[Avodah] HaMelech Hakadosh

[cantorwolberg at cox.net]

 I have been unable to find a source to either confirm or contradict this. Does anyone know of a source which speaks of this situation, i.e., if one says "HaMelech Hakadosh" at a time OTHER than the Aseres Ymei Teshuva?

To me it would be obvious that it is invalid since it is the converse of the halacha.
Therefore, I see no reason why there has to be an additional source.
In other words, if 'hamelech hakadosh is specific for the aseres y'mei t'shuva and
doing the usual 'hakel hakadosh' instead would render it invalid, then the converse
would also be true. If it were not so, and doing the 'Hamelech hakadosh' after the
aseres y'mei t'shuva didn't invalidate the tefilla, then the hamelech hakadosh 
during the ten days, would lose its essence.