If the lead is too large in the hole it will be a real bear to remove. Once out on difficult holes to clear I'll heat from one side and use the solder sucker from the other. Large ground plance are the biggest challenge and where this technoque is essential. I use solder as a heat conductor to get the solder in the hole to melt. no suction until its all melted.
replacing components that are good is bad practice. Electrolytic caps have the shortest lifespan but I have some 50 year old instruments with original caps that check out fine on ESR etc. Heat is the enemy so caps near heat sinks or in equipment that runs hot will fail sooner. otherwise you are more likely to make problems replacing good parts. This holds for pulling tubee to test if the unit is working.
ya i know but i had 2 of the 3 amps that needed to be fully taken apart 1 needed new main caps and the other needed new speaker terminals and had one cap not looking very happy and was under rated compared to the other channel so i thought i might as well do the hole lot.
according the the service manual there meant to be 56pf and the grey one is 33 so i need to change that. also what type cap is that?
i couldn't compare with the 3rd amp as it was an earlier revision and the pcb is completely different using a glass looking cap?
A couple tips from my experience:
- If you have an electric oven, prewarm the PCB to 40° C (~150° F). This reduces the heat difference between the PCB and the iron so it doesn't have to 'work' as hard to reach melt temp. Recommend gloves for handling the warm board.
- Use a 2nd soldering iron on the other side of the PCB.
- If you are certain you know the diameter of the plated-thru hole, a last resort is to drill the via with a pin vice and drill bit at least 20/1000ths inch (0.5 mm) smaller than the hole diameter. This is dicey sometimes on a board with internal layers, due to the risk of wiping out the connection of the via to internal layers.
Can be. I clear as much as I can using braid and that often leaves a concave plug in the hole. Let it guide the smallest drill then widen to one that's just large enough for the replacement component.
Search for Microbox to get started. Some sets have drills as small as 0.3mm