Go Down

Topic: My Uno is too hot for TV (Read 749 times) previous topic - next topic

eddiea6987

Sep 30, 2011, 08:52 am Last Edit: Sep 30, 2011, 09:37 am by eddiea6987 Reason: 1
This baby just died on me, and i do not understand why?
I plug it in via USB it turns on for a second and slowly fades off and the regulater get really hot really quick, and i do not use this board for anything other then sampling code
now im thinking of popping in  a good old 7805 to see if that would fix it... might it work?

i just need to know the pin out of the regulator on the board..

opps its not the regulator that gets hot its that fuse right next to it

..and now it is working fine.. i will keep an eye on it though..

mods can delete this if they would like though i would like to know what that fuse is for in the first place..?
I could print the Arduino logo on a box of cereal and sell it as "Arduin-O's"

westfw

If the fuse gets hot and shuts off the arduino, that means that the board is consuming too much power.  Usually this would be due to some sort of short between the power rails, and would happen relatively quickly.  That it happened slowly in your case is relatively mysterious...

eddiea6987

perhaps it was turning off quickly i was basing the "slowly" comment on the power led, it slowly faded out
I could print the Arduino logo on a box of cereal and sell it as "Arduin-O's"

James C4S

Quote
That it happened slowly in your case is relatively mysterious...

The poly fuse is designed to heat up and create an open circuit.  Even in cases of dead shorts, it is possible for some current to continue to flow while the poly fuse heats up.  It isn't a perfect system for catching shorts and doesn't "trip" to an open state.  It does take some time for the internal elements to warm up and expand.


Quote
now im thinking of popping in  a good old 7805 to see if that would fix it... might it work?
i just need to know the pin out of the regulator on the board..

If you have a regulated supply, just apply power to the 5V pin on the Arduino board.  As for the pin-out of the on-board regulator, the schematics for all Arduino boards are available on the Hardware page.
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

marklar

Does it do this when nothing is connected?  If no - what is connected when it does do this?

eddiea6987

there ws nothing connected to it at all it was jsut the board it self and powered by usb , i think however it may just have been perhaps sweat or something on the board amking behave like this because i just left it alone for a while and everything was back in order,
I could print the Arduino logo on a box of cereal and sell it as "Arduin-O's"

MarkT

Perhaps a small piece of metal had stuck to the board causing a short for a while?  It doesn't take much to bridge between surface mount chip pins...

Another possibility is one of the chips went into latch-up mode (a problem with all CMOS chips especially if you force signal pins above Vdd or below Vss)  This would clear on power-down.
[ I won't respond to messages, use the forum please ]

Go Up