Major problem, need help asap

Hi all, im in desperate need of your talents, so ive finshed building my prusa mendel, hooked up the ramps 1.4 with LCD and the ardunio, uploaded the firmware, the LCD lit up with the temps etc, opened up pronterface and connected to the printer, no problem, tested all the motors and everything moved as it should, looking good, told it to go to the home position and as soon as it hit the end stop the whole lot stopped, i looked over and the LCD had every part of it lit up all at once (i.e no writing, every dot was on), so i disconnected the power, released the endstop and connected the power back up, does the exact same thing, screen lit up like a christmas tree, no writing, cant connect to it via computer, it sees the ardunio in the device manager but says it failed to start, so heres the interesting part, i removed the 12v supply and the screen went back to normal, had the temps on, i could connect to it via the computer, looking good, so i reconnect the 12v supply, loses connection, screen goes full brightness with no writing, now ive removed all the connections to the ramps board i.e endstops etc and even removed the stepper motor drivers but the same thing happens, ive removed the ardunio board and connected it to the computer and it seems to be working, not sure whats going on, any ideas?

Sounds like your EndStops are shorting out the system.

Are you using Mechanical Switches for EndStops?

Are they wired correctly?

Hi, im using mechanical endstops, ive tried powering the board without the endstops but it does the same thing, I doubled checked and I think I wired the endstops a row to low, the diagram I was working off showed 2 rows of pins on the board but my ramps board has 3 rows of pins with the bottom row have a + symbol on it, not sure if that's whats happened

**UPDATE**
Just tried powering the ramps board without the endstops/stepper drivers/steppers/heatbed/heatbed attached and noticed some smoke, I pulled the power straight away but I couldn't tell where the smoke came from, I removed the ardunio board and tested that separately and that still works so the smoke must have come from the ramps board, any idea what might be smoking?

Not good news. All circuits run on smoke, under pressure, and run fine as long as the smoke does not escape. You want to unplug all power, pull your shields and look for any blackened or discolored areas on any of the individual boards. Look on both sides and use a magnifying glass, I use STRONG readers for electronic work. If you are really lucky you just popped a pololu and they are only around 10 bucks each. You may even be able to replace the individual component on the board if it is just one thing and easy to find at say a radio shack or something. You want to remove all wiring and start again, carefully when you get things back together, because it sounds like something was mis-wired, or you may have a bad component. Limit switches are easy to check with a meter, other components are a little trickier. Once you get things disassembled, perhaps you could post a close up in sharp focus, one of us may notice something... Hope this helps.

Ive looked at the board and i cant see any burnt components on it, i tried reconnecting the power and this time no smoke, the arduino board is detected by the computer still but then says 'device failed to start' whenever i connect the 12v supply to the ramps board, is there any way i can test the arduino and ramps boards to see which is working and which isnt? if i can identify which one is the faulty party then i can replace that one, im still leaning towards it being a faulty ramps board as i can upload to the arduino and it shows up on the display but the screen fills up with blocks as soon as the ramps board is powered (regardless of whether the stepper motor drivers are connected), im working on uploading some pictures for you to look at but im having issues with file sizes

It sounds like the ramps board may be the culprit then, or a driver. If the arduino is recognized by itself, then your software configuration sounds basically correct, the ramps is the common issue. There are only a few parts on the board, a diode, some transistors and fets, and the 2 large capacitors. the rest is pins. I'd start by comparing like components to each other with an ohm meter. BTW, Gimp is an excellent free alternative to photoshop if you wish to edit or resize your photos.

Hi, thanks for the reply, ive attached afew photos of the boards and how it responds when the 12v is attached and when its not, i'll broken out the multimeter but so far everything seems to be okay on the ramps board, if anyone spots something ive missed or have any suggestions on what i can check feel free to shout out

BTW on the picture of the ramps board you'll see where the endstops connect to has 3 rows, i think the endstops connect to the top 2 rows and i think i connected them to the bottom 2 rows, as the error occured as the head touched the endstop im guessing its shorted something, but not knowing what the bottom row of pins were for im not sure

If you connected the wrong two rows on the end stops you shorted it out.

Your mechanical switches shorted the 5V+ and Ground.

I'll have to check the schematic to see what could have burnt as a result of doing this.

EDIT: Yup, looks like you blew VCC which looks like its a regulated +5VDC source from the Arduino itself.

So you have 2 choices.

Replace the Arduino, or hack in your own 5V regulator.

Edited 1 time(s). Last edit at 05/06/2013 01:48PM by ShadowRam.

Hey shadowram, thanks for your help, so your saying that by accidently connecting the endstops to the bottom set of pins (+5v rail) that it actually damaged the arduino board and not the ramps board? if thats the case then im lucky you spotted it cos i nearly ordered another ramps board, its a shame cos the arduino still works and accepts code but obviously the part that connects to the ramps board is shorted if im understanding it correctly

I just got done buying a bunch of electronic parts on ebay from Tayda2009 who does bulk individual parts dirt cheap. Many are 99 cents free ship. I mention this because you could probably get a new voltage regulator for a buck and fix your arduino. If you do this, cut the leads close to the component on your old regulator before attempting to desolder it. It is a whole lot easier that way and you wont be as likely to damage the lands on your circuit board. I like 25 watts for such work.

That might not be a bad idea, ive seen ''2 x SMD SMT LM1117 AMS1117 Voltage Regulator 5V 800mA'', would they do the trick?

Yeah it should do the trick.

You aren't pulling a lot of current on these 5V lines, it's mostly just for signalling.

But you should find the pins on the Arduino first while it is plugged into the USB, and make sure my theory that those 5V Supply pins aren't working is correct.

How would i go about finding that out? im guessing id using a multimeter to check the pins of the voltage regulator?

Just checking it now, if i use the earth on the left pin and and check the other test probe on the middle/right/top pins i get 4.88v, if i try any other combo i get 0v, does that sound right?

okay forgive me if this sounds stupid, im trying to teach myself electronics as we go, right, if im correct, looking down at the voltage regulator you see 3 pins, the left pin is input, middle pin is ground, right pin is output, if i measure the input and ground pins i get 4.88v, if i measure the ground and output i get 0v

That sounds like the problem. If you check the wiki on the arduino,[arduino.cc] it has the diagram. You want to power the board thru usb or the psu input, and not the power pins on the board for testing, as the power pins bypass the voltage regulator and doing so could further cause damage if out of range. Also, you really want at least around 7 volts coming in for things to work properly. (12 max)

Right okay, i'll order a voltage regulator and attempt to repair the board, so am i right in assuming that when the regulator is working correctly (powered by the usb) it should have multimeter readings on both the input and output pins?

You should just grab yourself a 5v wall transformer like an old phone charger and try supplying 5v to the 5v input of the RAMPS board to see if you have burnt out anything else and confirm it works before waiting to have parts delivered that may not fix the issue and waiting as long as it would take to get an entire new set of electronics.

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where would i attach the 5v to the ramps board? the main power inputs are 12v?

Assuming it's a linear voltage regulator, you will need more than 5v on the input to get any output. The +5v on the Arduino is derived from the USB connector which is already regulated, so I don't see why another regulator would be necessary to deliver +5v to the RAMPS board. I also don't see why it would work just fine with the +12v switched off, but fail when it's switched on. Have you tried switching the +12v on first, and then plugging in the Arduino? I've noticed that the Arduino is very sensitive to EM noise and the turn-on transient of my PSU is sometimes enough to mess it up. The 5v circuit is working fine or else your display wouldn't work at all.

yeah its defo a weird fault, ive tried connecting it in multiple ways, usb first, then 12v, 12v, then usb, results have been the same

Have you tried disconnecting one of the 12v pairs and seeing if that works?

I would probably not connect/disconnect any shields under power. And sheck is right, you really need a minimum of 6 to 7 volts input. If you are getting less than 5 volts you may or may not get output, however since your USB seems otherwise to be working, I don't think that is the problem. Also realize that when you have a power supply (which I am assuming you have tested with a volt meter) hooked up, the power from your USB is redundant. USB will run your arduino all day, but when you start adding loads, I think you are are good for maybe <800mA? So in practice, you need a working throughput from a full power supply to print with. I believe the voltage regulator is a key piece on the arduino. Side story about voltage regulators- In my younger days I once worked a concert with George Thoroughgood and the Destroyers. (Bad to the bone) As the techs were setting up, a voltage regulator failed in a power supply connected to the stage lighting. Within seconds, an $80,000.00 lighting console was up in flames. Pretty impressive for a 2 dollar part, eh? So they are important.

Ok,

So you measured 4.88V. That's good. No need to go buy anything yet.

EDIT: Sorry, I though you measured this at your EndStop connection points, but re-reading it looks like you read this off a 5V regulator not attached to anything. Check the 2nd picture attached and measure VCC while the USB is plugged in.

If you are getting 5V at VCC, then across the board is getting 5V.

Most likely it's getting this regulated voltage from the USB.

But when you connect the 12VDC, the board dies.

Do you have Diode 1 installed on the RAMPS?
See attached for location

If so, remove it.
This will prevent the 12V from going to the Arduino.
This means that you will not be able to run the printer without it hooked up to the USB.
(Which isn't a problem unless you have an SD Card setup anyway)

The Arduino and everything else will rely on the USB 5V instead of the Arduino trying to convert 12V to 5V

Edited 4 time(s). Last edit at 05/07/2013 10:29AM by ShadowRam.

If you ever want to run stand alone using LCD and SD card then I don't recommend running off the USB 5V.

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Wörth am Rhein, Germany
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rhmorrison Wrote:
-------------------------------------------------------
> If you ever want to run stand alone using LCD and
> SD card then I don't recommend running off the USB
> 5V.

Right, but he doesn't have much a choice, unless he wants to buy a new Mega 2560

And even if he did want to use these later without buying a new Arduino, he could just hack an old USB cord in half, and wire a 5V Regulator to the USB Power inputs, and power the Arduino through the USB.

The arduino wouldn't know any better if the 5VDC was coming from an actual computer or not.

Edited 2 time(s). Last edit at 05/07/2013 09:37AM by ShadowRam.

Quote
ShadowRam
Right, but he doesn't have much a choice, unless he wants to buy a new Mega 2560

Why that?
Worst case all he needs is to add an LM7805 to his circuit to derive the 5V from his 12V supply.

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

rhmorrison Wrote:
-------------------------------------------------------
> > Right, but he doesn't have much a choice, unless
> he wants to buy a new Mega 2560
>
>
> Why that?
> Worst case all he needs is to add an LM7805 to his
> circuit to derive the 5V from his 12V supply.

No.

If he does that, he could ruin the board even more. You don't want to backfeed 5V into the Arduino.

For him to hook a 5V into the VCC connection, he would have to find and cut a few parts of the circuit.

He's already said he's new to electronics, and I don't think he wants to go through that process.

Edited 1 time(s). Last edit at 05/07/2013 10:01AM by ShadowRam.