Could not find any good answers to this and since I did it on my own I'd like to share how:
Talk to the Power Armor repair guy on level 3 in the very back on the far right. He will tell you several ways to get the Systolic Motivator which will allow him to repair the Power Armor sitting on his table.
Steal it from Rhombus: Go to the first floor. Rhombus is the first room just below you after you enter. His room has two parts. In the second part is a locker. He will be standing in that room in the back next to his bed. If he is back by the bed then enter the first room otherwise use the PIP-boy to wait until morning. This should make him go back there.
NOTE: For those who do not know how to use the PIP-boy. Click on the PIP icon in the lower right of your screen. It is very tiny. On the PIP screen click on the yellow colored bell at the top of your screen that is built into the current time/date. To the right will be a list of different times you can wait.
Now...go stand against the second door. Do NOT enter the second room. Click the door to open it and then run to the right (still in the first room) by about 4 steps. Rhombus will say 'Who is there?' and start walking your way. The door will close. Rhombus will re-open it and step into the first room. This is your chance. When he opens the door click to move you character into the next room over by the locker. You will run right by him and he won't see you. You DO NOT have to use the SNEAK skill at all during this mission. Period.
Take the Motivator from the locker. To get Rhombus to come back you must do two things.
1) Stand to the left of the locker and face towards the locker and away from the door. This is critical. 2) Use the PIP-boy to wait until it is Midnight.
Rhombus will detect it is midnight and want to go to bed. Don't move or even breath . :-) He will walk right by you and not see you. When he gets back to his bed run for it. Open the second door and step into the first room.
You can do one of two things now. I did the following: 1) Walk to the right of the first room and don't move. Rhombus will not come into the first area. When he just stands there and the second door is closed. Go for it. Run out of the first room. Victory! 2) Just go for it. Run through both doors. I don't know if Rhombus will catch you or not if you try this but I really don't think he will.
Repairing the Armor: You will need a repair skill greater than 40%. I know...I had a 40% skill level and could not do it. Go to the HUB , next to the general store is the library. Buy Deans Electronics books and read them until you get your repair skill high. I had lots of money and took myself to 75%. Yes, the books are expensive but at this point in the game you should have lots of money and goods to trade. Talus, back in the brotherhood, will give you all kinds of free armor/ammo which you can trade at this point. He is on level 1 to the right/bottom in the workout training room. Went back and the repair on the armor on the table worked.