Note that ‘\Let@’ stands for ‘\let\\=\cr\’, and so it should be placed after the definition of ‘\cr’ is recalled in halign tables.
<..amstex loads amsmath..>
\input amsmath.4ht
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<..amstex1.4ht..>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% amstex1.4ht 2014-07-12-22:36 %
% Copyright (C) 1997--2009 Eitan M. Gurari %
<.TeX4ht copyright.>
% amstex.sty
\if@compatibility \else
<.amstex loads amsmath.>
\expandafter\endinput
\fi
\let\ltx@label=\lb:l
<.body of amstex.sty.>
<.equations of amstex.sty.>
<.label of amstex.sty.>
<.amsmath.sty and amstex.sty.>
<.config amstex1 utilities.>
<.config amstex1 shared.>
<.plain, fontmath, amstex.>
\Hinput{amstex1}
\endinput
-_-_-