ramps 1.4 registering very high temperatures

Just got a new ramps 1.4 I've been trying to set up. Repetier 0.90 loaded onto the board fine and I can connect to the board via the repetier host. However, when I tried to power the board, it immediately disconnected from my pc, I wired it up as per the instruction on the ramps wiki page with black to - and yellow to +
I disconnected the power supply and was able to reconnect to the board. it now shows temperatures on the bed and extruder around 200C, even with nothing connected to the board! I took the ramps shield off the arduino and it still registers these temperatures! has anyone else had similar problems or an inkling of how to fix this?

Sounds like you've fried the Arduino somehow.

You will probably find that you have a short between the hot end heating element and one pin on a thermistor input.

Did you have the hot end or heated bed hooked up at all?

If you unplug the thermistors from the Ramps, you should see 0C type readings. You *may* also trigger a minimum temperature error (it's telling you the thermistor is unplugged...). If you still see 200C with no thermistor attached, that's not a real good sign.

yeah, that's what I thought. I grabbed a new arduino mega clone and it is doing the exact same thing though, could it be the repetier client somehow or maybe the pins are all mixed up?
This is my configuration in the pins.h setup, I havn't touched it since I downloaded it
#if MOTHERBOARD == 33
#define MOTHERBOARD 3
#define RAMPS_V_1_3
#elif MOTHERBOARD == 34
#define MOTHERBOARD 3
#define RAMPS_V_1_3
#define AZTEEG_X3
#endif
#if MOTHERBOARD == 3
#define KNOWN_BOARD 1

//////////////////FIX THIS//////////////
#ifndef __AVR_ATmega1280__
#ifndef __AVR_ATmega2560__
#error Oops! Make sure you have 'Arduino Mega' selected from the 'Tools -> Boards' menu.
#endif
#endif

// uncomment one of the following lines for RAMPS v1.3 or v1.0, comment both for v1.2 or 1.1
// #define RAMPS_V_1_3
// #define RAMPS_V_1_0

#ifdef RAMPS_V_1_3

#define X_STEP_PIN 54
#define X_DIR_PIN 55
#define X_ENABLE_PIN 38
#define X_MIN_PIN 3
#define X_MAX_PIN 2

#define Y_STEP_PIN 60
#define Y_DIR_PIN 61
#define Y_ENABLE_PIN 56
#define Y_MIN_PIN 14
#define Y_MAX_PIN 15

#define Z_STEP_PIN 46
#define Z_DIR_PIN 48
#define Z_ENABLE_PIN 62
#define Z_MIN_PIN 18
#define Z_MAX_PIN 19

#define E0_STEP_PIN 26
#define E0_DIR_PIN 28
#define E0_ENABLE_PIN 24

#define E1_STEP_PIN 36
#define E1_DIR_PIN 34
#define E1_ENABLE_PIN 30

#define SDPOWER -1
#define SDSS 53
#define SDCARDDETECT 49

#define LED_PIN 13
#define FAN_PIN 9
#define PS_ON_PIN 12
#define KILL_PIN -1

#define HEATER_0_PIN 10
#define HEATER_1_PIN 8
#define HEATER_2_PIN 9
#define TEMP_0_PIN 13 // ANALOG NUMBERING
#define TEMP_1_PIN 14 // ANALOG NUMBERING
#define TEMP_2_PIN 15
#define E0_PINS E0_STEP_PIN,E0_DIR_PIN,E0_ENABLE_PIN,
#define E1_PINS E1_STEP_PIN,E1_DIR_PIN,E1_ENABLE_PIN,


#else // RAMPS_V_1_1 or RAMPS_V_1_2 as default

#define X_STEP_PIN 26
#define X_DIR_PIN 28
#define X_ENABLE_PIN 24
#define X_MIN_PIN 3
#define X_MAX_PIN -1 //2

#define Y_STEP_PIN 38
#define Y_DIR_PIN 40
#define Y_ENABLE_PIN 36
#define Y_MIN_PIN 16
#define Y_MAX_PIN -1 //17

#define Z_STEP_PIN 44
#define Z_DIR_PIN 46
#define Z_ENABLE_PIN 42
#define Z_MIN_PIN 18
#define Z_MAX_PIN -1 //19

#define E0_STEP_PIN 32
#define E0_DIR_PIN 34
#define E0_ENABLE_PIN 30

#define SDPOWER 48
#define SDSS 53
#define LED_PIN 13
#define PS_ON_PIN -1
#define KILL_PIN -1
//#define SCL 21
//#define SDA 20

#define E0_PINS E0_STEP_PIN,E0_DIR_PIN,E0_ENABLE_PIN,
#define E1_PINS


#ifdef RAMPS_V_1_0 // RAMPS_V_1_0
#define HEATER_0_PIN 12 // RAMPS 1.0
#define HEATER_1_PIN -1 // RAMPS 1.0
#define FAN_PIN 11 // RAMPS 1.0

#else // RAMPS_V_1_1 or RAMPS_V_1_2
#define HEATER_0_PIN 10 // RAMPS 1.1
#define HEATER_1_PIN 8 // RAMPS 1.1
#define FAN_PIN 9 // RAMPS 1.1
#endif

#define TEMP_0_PIN 2 // MUST USE ANALOG INPUT NUMBERING NOT DIGITAL OUTPUT NUMBERING!!!!!!!!!
#define TEMP_1_PIN 1 // MUST USE ANALOG INPUT NUMBERING NOT DIGITAL OUTPUT NUMBERING!!!!!!!!!
#endif

// SPI for Max6675 Thermocouple

// these pins are defined in the SD library if building with SD support
#define SCK_PIN 52
#define MISO_PIN 50
#define MOSI_PIN 51
#define MAX6675_SS 53

#ifdef AZTEEG_X3
#define SDSUPPORT true
#define SDCARDDETECTINVERTED false
#define SDCARDDETECT -1
#define FAN_PIN 4
#define FAN2_PIN 5
#define LIGHT_PIN 6
#define BEEPER_PIN 33 // Activate beeper on extension shield
#define BEEPER_TYPE 1
#endif

#endif

I downloaded teacup and ran it with pronterface, it is also registering crazy temps except in Fahrenheit now (like steady 870) it is possible my pc fried the board? also would it be a terrible idea to attach the ramps shield to the board with the thermistor headers plugged in to see if that makes a difference?
Edit: I plugged it in anyway, weirdly the temperature readings are now down to around 190.5 still high but what the hell? surely without anything plugged in it should be open circuit, how could the pins register more resistance with the shield plugged in?

Edited 1 time(s). Last edit at 11/14/2013 12:11PM by blabberjack.

What dirves pins.h is the stuff in configuration.h. Depending on what motherboard you have set it'll do all sorts of odd things.

With no Ramps on the Mega, there is no pull up on the ADC input that connects to the thermistor. The only thing you will read is leakage currernt. That reading could be just about anything at all. The Mega reads the thermistor by using a bridge circuit to convert the resistance to a voltage. That's why shorting (or opening) the thermistor pins is a usefull diagnostic. You get max or min voltage on the ADC input. If you don't see a swing from min to max, either you are on the wrong input, your pull up resistor is fried, or the adc input is blown.

Ah, that sounds like good news! I have a new ramps shield coming because I suspect I blew the first one somehow or it just shipped broken so I will let you know when it arrives : )

There's not a whole lot to a Ramps board. Other than the FET's, it's basically a big bunch of jumper wires. If it's blown you should be able to see a scorched trace, a bum solder joint, or a bad connector. It's at least worth looking at while you are waiting for the new board.