Change stars as read-hide-char

[Colin Baxter]

My apologies for posting here, I can't get posting rights at
gmane.emacs.help. My `return-confirmation' emails get bounced at that
news-group. 

The development emacs-27 version recently changed the default character
seen when entering a password from `.' to `*'. I want to get back to the
old default, but

(let (read-hide-char) "?.")

does not work, and my e-lisp knowledge is insufficient to understand the
reason. What am I doing wrong?

Thanks.

Colin.