finding bad solder joints

[timmy]

i dont recall seeing anything about finding bad solder joints aside from just looking, but for the possible newbie wanting to know the best way or the easy to find these hidden problems this may help. this is to do with 40+ year old tvs or maybe anything with tubes, what i learned is that anything that sits high on the circuit board like caps,resistors or maybe a choke that is near or just around a tube will for sure be a bad joint even though the solder looks good just put one finger on the component solder side and the other side rock the component from side to side and you will feel it move then solder it. i say this because if you think how many times a tech was in the set changing tubes over a 40-50 year time frame well then reaching in for this work its hard to avoid bumping into the high sitting components.im sure many of you guys out there have also bumped into things to get a tube out.so if you were to take lets say a cap and rock it a few times in these old sets then you know it will have to be soldered again because it dont take much to break the solder bond.just alittle helpful hint for some if it would help.

[marty59]

I would also recommend a pair of magnifier/readers with the headband. I wouldn't wiggle parts around just for the heck of it as you could also induce problems so keep that in mind.

However, if you believe something is questionable in an area you may not notice it with the naked eye. Put the magnifiers on and confirm those connections while moving the suspect component and observe its connection.

[reeferman]

Back in the old days if the set was working we would just tap the circuit board with the butt end of a 1/4" nut driver (making sure there wasn't anything with long leads on it). Worked quite well. For items like power resistors or around items where the PCB is heat discolored at the joint just re-solder them...but...it is not uncommon to have to remove the component first to clean up the leads. Then reinstall component and solder to the board. If you apply too much heat to a dirty lead and PCB at the same time the PCB copper trace always loses. Take your time, hone your soldering skills, and have fun.
Phil