None of those pops should play that particular sound.
IIRC, that's the game startup sound.

With the game turned off, reseat the connector on the sound board several times.
Do the same for the connector(s) on the left side of the driver board.
Retest.

Let us know.

It's tough to say much more since you have a Pascal board in it.
I'd like to hear from other folks who are running the Pascal board in HH to see if they have the same issue.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

You can compare the sounds you're getting with various YouTube vids.
Sound is pretty simple with HH although the sound board itself is a bit of a nightmare.
The MPU can command 31 separate sounds via a 5 bit pattern.
If one of the bits is missing from the interface, the wrong sound would play. You'd notice more incorrect sounds than you might have.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

You can check with John's Jukes over in Vancouver if you want to keep it in Canada.
Or you can send it to me for checkout/repair.
Drop me a PM if you want to send it to me in St. Louis, Missouri.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info