Smoke and Fire from my Smart LCD Cable ...

One of the extention cables that goes from the Ramps 1.4 to the Smart LCD controller got so hot
so it melted and burned down the plastic shield of the flat cable. And I have no clue why !

Suddenly white smoke when out of my idle printer and I was lucky to be very close and act fast.
The printer was idle and the ramps and arduino are all new. The printer worked just fine before that.
It is possible ( I am not so sure about ) that I have switched off the power supply so the only power source was from my USB cable.
Is that possible the current from the arduino to the smart controller have made that ?
BTW, the diode that required to operate the LCD was preinstalled on my Ramps right of the box.

Sad to inform you guys that there a new risk in town :-(
Anyone an idea ?

I might have an idea. Did you check that the rotary encoder is connected correctly? I have heard that it can cause shorts if wired to the wrong pins. Which pin was it that drew all of this current? I am an electronics engineer (in the making) and I would be more than willing to help fix this.

Edit: does the main controller for the printer still work? I wonder if the display backlight pulled too much current from the main controller, the main controller's voltage regulator popped, and then the smart controller blew up from it. Unplugged from the controller, If you have a multimeter, measure the resistance (both polarities) between the 2 wires that failed. I am wondering what happened in the controller.

Edited 1 time(s). Last edit at 02/19/2015 01:22PM by iamdarkyoshi.

Thank you for the interesting points

1. the rotary looks standard as it has arrived pee-soldered to the board as other panels do.

2. The arduino is dead, I got two led operated the on green and the orange pwm always on.

3. the burned wires are the one on each flat cable , the one that is closed to the red one.

4. Funny but the ramps + drivers are ok (with a new arduino installed).

5. I have to admit that I have extended the SD card reader module on the LCD panel so it will be accessed easily from the front printer panel. I may shorted a pin, not sure why or how.

The SD card slot may have done it. Measure resistance on the two wires that failed right at the LCD, desolder the sd card slot, and test again. Solder has irritating ways of ruining your day, and maybe it bridged a gap that wasnt within view. good thing this didnt happen on my printer as almost every part is flameable... right down to the cardboard box it is inside of O.o
I am kinda wondering if a voltage reg failed or not. Also, on my printrboard clone, there is a solder jumper that connects USB 5v to the board's 5v (so it can be programmed with the supply off) I desoldered the jumper. If I switched the supply off before, the USB attempts to run the entire printer! ...needless to say, it doesnt work. So I just removed the jumper. Not sure if this has anything to do with your problem. *Sigh* I run across so many unexplainable electronics failures. But hey, it is a learning experiance. I refer to it as the "vertical learning curve"
Hope you can get it running again, and I certainly willing to help. Also, I am planning on one of these (hopefully not) self-detonating smart controllers, and I want to know if my printrboard SD card reader can be used instead of one on the smart controller, because i could just design it using parts from my scrap pile.
Best of luck!

Problem solved and the reason seemed to be strange.

Check the attached photo, it seems that there is a different wiring between the green ramps and the red ramps and their compatible smart LCD.
Not sure why they are different at all but now with the new set of both red ramps and red smart lcd there is no problem at all.
I use the same SD card extension cable as before.

Bottom line, if you have a red ramps buy only the red smart lcd

i.e.
LCD
[www.aliexpress.com]
[www.aliexpress.com]
RAMPS:
[www.aliexpress.com]
[www.aliexpress.com]

Strange. ya wanna send me your old dead smart controller?

Sorry, only the cable lost :-)
the controller is fine sine I was very fast on disconnecting it.

Nice! Do you know if I could make one without an sd card reader, and use my printrboard's onboard slot?