Why is my brand new USB SX Key HOT!!!
fiveslo
Posts: 40
I just received my brand new USB SX Key today, when I plug the key in my available USB port, Windows does it usual "bling bling" sound and when it first did, it claimed to install drivers, anyways maybe 30 seconds later, the dang USB Key becomes very hot, so hot in fact that I had to drop it, because if the clear heat shrink wasn't around the whole board, it felt like you could almost be burned by it... I immediately disconnected the USB Key, and pulled it from the Pro Dev board, tried again with USB Key disconnected... The same thing happened... this can't be good... Oh yeah, the USB cable that goes from the computer port to the SX Key, that too was new and ordered from the Parallax website, this can't be normal????????
Comments
Please note that it is important to not let Windows install any drivers. Instead, you need to install the VCP drivers from FTDI BEFORE connecting the SX-Key USB to the computer the first time. When you install the new SX-Key IDE for the SX-Key USB, these drivers will be installed automatically.You need to install this new IDE version anyway because older versions do not work with the SX-Key USB. You can download the software from the Parallay WEB site.
Normally, the SX-Key USB should not become remarkably hot, although I had the same effect one day when - due to a short circuit - a high current was passed through the SK-Key USB's Vss pin through to the PC's ground. I first thought I had fried the Key when I noticed that it became hot, but the next day (with the short removed), it worked again as usual.
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Greetings from Germany,
G
I downloaded the FTDI Drivers from Parallax, and tried installing them, all to the same dismay, the one thing I did not mention is that I did initially instal the latest and greatest SX-USB software, all prior to my installing the SX-USB Key, in any case, each time I try to download a program into the SX, with the 'new' SX-USB Key, I get· "SxKey Error Dialog box" stating "Vpp generation failed" clicking OK gets you a "Download Successful Box" funny since it doesn't work...
The target SX28 is good and so is the Pro Dev Board since I have managed to revive my old SX Key with the DSub 9 Pin connector and when I try to download to the same SX28 it works fine... also I have noticed that when I plug both SX-Keys in simultaneously.. in the Run... Configure area both SX-Keys can be selected, in other words the software is seeing both Keys...
The SX-USB comes to temperatures of 162 degrees fahrenheit measured with my Raytek laser temp reader, not something you could honestly hold comfortably in your hand.... ·the hottest part of it appears to what looks like a small coil that is near center of board towards the left hand side, with the USB port facing upwards, also this is with the USB-SX Key not connected to anything, except the computer USB port...·No possibility of external shorts since it does this when it disconnected as well as connected to my Pro Dev Board....
As Guenther stated I installed the "new" SX software that supports the SX-USB.... I just checked "Device Manager" and found that the manufacturer of the driver for, in my case, COM4 port, is FTDI, and is "Working Properly" according to at least the Windows Device Manager... too bad the "Manager" can't sense temperature... [noparse]:([/noparse]· What I also found surprising is the fact that while in the Windows Device Manager for COM4, in my case, is that Windows knows when I pull the SX-USB in and out of the USB port, since it detects when it is connected and when its not... interesting.... now why the heck doesn't it work, and gets HOT!!!!!· My feelings for its a defective SX-USB are growing...
Also, pardon, but I have to ask: Are you sure you plugged the SX Key into the header the right way around?
-Phil
I definitely will call tech support, by gently you mean with a "ten pound sledgehammer" smiling... that surface mount stuff, I leave to the pros... Anyways looking at the USB Key through a magnifier, that yellow thing, who knows what it is, just to the right of the coil, has begun to turn brown, as if its the shorted component and is "cooking" quite nicely... just don't look right... Plugged into header right... you mean when I plug it into the Pro Dev Board, well the component side of USB Key is up, which from what I see I think is correct???? OSC1 and OSC2 match up at least by the markings on the USB Key....either way this USB Key warms up with or without being plugged into the Pro Dev Board....
That "brown thing, formerly colored yellow" might be a tantalum capacitor that got installed backwards, has too low a voltage rating, or — most probably — is simply a defective component. But any of these would be consistent with the other symptoms.
-Phil
Post Edited (Phil Pilgrim (PhiPi)) : 8/18/2008 5:44:48 AM GMT
Whatever it is, but your estimation of being a tantalum capacitor would probably be correct, anyways, I've unplugged it for now, seeing as I have better uses for my USB ports, than heaters to keep my coffee warm... [noparse]:)[/noparse] .... In any case later today, as I'm typing this email at 1:16AM... I will contact tech support and see what they say...
after all your descriptions, I can only assume that your SX-Key USB is damaged by some reason. When you try to program an SX, and the message "Vpp generation failed" comes up, this tells you that the SX-Key could not generate the programming voltage Vpp (about 12V) on the OSC1 pin. The SX-Key generates this voltage but also monitors itself if it could successfully generate it. If not, it returns an error state to the IDE causing the error message to be displayed.
Possible reasons for no Vpp generation are:
- SX-Key-internal failures, like shorts, damaged driver transistor, or a bad or backwards installed filter capacitor.
- Short or high load on the target's OSC1 pin which pulls down Vpp. This can happen when you plug on the SX-Key in wrong orientation, or when some device, like a clock generator is connected to OSC1.
As you could successfuly program the target with a serial SX-Key, I don't think that the target causes the problem. So you better contact Parallax tech support for help.
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Greetings from Germany,
G