Peculiar ramps shorting problem

Ive recently completed my first reprap, and after a couple of weeks of getting some really nice results out of it I stupidly shorted the RAMPS board around the end stop terminals while the printer was on... DOH!. since then i am still able to turn the printer on and it will behave normally for a while, then usually after about 10-15 minuets everything looses power, and the voltage controller on the arduino starts to heat up rapidly. ive since replaced the RAMPS board and i'm having the same issue, whats strange is the controller always seems to turn off when i press the button on my smart controller, although it has also turned off without me touching a thing. the arduino seems fine and behaves normally when plugged into the pc. Any advice on this would be much appreciated, im getting pretty frustrated at this point Thanks!

Anyone any ideas on this? i cant work out why it would work fine and then appear to short out of nowhere, i noticed that the voltage controller is getting a bit warm when its working before it turns off, is this normal? then gets realy hot when it 'shorts'... ive tried it with 2 arduinos now and the same thing happens

Might there be some intermittent short in one of the end stops, or some small wire/metal piece inside the end stop pin headers that could cause a short from 5V to ground?

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fisher
Anyone any ideas on this? i cant work out why it would work fine and then appear to short out of nowhere, i noticed that the voltage controller is getting a bit warm when its working before it turns off, is this normal?

Are you running an LCD screen off the 5V rail? If so, then it is normal for the regulator to run warm because of the current taken by the LCD backlight - especially if the LCD is the 12864 graphics type, which takes about 100mA backlight current. In my designs, I generally power the backlight from the input voltage (e.g. 12V) via a series resistor, to keep the dissipation in the voltage regulator reasonable.

I guess it's possible that the short you had has damaged the voltage regulator, which now gives up when it gets warm enough. Although the voltage regulator is supposed to be short-circuit protected, I've seen other posts say that if you miswire the endstop switches so as to cause a short between +5V and ground, the voltage regulator often fails.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

A bad solder joint could also be a possibility. Things are fine when cold but once it's ran for a while and heated up, things expand and no longer make proper contact and then open up completely...or things expand and short out completely.

Have you tried selective use of freeze spray on the board? Even canned air sold as a dust removal agent at Staples can work if you hold the can upside down . NOTE You must have the applicator straw in place and use short directed bursts.