Hotend too hot?

Hello, my print quality became very bad somehow. Prints are now brittle, fragile, not shiny and rough. Could it be hotend too hot? I am printing PLA at 190 degrees. Maybe it is thermistor issue? Thanks.
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Too cold.
Also, you might recheck your steps/mm and adjust your extrusion ratio [ie, my printer has proper steps/mm, but when printing with PLA the ext. ratio needs to be 0.9]

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

Thanks for quick reply. Extrusion steps/mm are calibrated, I get exactly 100 mms extruded after I request 100 mms. I was printing with same settings before, everything was ok, could it be thermistor? Or maybe the end of the plastic roll, so the PLA quality became worse?

Personally, I don't believe in aged PLA or ABS filament. I've stored mine in not a single clean or kept dry environment, just sat in whatever living room of the time. Over a year old and printing hasn't changed.
Could very well be that is the end of the roll though, not because of age but because of a bad manufacturer. Have you tried with a different roll or do you only have one?

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

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MrDoctorDIV
Personally, I don't believe in aged PLA or ABS filament. I've stored mine in not a single clean or kept dry environment, just sat in whatever living room of the time. Over a year old and printing hasn't changed.
Could very well be that is the end of the roll though, not because of age but because of a bad manufacturer. Have you tried with a different roll or do you only have one?

Just checked with another PLA, it is the same brittle print. Could it be my thermistor on the hot end shortening, because of poor isolation, so it shows not actual values? Or my heater cartridge broken in some way? In temperature graph, I see actual values, everything seems to be fine.

Edited 1 time(s). Last edit at 06/30/2014 12:40PM by Capinho.

Do you have an IR thermometer to verify temps? Have you checked the resistance in your thermistor?

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

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MrDoctorDIV
Do you have an IR thermometer to verify temps? Have you checked the resistance in your thermistor?

I will get the IR thermometer tomorrow, the resistance in thermistor is ok ( 80-100 kOhms)