Extrution Problems 2

The temperature is too big, so the filament melts before entering the nozzle, so the extruder cannot push it no more. Lower it to 220-225 and it will do. Also, you can lift just a liiiiitle bit the top cover so fresh air can enter the chamber. But just a little bit. Try this and let us know.

Try 210. With top cover half opened.

Ironically this is the problem that I have right now too. The outside reading (I assume you use and infrared thermometer) its possible to be lower (so, in your case it might be the correct one). For instance, my extruder temp shows 100-1500 C when I start the printer (instead of 22-23C), thats why the temp I use for extruder is only closed to what it should be. Anyway, another solution (I had that problem too) was to print with mainboard outside the printer (do it at your own risk!!!). I get the mainboard outside, then placed a fan over the driver of the extruder. It stopped some of my problems back then. As for your problem it is about  small tweaks you can apply like those above. For instance, open all the doors and see whats happens. Get used to this kind of problem, I had them since day 1 .

At me, blowing air to the extruder driver ensured that there are no gaps (steps skipped, wich were visible seen on the printing). After all I didnt managed yet to print since last broke, but at least I know the cause. Anyway, you can try new things: print at higer speed (60-70 mm/sec).

100 degrees off is a lot. Measuring temp of something that small is tricky.
To see if you're in the right ball park: if your hot end is reading 240, you should be able to met a bit of filament on the outside of the nozzle. If it melts, its definitely not at 100C.

An IR thermometer averages over an area that spreads out the further you are from it (often a 60 degree cone). The built in laser pointer just shows you the center area.

A thermocouple can be quite accurate - at measuring the temperature of the thermcouple. That has its own drawbacks, including atually getting the thermocouple to the same temperature as what you want to measure. (Your tea kettle will be quite close to 100C, but casually touch the probe to it reads a lower temp.)

To answer your question though - there's a set of tables in the firmware source and one is chosen at compile time. To change the curve you need to pick another table, recompile and reflash the system board.

@trayracing;
thank you for your quick reply! I have used two different type of thermometer; 1-Infrared 2-Touch Pin. I believe the touch pin is more accurate, and even the touch pin thermometer read almost 80C  low.
On the other hand, I found that the set screw for the thermocouple affects on the reading as well, which is caused by pressure applied by set screw, i believe.
On the other hand, since the extruder melts some filament, i assume the temp reaches to a certain value in the extruder/block. And i understand that nature of the faulty/error of measurements.
However, i am so desperate that the printer stops at the middle of the printing. I was able to print only one model since i got my printer 8 months ago. I am not using it very often, but any time when i need it, i need to make tons of re-search and modification to be able to print a model.

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Go to solidoodle's home page, under software, look for Repetier 85B.  Auto bed leveling routine is embedded in the 85b version from Solidoodle, in later versions, you would have to add the routine to Slice3r, that's why I still use the 85b version.   Learning curve is short, just adjust your settings in Slice3r, and go.  ,Example-nozzle diameter .4, filiament diameter .3, extrusion multiplier 1, 2 tops 2 bottoms, 2 perimeters.  Also check z lift, and change to .5.  Acceleration setting from 9000? to 900 makes your machine run much smoother.  Remember to save your settings in slice3r after each change, give your new settings a new name, and select  your new settings in Repetier.  I also uncheck auto cooling as In Repetier, you can slow down or speed up your print. Using flow rate, you can control the extrusion value until it works well.  I set speed to 80 to start prints, and adjust up or down to my liking.
You could also go to Repetier's home page and read up on the host, but you want to d/l it from Solidoodle.  Give it a try as it will make your 3d printing experience better.