One of my latest customer Mr. Jorge from Belize send an email to me with an issue which he wanted me to explain a little, let hear what he is saying.
Hello Mr. Humphrey,
Please just one question on the CRT course that I am not sure about.
1. I reached chapter 9 “on how to find a shorted components using series bulb on the primary power supply fast!”… Where it says you remove a pin of some components. When I do this, do I re-solder back a component if it is ok and go to another or do I leave the pin out and go take out the pin of another?
Humphrey: The reason I introduced this method is to assist technicians to be able to catch those hard to find components which present a short under load and if there is no load the meter will not detect them.
Please note that the component which present short (bulb lights with high intensity) are component placed in parallel with the power line (by this I mean one pin is touching on the power line and the other leg on the ground. Good examples are the components I have highlighted on chapter 9 of your book. So if any of those components present a short it is like you have placed a jumper wire between the live and ground and hence short circuit.
Now coming to your question I will say you are right(just lift up only one leg of the component) with the power off and equipment disconnected from the outlet , apply power again via series bulb and if the bulb is still bright then it means that component is ok and should be re-soldered back and continue with the rest.
2. Also is there a possibility that a component will blow up by doing this?
Humphrey: When you dis-connect one leg of a component placed in parallel it means that component is now open circuit….open circuit does not make any harm to the circuit…the greatest harm is done by a short circuit and this is the biggest killer of electronics equipment.
A word of advice though is when you are troubleshooting the secondary side of the power supply and decide to dis-connect the B+ load ,it is always advisable to use a dummy load on the B+ line, if not the B+ voltage may increase a lot and blow some capacitors a long that line. See details of making one in Chapter 4 of your book.
All the best Jorge