Arduino Forum

Using Arduino => Installation & Troubleshooting => Topic started by: Kghunt on Jan 05, 2013, 11:20 am

Title: fried my uno (whoops) fix.?
Post by: Kghunt on Jan 05, 2013, 11:20 am
I accidentally fried my uno by putting a 12v supply into 5v instead of vin.

Obviously it now does not work but I am just wondering how hard it would be to fix and what is likely broken.

As it stands its not recognised by the pc anymore (a given) but I can still power it via the jack (but it gets hot). I used my usb ttl adapter to upload blinky and that worked (but the led is very dim prob fried).

Is it the usb chip? Or the overvoltage protector. Im assuming the regulator is ok as it still puts out 5v but is probably getting hot because there is a short on the power lines somewhere.

I have a nano and a pro (chinese versions) and a boarduino I made myself but the Uno is the only official board I have and I paid £18 for it. I wouldnt bother with it but I have sheilds for the uno.

any ideas where to start?
Title: Re: fried my uno (whoops) fix.?
Post by: pico on Jan 05, 2013, 11:36 am
There are two uC chips on the the Uno, the main 328p and the 8u2 (or similar) for the USB support.

You will almost certainly have fried both of them.

If you have a socketed 328p, you will be able to replace it with another. The smd 8u2 chip is not a practical replacement, though.

In this situation, if nothing else was damaged, you will get a Uno that can be programmed via the ISP pins, or via serial using an external USB->TTL serial converter.  The USB connector on the board may be usable for powering the board, but nothing else. You may find the fancy power source auto switching circuit has gone out to lunch as well, though, as it employs an op-amp, which may or may not have survived (many op-amps can tolerate 12V no problem, though.)


Title: Re: fried my uno (whoops) fix.?
Post by: Kghunt on Jan 05, 2013, 07:18 pm
i might use my last proto sheild to make a nano to uno adapter so i can use my sheilds.
Title: Re: fried my uno (whoops) fix.?
Post by: oric_dan on Jan 05, 2013, 09:18 pm
Your goose is cooked, buy a new goose for the holidays. They don't cost all that much.
Title: Re: fried my uno (whoops) fix.?
Post by: Kghunt on Jan 05, 2013, 11:06 pm
never mind. In the interests of recycling etc there should be a place where arduino boards go to die. for every 5 or so boards there may be enough salvageable componants to make a fully working "B" grade arduino that could be donated to a school.
Title: Re: fried my uno (whoops) fix.?
Post by: oric_dan on Jan 05, 2013, 11:15 pm
Not really. When boards with a lot of surface-mount chips get toasted, it's really not
worth the trouble to try and fix them - unless you're a really compulsive individual.
Toast is toast.
Title: Re: fried my uno (whoops) fix.?
Post by: Kghunt on Jan 05, 2013, 11:42 pm
just seems like such a waste. Im gonna harvest it for all I can get. USB and power jack, voltage reg (which I will test on breadboard) momentary switch and all the headers. Maybe even the dil. All these items I have purchhased at one timemor another.
Title: Re: fried my uno (whoops) fix.?
Post by: smeezekitty on Jan 06, 2013, 12:36 am
=( I just fried my Duemillanove today. I connected the ground to an oscilloscope that had the case ground shorted to the AC line.

*FLASH* *POP* followed by half the room losing power

After disconnecting everything and resetting the breaker, everything was ok except the Arduino.

The FTDI is fried...

I have actually had success using drag soldering to replace the FTDI chip but it did significantly damage the board so I cannot fix it at this point.

As far as the OP's problem, if they have a small soldering iron, small solder and a flux pen, they might be able to fix it although the 8U2 has an even finer pitch than the FTDI chip. Overall, I think they will need to purchase a Arduino like I will need to.

Bad day for Arduinos I guess  :P
Title: Re: fried my uno (whoops) fix.?
Post by: oric_dan on Jan 06, 2013, 04:47 am
Quote
I just fried my Duemillanove today. I connected the ground to an oscilloscope that had the case ground shorted to the AC line.


This is interesting. Were you powering the Duemilanove from the USB port on your PC?

I just did some tests on my notebook PCs. The USB shields and ground pins on the FTDI
cable seem to be isolated from the AC Mains. I don't see see how that could blow the
mains breaker.
Title: Re: fried my uno (whoops) fix.?
Post by: rvasque on Jan 06, 2013, 04:53 am
Maybe kitty's house is mis-wired at one of the outlets? That's the only explanation for your breaker popping.

I'd call an electrician.
Title: Re: fried my uno (whoops) fix.?
Post by: smeezekitty on Jan 06, 2013, 07:08 am

Quote
I just fried my Duemillanove today. I connected the ground to an oscilloscope that had the case ground shorted to the AC line.


This is interesting. Were you powering the Duemilanove from the USB port on your PC?

I just did some tests on my notebook PCs. The USB shields and ground pins on the FTDI
cable seem to be isolated from the AC Mains. I don't see see how that could blow the
mains breaker.

This was on a desktop but my laptop is the same. The USB ground is connected to the mains ground.

Quote

Maybe kitty's house is mis-wired at one of the outlets? That's the only explanation for your breaker popping.

I'd call an electrician.

No miswiring AFAIK. The scope had a fault that is now fixed.
Title: Re: fried my uno (whoops) fix.?
Post by: oric_dan on Jan 06, 2013, 07:37 am
What do you mean the scope had a fault, that's now fixed. That sounds like
very low probability.
Title: Re: fried my uno (whoops) fix.?
Post by: smeezekitty on Jan 06, 2013, 09:58 am

What do you mean the scope had a fault, that's now fixed. That sounds like
very low probability.


It is a very old scope (mostly vacuum tube).
One of the incoming AC wires was literally touching the metal outer case. It is properly insulated now
The cord I was using was not grounded  :smiley-mr-green:
Title: Re: fried my uno (whoops) fix.?
Post by: oric_dan on Jan 06, 2013, 07:23 pm
Wow, that is an old scope. Don't get a hernia trying to carry it around! Just for
general use, you might look at getting one of the inexpensive microcomputerized
devices, eg,

http://www.makershed.com/DSO_Nano_V2_0_p/mkseeed11.htm

Title: Re: fried my uno (whoops) fix.?
Post by: Kghunt on Jan 19, 2013, 09:52 pm
I finally binned my uno. Recieved my nano from china bay and it has a dodgy reset switch. I can replace it so I got a part refund. It ended up costing me £5. I think I may get another nano from the UK also as the buid quality on thisnone is questionable.