Does this help you ? It works on my machine.

DECLARE @s-2 varchar(10) = CHAR(153);

INSERT INTO Table_1 (sometext)

SELECT @s-2 UNION ALL

SELECT '1' UNION ALL

SELECT @s-2 UNION ALL

SELECT '2'

SELECT * FROM Table_1

UPDATE Table_1 SET sometext = REPLACE(sometext, @s-2, '?');

SELECT * FROM Table_1;

The first insert produces the following result:

[font="Courier New"]

sometext

™

1

™

2[/font]