A non-Jew who converts to Judaism after Shemini Atzeres, and he has a safek regarding mashiv haruach umorid hageshem – what are the rules for such a person?
For a regular Jew, within the first 30 days he repeats; afterwards, he does not repeat.
Should the convert count his 30 days from the day of his conversion? Would it make a difference if he was davening even prior to his conversion, even though he was not technically obligated to do so?
The idea over here is that if he said it for thirty days or 90 times, it becomes part of his tendency to say it that way and therefore we can assume that he said it the correct way. It doesn’t have to do with being obligated to say it or not. Therefore he should count thirty days from the time that he stated davening that way. It is known that people say a the words ” mechayeh meisim ato rav l’ hoshiah, maashiv haruach u’morid hagashem” 90 times in order to avoid these questions, even though when they said it they weren’t obligated to daven.
O”H 114 -9, M”Bibid 97