"\" is special in string literals. You need to escape it.

$server = "SERVER05\\LDEV";  # Produces SERVER05\LDEV
$server = 'SERVER05\\LDEV';  # Produces SERVER05\LDEV
$server = 'SERVER05\LDEV';   # Produces SERVER05\LDEV
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The third works since "\" only needs to be escaped when it's followed by another "\" or the string delimiter (') in single quoted strings.