How to check for Non-Ascii Characters

Ranges in the pattern syntax use the sorting rules of your collation.

Use a binary collate clause so the range is ordered by character code.

(I also changed it to LIKE as I find that more obvious than PATINDEX > 0)

SELECT *      
FROM mbrnotes      
WHERE LINE_TEXT LIKE '%[' + CHAR(127)+ '-' +CHAR(255)+']%'  COLLATE Latin1_General_100_BIN2

If you're like me and you've gotten tired over the years searching for these characters in your company's terrible data, you can use this function or rewrite it for your own purpose. It's admittedly wordy, but it goes the extra step of identifying special characters if you want - uncomment lines 19 - 179 to do so.

If the string does not contain non-printable or extended ascii values - it returns NULL.

CREATE FUNCTION [dbo].[Find_Invalid_Chars]
(
    @SearchString VARCHAR(8000)
)
RETURNS VARCHAR(8000)
AS
BEGIN
    DECLARE @CharPosition INT, @CharVal VARCHAR(100), @ReturnVal VARCHAR(8000) = '', @isValid BIT = 1 -- Start as valid

    SET @CharPosition = 1

    WHILE @CharPosition <= DATALENGTH(@SearchString)
    BEGIN
    IF (ASCII(SUBSTRING(@SearchString, @CharPosition, 1)) NOT BETWEEN (32) AND (127))
        BEGIN
            SET @CharVal = '[' + CAST(ASCII(SUBSTRING(@SearchString, @CharPosition, 1)) AS VARCHAR(3)) + ']'
            SET @isValid = 0
            ---- Non-Printables
            --SET @CharVal = REPLACE(@CharVal, '[0]', '[NUL]')
            --SET @CharVal = REPLACE(@CharVal, '[1]', '[SOH]')
            --SET @CharVal = REPLACE(@CharVal, '[2]', '[STX]')
            --SET @CharVal = REPLACE(@CharVal, '[3]', '[ETX]')
            --SET @CharVal = REPLACE(@CharVal, '[4]', '[EOT]')
            --SET @CharVal = REPLACE(@CharVal, '[5]', '[ENQ]')
            --SET @CharVal = REPLACE(@CharVal, '[6]', '[ACK]')
            --SET @CharVal = REPLACE(@CharVal, '[7]', '[BEL]')
            --SET @CharVal = REPLACE(@CharVal, '[8]', '[BS]')
            --SET @CharVal = REPLACE(@CharVal, '[9]', '[HT]')
            --SET @CharVal = REPLACE(@CharVal, '[10]', '[LF]')
            --SET @CharVal = REPLACE(@CharVal, '[11]', '[VT]')
            --SET @CharVal = REPLACE(@CharVal, '[12]', '[FF]')
            --SET @CharVal = REPLACE(@CharVal, '[13]', '[CR]')
            --SET @CharVal = REPLACE(@CharVal, '[14]', '[SO]')
            --SET @CharVal = REPLACE(@CharVal, '[15]', '[SI]')
            --SET @CharVal = REPLACE(@CharVal, '[16]', '[DLE]')
            --SET @CharVal = REPLACE(@CharVal, '[17]', '[DC1]')
            --SET @CharVal = REPLACE(@CharVal, '[18]', '[DC2]')
            --SET @CharVal = REPLACE(@CharVal, '[19]', '[DC3]')
            --SET @CharVal = REPLACE(@CharVal, '[20]', '[DC4]')
            --SET @CharVal = REPLACE(@CharVal, '[21]', '[NAK]')
            --SET @CharVal = REPLACE(@CharVal, '[22]', '[SYN]')
            --SET @CharVal = REPLACE(@CharVal, '[23]', '[ETB]')
            --SET @CharVal = REPLACE(@CharVal, '[24]', '[CAN]')
            --SET @CharVal = REPLACE(@CharVal, '[25]', '[EM]')
            --SET @CharVal = REPLACE(@CharVal, '[26]', '[SUB]')
            --SET @CharVal = REPLACE(@CharVal, '[27]', '[ESC]')
            --SET @CharVal = REPLACE(@CharVal, '[28]', '[FS]')
            --SET @CharVal = REPLACE(@CharVal, '[29]', '[GS]')
            --SET @CharVal = REPLACE(@CharVal, '[30]', '[RS]')
            --SET @CharVal = REPLACE(@CharVal, '[31]', '[US]')
            ---- Extended Ascii
            --SET @CharVal = REPLACE(@CharVal, '[128]', '[€]')
            --SET @CharVal = REPLACE(@CharVal, '[129]', '[]]')
            --SET @CharVal = REPLACE(@CharVal, '[130]', '[‚]')
            --SET @CharVal = REPLACE(@CharVal, '[131]', '[ƒ]')
            --SET @CharVal = REPLACE(@CharVal, '[132]', '[„]')
            --SET @CharVal = REPLACE(@CharVal, '[133]', '[…]')
            --SET @CharVal = REPLACE(@CharVal, '[134]', '[†]')
            --SET @CharVal = REPLACE(@CharVal, '[135]', '[‡]')
            --SET @CharVal = REPLACE(@CharVal, '[136]', '[ˆ]')
            --SET @CharVal = REPLACE(@CharVal, '[137]', '[‰]')
            --SET @CharVal = REPLACE(@CharVal, '[138]', '[Š]')
            --SET @CharVal = REPLACE(@CharVal, '[139]', '[‹]')
            --SET @CharVal = REPLACE(@CharVal, '[140]', '[Œ]')
            --SET @CharVal = REPLACE(@CharVal, '[141]', '[]]')
            --SET @CharVal = REPLACE(@CharVal, '[142]', '[Ž]')
            --SET @CharVal = REPLACE(@CharVal, '[143]', '[]]')
            --SET @CharVal = REPLACE(@CharVal, '[144]', '[]]')
            --SET @CharVal = REPLACE(@CharVal, '[145]', '[‘]')
            --SET @CharVal = REPLACE(@CharVal, '[146]', '[’]')
            --SET @CharVal = REPLACE(@CharVal, '[147]', '[“]')
            --SET @CharVal = REPLACE(@CharVal, '[148]', '[”]')
            --SET @CharVal = REPLACE(@CharVal, '[149]', '[•]')
            --SET @CharVal = REPLACE(@CharVal, '[150]', '[–]')
            --SET @CharVal = REPLACE(@CharVal, '[151]', '[—]')
            --SET @CharVal = REPLACE(@CharVal, '[152]', '[˜]')
            --SET @CharVal = REPLACE(@CharVal, '[153]', '[™]')
            --SET @CharVal = REPLACE(@CharVal, '[154]', '[š]')
            --SET @CharVal = REPLACE(@CharVal, '[155]', '[›]')
            --SET @CharVal = REPLACE(@CharVal, '[156]', '[œ]')
            --SET @CharVal = REPLACE(@CharVal, '[157]', '[]]')
            --SET @CharVal = REPLACE(@CharVal, '[158]', '[ž]')
            --SET @CharVal = REPLACE(@CharVal, '[159]', '[Ÿ]')
            --SET @CharVal = REPLACE(@CharVal, '[160]', '[]]')
            --SET @CharVal = REPLACE(@CharVal, '[161]', '[¡]')
            --SET @CharVal = REPLACE(@CharVal, '[162]', '[¢]')
            --SET @CharVal = REPLACE(@CharVal, '[163]', '[£]')
            --SET @CharVal = REPLACE(@CharVal, '[164]', '[¤]')
            --SET @CharVal = REPLACE(@CharVal, '[165]', '[¥]')
            --SET @CharVal = REPLACE(@CharVal, '[166]', '[¦]')
            --SET @CharVal = REPLACE(@CharVal, '[167]', '[§]')
            --SET @CharVal = REPLACE(@CharVal, '[168]', '[¨]')
            --SET @CharVal = REPLACE(@CharVal, '[169]', '[©]')
            --SET @CharVal = REPLACE(@CharVal, '[170]', '[ª]')
            --SET @CharVal = REPLACE(@CharVal, '[171]', '[«]')
            --SET @CharVal = REPLACE(@CharVal, '[172]', '[¬]')
            --SET @CharVal = REPLACE(@CharVal, '[173]', '[]]')
            --SET @CharVal = REPLACE(@CharVal, '[174]', '[®]')
            --SET @CharVal = REPLACE(@CharVal, '[175]', '[¯]')
            --SET @CharVal = REPLACE(@CharVal, '[176]', '[°]')
            --SET @CharVal = REPLACE(@CharVal, '[177]', '[±]')
            --SET @CharVal = REPLACE(@CharVal, '[178]', '[²]')
            --SET @CharVal = REPLACE(@CharVal, '[179]', '[³]')
            --SET @CharVal = REPLACE(@CharVal, '[180]', '[´]')
            --SET @CharVal = REPLACE(@CharVal, '[181]', '[µ]')
            --SET @CharVal = REPLACE(@CharVal, '[182]', '[¶]')
            --SET @CharVal = REPLACE(@CharVal, '[183]', '[·]')
            --SET @CharVal = REPLACE(@CharVal, '[184]', '[¸]')
            --SET @CharVal = REPLACE(@CharVal, '[185]', '[¹]')
            --SET @CharVal = REPLACE(@CharVal, '[186]', '[º]')
            --SET @CharVal = REPLACE(@CharVal, '[187]', '[»]')
            --SET @CharVal = REPLACE(@CharVal, '[188]', '[¼]')
            --SET @CharVal = REPLACE(@CharVal, '[189]', '[½]')
            --SET @CharVal = REPLACE(@CharVal, '[190]', '[¾]')
            --SET @CharVal = REPLACE(@CharVal, '[191]', '[¿]')
            --SET @CharVal = REPLACE(@CharVal, '[192]', '[À]')
            --SET @CharVal = REPLACE(@CharVal, '[193]', '[Á]')
            --SET @CharVal = REPLACE(@CharVal, '[194]', '[Â]')
            --SET @CharVal = REPLACE(@CharVal, '[195]', '[Ã]')
            --SET @CharVal = REPLACE(@CharVal, '[196]', '[Ä]')
            --SET @CharVal = REPLACE(@CharVal, '[197]', '[Å]')
            --SET @CharVal = REPLACE(@CharVal, '[198]', '[Æ]')
            --SET @CharVal = REPLACE(@CharVal, '[199]', '[Ç]')
            --SET @CharVal = REPLACE(@CharVal, '[200]', '[È]')
            --SET @CharVal = REPLACE(@CharVal, '[201]', '[É]')
            --SET @CharVal = REPLACE(@CharVal, '[202]', '[Ê]')
            --SET @CharVal = REPLACE(@CharVal, '[203]', '[Ë]')
            --SET @CharVal = REPLACE(@CharVal, '[204]', '[Ì]')
            --SET @CharVal = REPLACE(@CharVal, '[205]', '[Í]')
            --SET @CharVal = REPLACE(@CharVal, '[206]', '[Î]')
            --SET @CharVal = REPLACE(@CharVal, '[207]', '[Ï]')
            --SET @CharVal = REPLACE(@CharVal, '[208]', '[Ð]')
            --SET @CharVal = REPLACE(@CharVal, '[209]', '[Ñ]')
            --SET @CharVal = REPLACE(@CharVal, '[210]', '[Ò]')
            --SET @CharVal = REPLACE(@CharVal, '[211]', '[Ó]')
            --SET @CharVal = REPLACE(@CharVal, '[212]', '[Ô]')
            --SET @CharVal = REPLACE(@CharVal, '[213]', '[Õ]')
            --SET @CharVal = REPLACE(@CharVal, '[214]', '[Ö]')
            --SET @CharVal = REPLACE(@CharVal, '[215]', '[×]')
            --SET @CharVal = REPLACE(@CharVal, '[216]', '[Ø]')
            --SET @CharVal = REPLACE(@CharVal, '[217]', '[Ù]')
            --SET @CharVal = REPLACE(@CharVal, '[218]', '[Ú]')
            --SET @CharVal = REPLACE(@CharVal, '[219]', '[Û]')
            --SET @CharVal = REPLACE(@CharVal, '[220]', '[Ü]')
            --SET @CharVal = REPLACE(@CharVal, '[221]', '[Ý]')
            --SET @CharVal = REPLACE(@CharVal, '[222]', '[Þ]')
            --SET @CharVal = REPLACE(@CharVal, '[223]', '[ß]')
            --SET @CharVal = REPLACE(@CharVal, '[224]', '[à]')
            --SET @CharVal = REPLACE(@CharVal, '[225]', '[á]')
            --SET @CharVal = REPLACE(@CharVal, '[226]', '[â]')
            --SET @CharVal = REPLACE(@CharVal, '[227]', '[ã]')
            --SET @CharVal = REPLACE(@CharVal, '[228]', '[ä]')
            --SET @CharVal = REPLACE(@CharVal, '[229]', '[å]')
            --SET @CharVal = REPLACE(@CharVal, '[230]', '[æ]')
            --SET @CharVal = REPLACE(@CharVal, '[231]', '[ç]')
            --SET @CharVal = REPLACE(@CharVal, '[232]', '[è]')
            --SET @CharVal = REPLACE(@CharVal, '[233]', '[é]')
            --SET @CharVal = REPLACE(@CharVal, '[234]', '[ê]')
            --SET @CharVal = REPLACE(@CharVal, '[235]', '[ë]')
            --SET @CharVal = REPLACE(@CharVal, '[236]', '[ì]')
            --SET @CharVal = REPLACE(@CharVal, '[237]', '[í]')
            --SET @CharVal = REPLACE(@CharVal, '[238]', '[î]')
            --SET @CharVal = REPLACE(@CharVal, '[239]', '[ï]')
            --SET @CharVal = REPLACE(@CharVal, '[240]', '[ð]')
            --SET @CharVal = REPLACE(@CharVal, '[241]', '[ñ]')
            --SET @CharVal = REPLACE(@CharVal, '[242]', '[ò]')
            --SET @CharVal = REPLACE(@CharVal, '[243]', '[ó]')
            --SET @CharVal = REPLACE(@CharVal, '[244]', '[ô]')
            --SET @CharVal = REPLACE(@CharVal, '[245]', '[õ]')
            --SET @CharVal = REPLACE(@CharVal, '[246]', '[ö]')
            --SET @CharVal = REPLACE(@CharVal, '[247]', '[÷]')
            --SET @CharVal = REPLACE(@CharVal, '[248]', '[ø]')
            --SET @CharVal = REPLACE(@CharVal, '[249]', '[ù]')
            --SET @CharVal = REPLACE(@CharVal, '[250]', '[ú]')
            --SET @CharVal = REPLACE(@CharVal, '[251]', '[û]')
            --SET @CharVal = REPLACE(@CharVal, '[252]', '[ü]')
            --SET @CharVal = REPLACE(@CharVal, '[253]', '[ý]')
            --SET @CharVal = REPLACE(@CharVal, '[254]', '[þ]')
            --SET @CharVal = REPLACE(@CharVal, '[255]', '[ÿ]')
        END
    ELSE
        BEGIN
            SET @CharVal = SUBSTRING(@SearchString, @CharPosition, 1)
        END

    SET @ReturnVal = @ReturnVal + @CharVal

    SET @CharPosition = @CharPosition + 1
    END

IF (@isValid = 1) SET @ReturnVal = NULL

RETURN @ReturnVal

END

And then, call it like:

SELECT BadString, dbo.Find_Invalid_Chars(BadString) [Invalid Characters]
FROM #tmp_Table tmp_mc
WHERE dbo.Find_Invalid_Chars(BadString) IS NOT NULL

Sample Output:

With Char Identity

Or

Without Char Identity