I have actually gone to school to become an electronics tech. My 2nd week of school we were in a lab and had a small circuit set up but one of the students was having problems with his signal generator. The prof was SUPER fat and rarely got up out of the desk so he was helping the student troubleshoot the generator as he sat at his desk. "Is this switch on? Is this set to output - A? Is it plugged into output - A?" and then finally started to slowly get up from his desk when I heard the student having issues start to "tap" on the generator before announcing "HEY fixed it!". My prof suddenly got up rather quickly from the desk and demanded that we all pay attention. I figured he was going to start bitching about beating/smacking the schools equipment so you can imagine my surprise when he started to tell us that he didn't hit it, he didn't smack it, and he didn't beat on it THAT is called a technical tap and you can trouble shoot and diagnose a LOT of electrical problem with it, fix a few things with it but as a tech you get to bill for it.... That was over 20 yrs ago and he was right as I have used it in my audio area as well as when I was working for intel on million dollar production equipment. Truth is he didn't make it up as it goes all the way back to the start of electronics and vacuum tubes. The old tubes(that were replaced by transistors) stood up in a clip like harness that made the connections at the bottom. They were not able to manf then as accurately as then can today and after a while when the tubes heated up they could expand and loose contact to the pins so it was not uncommon at all that on what was the latest technology of the time that they would have to go and tap on the top of the tubes and they would again make contact and work.
STart lightly with your finger tips, move up to you 1rst knuckle, then go to your 2nd knuckle, Then Go to a light tapping with your fist, then start throwing mad hammer fists before you get a hammer and beat the FFFFFf out of it.
