unmatched query problem

[beginner33]

Hi!
I am total amateur with MS Access VBA and I have a problem with a sort of "unmatched query". I would like to ask someone for help. At the moment I have no solution that works at all. If my current approach would work at all, it would be very complicated. I am sure there is better way to do it...

Basically I have two tables; first one is a "LIST OF ALL EQUIPMENT". Among all other columns it has "INVENTORY NUMBER" which is the link to second table.
Second table is a "LIST OF ALL SERVICE CASES" which contains data about repairs, etc. This table also has a column "INVENTORY NUMBER" (which can be used to link both tables) and a column "SERVICE CASE CLOSED DATE". The table contains data for longer period, let say 10 years. Some of equipment has for example one case per month, other equipment units have no registered service cases at all, and those units I want to track. Multiple cases are probably the problem that "unmatched query" wizard doesn't produce what I want….
My goal is to produce third query which would contain number of equipment that has never ever been serviced, arranged by quarters and for current year only. In other words, list of equipment that has no record in second table (before the quarter ends). Actually I need only 4 numbers in my final query, for example:

2016_Jan_Mar: 120 Pcs (count of equipment units, that has no service case registered, before April 1th)
2016_Apr_Jun: 110 Pcs (count of equipment units, that has no service case registered, before July 1th)


2016_Jul_Sep: 100 Pcs (count of equipment units, that has no service case registered, before October 1th)
2016_Oct_Dec: 90 Pcs (count of equipment units, that has no service case registered, before January 1th, 2017)

Thank in advance for your help!

[orange]

Show us the table designs ---fields in each table. And the SQL for your query.