AXE027 USB cable failure

[noelnelson]

My AXE027 USB programming cable has just died. It just didnt work when the laptop was turned on and programming editor started.
Then, when I tried it in another USB port, Windows told me there was excessive load on the USB hub, and both my USB ports are now also dead.

Apart from seeking sympathy, has anyone experienced this or have a comment?
(ASE027 was plugged into laptop and the project, when laptop tuned on. And I have used the same cable for many projects)

I have previously noted that my picaxe project can re-boot sometimes when plugging in at the 3.5mm plug end, if the laptop is powered from the mains plug pack. I suspect the floating DC output from the laptop plugpack (Switchmode unit) is the culprit.

 

[neiltechspec]

Does your laptop PSU have an earth connection or just Live & Neutral ?.

It could be there is some AC content getting through which could destroy the AXE027. Check standing voltage - AC or DC with a multimeter.

Mine is on a desktop through a separate powered USB hub, when my PC starts up & shuts down it cause any connected PICAXE to restart.

Neil

 

[f2cf1g]

I had a cable go intermittent and then it died altogether. I cut into the jack plug and found a dry joint. Replacing the plug cured the problem. Maybe worth a try in your case also?

 

[bfgstew]

I accidently put 12v onto the download cable, albeit briefly, and it fried it on the spot.

New cable required methinks!

 

[Goeytex]

My AXE027 USB programming cable has just died. It just didnt work when the laptop was turned on and programming editor started. Then, when I tried it in another USB port, Windows told me there was excessive load on the USB hub, and both my USB ports are now also dead.

This is an unusual failure and the first time in 5 years that I have heard of a USB device (Axe027) blowing out a usb hub ( Motherboard). But as the saying goes, "What ever can go wrong will go wrong .... eventually.". That some tough luck though.
Hopefully it was not an expensive laptop.


USB hubs and mother boards are not all the same. Some are more tolerant of shorts/ faults than others. But no guarantees that if the USB VBUS is shorted to ground that the built in protection will actually work. I suspect that is what happened to your system.

It is for this reason that I purchased an optically isolated, powered USB HUB for working with various micro controllers and my home-brewed circuits. It maybe a bit of overkill, but it will protect the PC/Laptop from disaster. Better to lose an external hub than a motherboard.

You indeed have my sympathy .....

 

[noelnelson]

neiltechspec. Laptop plugpack didnt have an earth, it is double insulated. And so the output DC is floating. I also looked at my bench supply, it is also floating. So putting the 2 together, there must have been a large enough potential difference difference (pun intended) to destroy the AXE027.
$42 later for a new cable, $25 for a USB hub, and time spent being more careful on earthing (as in tieing common rails and connecting to anti-static bench mat), I carry on..

Also neiltechspec, as you say, "when my PC starts up & shuts down it cause any connected PICAXE to restart", I have experienced the same. Probably a sign that the floating voltages are upsetting the picaxe. I havent had a chip fail because of this, but it does worry me. I often work on these in a remote location so rather than risk any further faulure, I will make a grounding cable from the laptop to the battery system common, the serial port screw terminal is an ideal connection point.

cheers

 

[erco]

Condolences.

Two years ago, I turned on my desktop and a burning smell came out. One of my then 2-year old twins had stuck a coin into an open USB slot. This particular Compaq had a multi card reader module on the front panel. Turns out what fried was a thin PCB trace on the multi-reader (acted like a fuse) and there was no damage to the motherboard. I was lucky, I just bypassed the PCB trace with some hookup wire and everything worked fine again. Now I keep cables and SD cards plugged into all openings at all times to eliminate the temptation for the twins.

Card reader was like this one plus 2 USB slots: http://www.ebay.com/itm/HP-Pavillion-504857-001-P6000-Series-15-in-1-4-slot-Multi-Card-Reader-SD-/321317804403?pt=US_Memory_Card_Readers_Adapters&hash=item4ad0089973#ht_61wt_1166

 

[inglewoodpete]

I had trouble with the other end of an AXE026 cable (RS232 serial to PICAXE) when my children were (a lot) younger. The 3.5mm stereo plug got plugged in the computer's speaker socket. The (motherboard based) AC97 audio never worked again. Luckily, it was a desktop PC and I could get a PCI sound card!

Then there was the piece of toast that got poked into the VHS player....

I'm sure I must have caused my parents an equivalent amount of grief when I was very young.

 

[neiltechspec]

noelnelson.

The resets I see are due to the serin line changing state during PC startup/shutdown, fooling the PIC into thinking a download is starting.

When the PC is running, I can unplug / replace the programming lead from the PIC without any affect.

My PC is Earthed, the bench PSU I use, 0-30v @ 0-3amp, is a linear supply (house brick !) is also earthed. I have used the AXE027 on a laptop, but only running on batteries.

On a side note:

Try putting a multimeter between earth & the output of some of those cheapo far eastern switchmode PSU's - can be scary !!!.

I've seen one of those cheapo SMPSU's catch fire (12v @ 1a), one where the case melted before the internal fuse blew,
another generated so much RFI it killed a GSM gate intercom.

It seems the CE markings are meaningless for some of them.

There is a lot to be said for an old fashioned wirewound transformer (linear) PSU.

Neil.

 

[noelnelson]

Neil
Thanks, that serin answer totally explains that problem, which therefore isnt really a serious problem.
I know what you mean about cheapo SMPSU's. I have a TV Masthead amp that you dont disconnect the RG6 wall connector when its on for fear of a good tickle! I just didnt think that issue would be present on good HP laptop. lesson learnt.
cheers

 

[neiltechspec]

It shouldn't be on a decent laptop psu, like yours.

Still, like you say, lesson learned. Something I will bear in mind as well with laptops.

Neil.

 

[Hemi345]

Then there was the piece of toast that got poked into the VHS player....

Just the other day I noticed the subwoofer on our home entertainment system was sounding wierd. 16 screws later, I found a pair of socks, two rubber balls, a Hotwheels car, two Captain Barnacles, a plastic fork, and some Duplo blocks inside. Needless to say, the subwoofer is now up on a shelf where my two year old can't poke things into the port of no return.