Try By assigning MinuteIncrement="1"
HTML
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<style type="text/css">
span
{
font-family: Arial;
font-size: 10pt;
font-weight: bold;
text-decoration: underline;
}
</style>
</head>
<body>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<span>Default Mode</span><br />
<br />
<cc1:TimeSelector ID="TimeSelector1" runat="server" MinuteIncrement="1">
</cc1:TimeSelector>
<hr />
<span>Set Specific time</span><br />
<br />
<cc1:TimeSelector ID="TimeSelector2" runat="server" Hour="12" AllowSecondEditing="true"
AmPm="AM" MinuteIncrement="1" Second="10">
</cc1:TimeSelector>
<hr />
<span>Clock Mode</span><br />
<br />
<cc1:TimeSelector ID="TimeSelector3" runat="server" EnableClock="true">
</cc1:TimeSelector>
<hr />
<span>ReadOnly Mode</span><br />
<br />
<cc1:TimeSelector ID="TimeSelector4" runat="server" ReadOnly="true">
</cc1:TimeSelector>
<hr />
<span>Remove Seconds from the Time</span><br />
<br />
<cc1:TimeSelector ID="TimeSelector5" runat="server" DisplaySeconds="false" MinuteIncrement="1">
</cc1:TimeSelector>
<hr />
<span>Hide Buttons</span><br />
<br />
<cc1:TimeSelector ID="TimeSelector6" runat="server" DisplayButtons="false">
</cc1:TimeSelector>
<hr />
<span>Twenty Four Hour Format</span><br />
<br />
<cc1:TimeSelector ID="TimeSelector7" runat="server" SelectedTimeFormat="TwentyFour"
MinuteIncrement="1">
</cc1:TimeSelector>
<hr />
<span>Allow Editing of Seconds</span><br />
<br />
<cc1:TimeSelector ID="TimeSelector10" runat="server" AllowSecondEditing="true">
</cc1:TimeSelector>
<hr />
<span>Set Time from Server side</span><br />
<br />
<cc1:TimeSelector ID="TimeSelector9" runat="server">
</cc1:TimeSelector>
<hr />
<span>PostBack Time Example</span><br />
<br />
<cc1:TimeSelector ID="TimeSelector8" runat="server" AllowSecondEditing="true">
</cc1:TimeSelector>
<br />
<asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClick="Submit" />
</form>
</body>
</html>
C# and VB.Net Code same as Article code
Screenshot
