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Full Recap or Partial ??

Califmike33 said:
Got another sa 300 on the way going to use the body of my current one but use the boards on the other one and do the recap going to keep practicing and practice and practicing to my soldering gets decent before I attempt to recap the one that's coming.
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Good plan!

Also, no harm in nosing around in the service manual in the meantime. Spend some time with the schematic and board diagrams and start to get a feel for what all those symbols represent and how the components interact with each other in circuit.
 
Still waiting for my other SA 300 to arrive, have been practicing soldering and reading up on electronics. Cant wait for item to arrive so i can begin recap.
 
Hey guys want to know how you work, do you remove pcb from case and work on it ? . Im stuggling with frying tracers, the solder i think is coming along pretty decent. Im not confident i can pull this off, is alot of parts to replace.
 
If you're damaging traces (note: traces, not tracers) your technique and/or tools and supplies still need to be improved before thinking of working on something you care about. You should be very comfortable with desoldering and soldering before proceeding. Don't be in a hurry! Spend some time improving your skills.

I leave boards in place if I have good access to the solder side and can get to components to remove/replace them. I'll move or remove them if I have to, but any movement can risk damage to connections or the boards themselves.

I use a desoldering gun for desoldering unless the location is inaccessible with the gun. In that case I'll use solder wick. For soldering I use a temperature controlled station and eutectic solder - fine enough that it feeds easily and cleanly into small solder joints, rather than globbing on. Finally, while both desoldering and soldering, I use magnification and work under a bright light. It makes doing clean work so much easier.
 
Ok heres what im doing, unsoldering one side pulling it in, unsolder otherside pulling it in until cap comes out. I then take wick and clean up solder on board so i can clearly see holes to put new cap. I think sometimes i over heat it, need to be more careful overheating. Im not pushing cap out towards solder or wiggling at all. Maybe i will turn down the heat on gun, its adjustable. Maybe look into desolder gun too. I bought a desktop magnifier with light so that helps.
 
Califmike33 said:
Ok heres what im doing, unsoldering one side pulling it in, unsolder otherside pulling it in until cap comes out. I then take wick and clean up solder on board so i can clearly see holes to put new cap. I think sometimes i over heat it, need to be more careful overheating. Im not pushing cap out towards solder or wiggling at all. Maybe i will turn down the heat on gun, its adjustable. Maybe look into desolder gun too. I bought a desktop magnifier with light so that helps.
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What are you using to remove the solder prior to removing each cap? (You said you use wick after the cap's out.)
 
A desoldering gun does make the task easier, just depends on if you think you'll do this sort of work enough to justify the cost. Of course, you could always sell it if you don't continue to do this work and recoup much of the investment. One other trick for now though, add a bit of fresh solder to the joint BEFORE desoldering. Makes the old solder flow more easily for wicking.
 
Well I'm heating up both spots of solder and pulling the cap out and then cleaning up with wick. Or should I be using the wick to heat up the solder and then pull the cap out doesn't matter?

I just heat up one side pull it inwards towards me heat up the other side pull it towards me until it just comes out but I'm not pushing on it so it destroys or wiggling it the trace.
 
That IS. a valid way to do it, but you'll find that many times the leads are bent tight to the board, especially with resistors. Try the added fresh solder and see if that helps. You're only adding a tiny bit of fresh, but the new flux and solder mix with the old and let it flow better afterwards.

Edit: Also, be careful when you use your method as the force pulling the one leg out is exerted on the other leg a little, pushing it IN. This can sometimes cause pads to lift. If the cap was very tight to the board, that doesn't happen quite so often.
 
Well I'm actually not removing one leg first and then the other one I'm sort of inching them both along one at a time until one will eventually pop out but the other ones 90% of the way out.

I will try adding some solder before I desolder.
 
Califmike33 said:
Well I'm actually not removing one leg first and then the other one I'm sort of inching them both along one at a time until one will eventually pop out but the other ones 90% of the way out.

I will try adding some solder before I desolder.
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This may be why traces are failing. In order to keep a pool of solder molten while you attempt to pull the component's lead free, you need to continue to apply heat. Far better to remove the solder quickly and completely and then remove the component. A manual solder sucker is a very inexpensive tool. They're nowhere as convenient or easy to use as a desoldering gun, but you can use one to quickly remove the bulk of the solder. If a small bit remains, still retaining the lead, you can follow up with wick.

Adding solder is a valid way to desolder otherwise stubborn connections, but I've never found it necessary for the majority of the work I've done. Plated through-holes are the one place it's been commonly necessary. Otherwise, quickly applied heat combined with suction almost always gets the job done. (I've even had good success with a rubber bulb-type solder extractor, when nothing else was available.)

Here's a video on desoldering. It's old (bear with that) and a desoldering gun is used, but you can take tips on manual desoldering from it. Note how little time heat is applied and that the solder is removed before attempting to remove the component. The same is good practice for manual work.
 
Well I'll tell you what after watching that video I want a desolder gun that sucks it up all in one gun can somebody recommend me a good one that's not too expensive?
 
In the mean time, try just putting the desoldering wick on top of the solder joint (ideally with a little flux), and the iron on top of the wick - as soon as the solder melts it'll 'suck' itself into the wick. It also acts a bit like a heat sink, so you're not overheating the joint too much.
I remove all the solder, so the leads are 'loose', before attempting to move the cap, using either just desoldering wick if it's a small joint, or a solder sucker then wick, if it's a larger joint.
 
Yeah I've tried a solder sucker that you hold in your hand and I don't like it but the wick works good I'm going to try it tonight with just getting the wick heat it up and sucking the solder up and try to remove the capacitor that way.

Looking at the desolder guns that have built-in vacuums the cheapest decent when I can find about $250 don't want to spend that much money yet.
 
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So if you guys are working on a vintage receiver for example do you remove the PCB out of the case and work on it or do you leave it inside the case and work on it?
 
Think im in the school of min disassemble, my amp is pretty easy to get to most stuff. Well was practicing tonight desoldering, using wick, and im going with a desolder gun i found on amazon with some pretty good reviews. I think it will save me loads of time and possiable damage to the board, its $129, i do plan on doing this as a hobby so there will be other amps to work on.
 
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