector on Arduino :grin: so all i need to do is to insert cabal and to pull it out a bit or to the left so it makes a nice connection... so if any one is having problem like this... its cabal or usb port... like the Terry said "- USB Cable?"...

OK, Now you know WHAT is Flakey. Good work.

If another cable acts the same maybe you can resolder the USB connector.

Most of the boards out of Ebay / China look very good as far as build quality and soldering is concerned… How does yours look for build quality?

Glad you figured it out.

hello Ognjetina

can you tell me where you bought it?


well its not the cabal it self.. i used more than one... problem is on the connector of arduino... and yes it is EBay/China... it look fine build but i think the problem is inside of usb jack (pins are not touching good so it loses and gains connection several time in a sec and can't recognize device)... I'm thinking to buy new jack and replace it but for now I'm just having fun with arduinu (working on several projects like screen interface and servo controllers) so i don't have an urgent need of repairing it yet... like i said i just need to connect it few times and eventually it gets a nice connection and it works...

@ Massimo Banzi

i got it from EBay that shifts from Hong Cong China...


what's the name of the vendor?


here is the link:

[quote author=Massimo Banzi link=topic=50981.msg365274#msg365274 date=129694770] what's the name of the vendor? [/quote]

Hi Massimo,

First, Thanks and THANKS for all you've done for so many of us!

Second, if you'd like to talk about the Chinese/Hong Kong/ Singapore activity in Arduino and all the Open Source products, please get in touch. I've been researching this somewhat for a couple of years, I lived in Shenzhen for two years (But didn't know much about this then), and have a close Chinese friend who lives there now who I am working with.

Basically, many/most of the (many!) Hong Kong Ebay sellers don't know anything except where to buy boards JIT from Shenzhen.

Just type "Arduino xxx" into Ebay: 160 results found for arduino 328 243 results found for arduino KIT 129 results found for arduino duemilanove 37 results found for arduino uno 106 results found for arduino mega

... but a few really understand Arduino now, if you read between the lines of their Chinglish.

I'm just concerned that someone will throw the Gerbers at a second-rate factory back in the hinterlands somewhere and put out something with the word "Arduino" on it that looks like the circuit board from a Walmart toy.

The ones I have from a couple of the good Shenzhen(Futian) board houses look very good, physically. Some of the accessories like Electronic Bricks out of Beijing have really excellent build quality.

Your ideas are flying around the World at supersonic speed!!

And the Chinese guys like Eric at Seeeduino and Xiao at FlamingoEDA are doing some really nice work.

Regards from Saudi Arabia (wherever the heck THAT is...)

Sort of an update on the China-sourced Arduino question:

I have acquired and tested several "Arduino compatible" or "Arduino Open Source Copy" source boards (Disclaimer: I now sell some on my online site)...

They look pretty good. I have a MEGA board that was not done well or cleaned well..

I have tested about 40 boards recently with no failures.. (Test shield design and software are available here: )

For schools and people who need to keep costs down these are a decent choice. Examples here:

I suggest to people that they buy an original Arduino if possible, to support the development effort. And I usually use them for workshops I do.


Kindly try this link directly to the install drivers. A restart after install is recommended.

This thing worked for me.