Have you ever had a problem with your central vacuum where it intermitently loses suction power or even powers down and then starts again?
I did. The problem was especially pronunced when holding the hose a certain way (i.e., bending it that way or stretching the hose a bit). The first time it happened, I had owned the vacuum for a little bit more than a year so I brought it into the shop thinking it would be a warrantied fix. Wrong, the vacuum company told me it was a "maintenance" item and would not reimburse me (despiste me sending them a letter asking so). I was out almost 100$ for having the contacts cleaned on the hose (the inside contacts near the switch on the handle)!
A few weeks ago, after 3 years without problems, the same thing started happening. I put my DIY hat on and figured that the worst I could do was to fail at repairing it and having to go to the repairman (i.e., same situation as now).
I unscrewed 6 screws on the handle and promptly cleaned the 4 contacts and their respective brass rings using 99% isopropyl alcool and Q-tips. The whole ordeal took maybe 20 minutes from start to finish. Now it works like new and I made the equivalent of 300$ an hour post tax!
Don't be afraid my friends! Open it and see how it works inside (make sure to unplug it first!).