Must a Sofer computer check his work?



I am a Sofer, I was wondering if it is a chiyuv to computer check my work or is it enough to go over it three times as mentioned in Shulchan Aruch?



According to most poskim there is no obligation to use a computer, although it is very recommended (obviously in addition to human checking).



ראה שו”ת קנין תורה ה, קו. תשוה”נ ב, צט. ג, שכו. משנ”ה י”א, קטו. אבל ראה שו”ת שבה”ל ז, ב.