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Issue with SA-7800

Hey guys just a quick update sorry ive gone a bit silent but dealing with work and family stuff.

My question is, you all know im a noob at this and havent Desoldered/solderes before. I did pick up a decent Weller solder and even a little sucker for the Desolder with some sort of brass attachment which i belive the warm soldier attaches itself too? Anyway, i just don't want to do more harm then good... is this the root of the issue? Also, when i do this, how would you recommend i secure the chassis...i mean, do i hold it upright and hold onto the component so it doesnt fall and possibly break after the desoldier or do i simply put it on its solder side up and concentrate on that area and not worry about the component drop.

Any tips or videos you can share on how to properly do this is much appreciated!
 
I went through the same curve. Get something broken, maybe at goodwill, and practice on that. It will give you the needed practice and confidence to do the job.
 
loweran said:
I went through the same curve. Get something broken, maybe at goodwill, and practice on that. It will give you the needed practice and confidence to do the job.
Click to expand...
Ironically enough, this was a salvation army find. Got the amp & tuner for $30 altogether
 
They might have been cheap but they are worth MUCH more, as I'm sure you know, so take care.

I have been in the hobby for about two years now and when I started out, anything that needed component level repair, I passed on because I didn't know what to do or how to solder. Like anything else, your approach is key.

My general advice would be - don't go too hot. I used to use a huge old iron that could solder the Titanic. Bad idea - I burned components and lifted traces all over the place. I now use a simple little 40 watt iron with a pencil tip and built in light - works great.

I also use a solder sucker, or pump, as personally I didnt get on with braid / wick.

Get a metallic sponge to clean the iron tip - a clean tip is king. Also I find extra Flux added to the work helps solder flow.

When desoldering, I usually work with solder- side upwards. Don't worry about things falling when loose, they are tiny and weigh next to nothing, no damage will occur. Real damage will occur by applying too much heat so practise on some junk as advised above - really do this, we are not trying to add more hurdles for you :-)

If a component won't come off the board with finger pulling once desoldering, don't use pliers. I haVE done that a pulled off traces from the Board. Go back and desolder more.
 
For a transistor reflow like we are talking here, don't remove all the solder at once. Do one leg at a time because if it falls out you will need to ensure you have it the right way round when you put it back in. Don't make extra work for yourself.
 
Make sure work area is clean, well lit and lay off the beer / caffeine as a steady hand tm really helps :) Use magnification like a cheap pair of those reading glasses, really helps too.
 
Thanks for all the great advice Mark. Really helpful stuff. One question about the extra flux...i did an extra tube of it on advice from someone else. Now after it is Desoldered..at that point would you put flux on FIRST *before* the reflow? Or would you reflow first and then add the flux on top?
 
What Pete said ^

I also tend to use a little dab on the joint prior to heating the solder as the flux helps to clean away oxidisation and gunk from the joint (or at least that's my understanding). So to answer your question, if using additional flux, it goes on first followed by heat and solder.
 
I would recommend watching some tutorials on YouTube for soldering. One of the biggest mistakes I made, other than excess heat, was thinking that I had to heat the solder rather than the work. If you heat the solder, it just balls up and drips all over. If you heat the piece you are working on (pad / pin) and then feed the solder in you will get a much easier and neater job.

Rather than clutter up this quite technical repair thread, you are very welcome to PM me for beginner to beginner advice. That way we can keep this thread on track for the repair and I can pass on some tips via messages for you.
 
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