I googled Hillquist Excavating and was able to get in contact with Ron Hillquist of Geneva IL. Ron and his brother Terry were owners of the company. I told him about the 15-B and asked if he would happen to have any photos of it from back in the day. He did not but told me the Geneva historical society might have something. I next reached out to the historical society and they were able to locate a photo of a Hillquist 15-B working. Its not this exact machine but still a neat piece of history. 
 
 

 The boom hoist - it is a clutch within another clutch - in almost every 15B is possessed by Satan. It will pull the "A" frame back into the cab and bend the "A" frame legs (just like yours).
Always remember the main clutch.

With that handle, you should be able to get 15' deep right in front of the house.

Attached is a picture of my 15B from a few years ago.

 

That looks like a very nice machine! Thanks for posting.