Data model doesnt work when adding a 3rd relationship

[Anonymous]

I am creating a relationship between my main fact table HW Inventory and 3 other tables.  All of the tables have a serial numbers I am making the relationship on.  Here is the model that *Should* work.  When I add a field from HW Inventory and Battery, Exported Cycles or Software bothe Serial numbers show up.  If HW Inventory any one of those dimension tables is selected both show the correct serial BUT any 3rd dimension table is selected I get the error PBI cant determine the relationship between two or more fields.  Now the kicker is the next model

The only way I can get all 4 serial numbers on the visual from each table without an error is using this model pretty much running it through one of my other dimension tables.  This just feels wrong.   How can I debug why the first model that I believe is correct wont work? or someone correct me if I am wrong that it should work as I expected.

[lbendlin]

Ask yourself which of your tables are fact tables and which are dimension tables. Try not to join fact tables directly. Instead, have all your fact tables controlled by the dimension tables.