Hebrew characters appear as question marks in a WP plugin

I’m using a WordPress plugin called Vertical News Scroller.
It’s working fine in English but when I write in Hebrew I get question marks.
I have no such problem with other plugins or genrally in my Hebrew locallized site.

This plugin has a table called wp_scroll_news.

In order to find what is the character set for this table I ran the following query:

SELECT CCSA.character_set_name
FROM information_schema.TABLES T, information_schema.COLLATION_CHARACTER_SET_APPLICABILITY CCSA
WHERE CCSA.collation_name = T.table_collation
AND T.table_name = "wp_scroll_news"

and I got:
latin1
latin1
latin1

So I used this query:

ALTER TABLE wp_scroll_news CONVERT TO CHARACTER SET utf8;

Then I checked again and this time I got:
latin1
latin1
UTF8

After restarting the (WAMP) server and writing new news I still get question marks.
I guess the two remaining latin1 need to be changed as well to UTF8.

How can I do that?