Teensy ++ 2.0 (not recognized by windows error 42) After Few Minutes

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devilhunter

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Greetings,

I decided to have fun with this chip yesterday, it worked for few minutes, then the computer stopped recognizing the usb, I tried 3 different computers ( 2 of them running windows 10 64bit and the other one windows 7 64bit). My second windows 10 computer detects the device as "Unrecognized USB", but it doesnt detect it anymore when I install the teensy drivers!

I should also note, Ive installed a voltage regulator prior to connecting teensy to my computers; additionally, Ive cut the 5v trace and bridged the 3v pads together.

I havent done any modification to the chip, in short, it worked for few minutes and stopped working afterwards. Ive also noticed, the cpu runs hot when Im connecting it to my windows 10 desktop pc.

Regards.
 
PaulStoffregen said:
Try the recovery process, where you hold the button while plugging in the cable. Details here:

https://www.pjrc.com/teensy/troubleshoot.html

Remember, Teensy uses HID, not serial, so look for the Teensy Loader to detect it. Or if looking in the Windows Device Manager, look for this (not serial):

https://www.pjrc.com/teensy/check_halfkay_vista.html
Click to expand...

Also, Ive noticed that the regulator is not providing 3.3v to the teensy, instead it mistakenly providing 3.8v, could this be the issue here? Any work around for it? Ive noticed it works for few minutes on my laptop before it shuts down. I have to wait 3-4 hours for the next attempt. Any clue?
 
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Running hot, needing to wait for it to work again and PCs not liking the board are all signs of high current draw. Using a breadboard or spliced cable to measure the current when fed from a DC supply may be useful. The IC can run on 3.8V, but the why for the 3.8 being present may be interesting. What resistance do you get with a multimeter between USB power and the regulator output when disconnected?
 
Also it might help to see pictures of your T2+, both top and bottom.

It might help show if the board may be a counterfeit? Also it might show if there are any obvious looking shorts.

Also maybe see exactly which Voltage regulator you used?
 
Again I have never used this board, and as
Such never setup to use at 3.3v

But pictures showing it done has solder jumper
On bottom of board from I believe from 3.3 and center pin?
 
KurtE said:
Again I have never used this board, and as
Such never setup to use at 3.3v

But pictures showing it done has solder jumper
On bottom of board from I believe from 3.3 and center pin?
Click to expand...

Thanks for the help mate, Ive cut the 5v trace (the one in between 3v pad & 5v pad)
 
Did you use a MCP1825 regulator? Was is purchased from PJRC, or some other source?

Many different 3.3V regulators exist on the market. They use two very different pinouts. If you substituted a different regulator with the other pinout, the incompatible connection would (probably) explain why this happened.
 
I bought this

MICROCHIP MCP1825S-3302E/DB IC, LDO VOLT REG, 3.3V, 0.5A, SOT-223-3

The first leg is 5v, the second is ground, the third is 3.3
 
PaulStoffregen said:
Yup, that's the right part.
Click to expand...

Any clue what to do next? Why the chip's core run hot in few seconds? Why it works for few seconds (less than 10secs) then it keeps disconnecting? Was it overclocked? How to revert back to default settings / flash if possible? Ive cut the 5v trace, could this be somehow affecting the functionality of the chip?

:confused:
 
Again others can answer more, but some of the things I would do is to check for shorts and near shorts... That is do you have some form of multi-meter?

If so try measuring the resistance between GND and VCC, GND and 3.3v, 3.3v and VCC. For good measure if nothing jumped out at you on those, I would check from all IO pins to GND...
 
KurtE said:
Again others can answer more, but some of the things I would do is to check for shorts and near shorts... That is do you have some form of multi-meter?

If so try measuring the resistance between GND and VCC, GND and 3.3v, 3.3v and VCC. For good measure if nothing jumped out at you on those, I would check from all IO pins to GND...
Click to expand...

GND - VCC is ~3.4v, what to check on IO? I simply filled the ports with solder, prior to that, everything was fine.

Any idea where to find refrence resistance?
 
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For something to get be getting hot you need something like at least 1/4 watt, where power = volts * current. Shuffle that around at 3.3 volts and you get P/V =I 0.25/3.3 = 0.070 or 70 ma. Ohms law R = V/I = 3.3/0.07 = 47 ohms. So in poking around anything between 1 and ~50 ohms would be of interest. <1ohm check to see that it really is supposed to be connected. General rule of thumb on an unpowered board would be investigate anything under 1k, and you also need to check for things that are supposed to be wires that show readings like 3 ohms due poor soldering, which can be all sorts of fun in completed projects but less likely to be where things are at here.

In this case given the way your regulator worked I suspect you have a cross connection with 5V from somewhere, so regulated output was getting pulled up. Is there any change in reg output voltage as things heat up? Regulator will clamp output when it over heats so you should see voltage start to drop.

Also which part/s get hot can be of interest in working out where the power is going, though as noted above the regulator may end up hot trying to feed a solder bridge elsewhere on the board.

So basic plan is to go round the board 3 times, looking for pins connected to
5V USB power
3.3V post regulator
gnd
Most of them should be in the Mohm, for the ones that are not look at the schematic and reference card and work out why.
 
GremlinWrangler said:
For something to get be getting hot you need something like at least 1/4 watt, where power = volts * current. Shuffle that around at 3.3 volts and you get P/V =I 0.25/3.3 = 0.070 or 70 ma. Ohms law R = V/I = 3.3/0.07 = 47 ohms. So in poking around anything between 1 and ~50 ohms would be of interest. <1ohm check to see that it really is supposed to be connected. General rule of thumb on an unpowered board would be investigate anything under 1k, and you also need to check for things that are supposed to be wires that show readings like 3 ohms due poor soldering, which can be all sorts of fun in completed projects but less likely to be where things are at here.

In this case given the way your regulator worked I suspect you have a cross connection with 5V from somewhere, so regulated output was getting pulled up. Is there any change in reg output voltage as things heat up? Regulator will clamp output when it over heats so you should see voltage start to drop.

Also which part/s get hot can be of interest in working out where the power is going, though as noted above the regulator may end up hot trying to feed a solder bridge elsewhere on the board.

So basic plan is to go round the board 3 times, looking for pins connected to
5V USB power
3.3V post regulator
gnd
Most of them should be in the Mohm, for the ones that are not look at the schematic and reference card and work out why.
Click to expand...

Thanks for your reply, the reading is fine now, 3.3 v across the input and GND, stills my teensy works for 5 min then disconnects, I checked the resistance between the 5v & 3v and found it to be ~160kohm

I bought another teensy, will test and report back.

Thanks again.
 
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