Siteuser,
I took the tech exam a couple months back and passed it.
The review exams are definitely helpful; make sure you time yourself when you do the exam and work as fast but as efficient as possible. The tech exams are in the same format as the practice exam.
For example, measurements and graphs are the first part; second part is diagrams counting things using a legend; third part was mechanical pictures; fourth was rules of reasoning.
Also for the mechanical part of the exam I suggest getting a asvab book and study pulleys setups, circuits and anything else in the book. You can find them at the library or book store.
I believe just knowing the format of the exam and pace of the exam is the key to doing well.
I kept doing the practice one over and over to get my pace down.
My first part of the exam was just simple addition and subractions using measurements provided of an object.
Then addition and subtraction of line graphs for the other part.
Rules of reasoning there was a circuit diagram but different from the practice one; also just a reading part with rules.
I start my new job tomorrow!!!!
Good Luck
