Almost 30 years old. Old good times without BGAs and modern barely visible components. While some basics are still applicable the modern problems are not covered at all.
Provided you have good eyesight and steady hands, I've mostly found what happens as you get smaller is:
- Heating becomes easier. There's no large sinks to take the heat away. It's also easier to overheat things.
- You need finer tweezers, and don't drop them because if you do the tips will bend.
- The solder's surface tension does more of the work. It feels a lot more like sticking together things with tiny droplets of glue. Having the correct amount of solder in the right place is critical.
- Solder and flux become two separate things you have to care about individually
- It is easier to burn yourself
- learning how to brace your hand against something in a way that gives you very fine control. One reason soldering with an iron can be difficult is because your hand is so far away from the tip, like trying to write with a pen held by the end.
I don't think that modern boards are really repairable at all beyond component replacement- 4+ layer stackups being the big reason. If there's a way to do anything to those boards besides total replacement I'd be super interested to know.
The techniques here are also way beyond basics I think- like, you look at most guides for repair and it's "idk just solder some bodge wires on there, here's what a good joint should look like"
If it's QFN, you're probably best deadbugging it and jumpering all of the pins individually, but first make sure that you need the connection. QFP wireframes all have a center pad, whether or not it's electrically connected to the die or needed for thermal dissipation.
If it's an SO package, e.g. SSOP, TSOP, etc., Desolder the IC, add the jumper wire, bend the pins down enough to account for the thickness of the jumper wire, and resolder the IC.
Either way, make sure you have enough thermal mass connected to it for thermal dissipation. If there's components on the opposite side of the PCB, it's probably not much.
> Destructive static charges are induced on nearby conductors, such as
human skin, and delivered in the form of sparks passing between
conductors, such as when the surface of printed board assembly is
touched by a person having a static charge potential. [..] It is important to note that usually the static damage level for components cannot be felt by humans. (Less than 3,000 volts.)
Less than 3000 volts cannot be felt by humans? Should be 3000 millivolts right? i.e. 3 volts...
It's 3000V, but the energy delivered can be absolutely minute on a human scale, even for the highly sensitive nervous system. But metal oxide layers (what static discharge is often blowing holes in) are not on a human scale, they're atoms thick. And highly insulating, which leads to teravolts/metre field gradients.
For discharge that you can feel and see, the energy is even higher, but damage can be done far below this level.
Considering static discharge is a spark, I assume 3.000 volts is the correct scale. When I wince from a static discharge generally there's visible spark.
SATA ports are often rated for only tens to hundreds of cycles, so they're often made out of fallapartium.
If you're replacing one, it's easiest to cut all of the plastic off first, then desolder the contacts one at a time. Sometimes you can even pull the plastic off, without damaging it. It's usually necessary to preheat the board.
Things like that are often the only through-hole components on a PCB.
I like to melt the original solder one contact or area at a time, add a little bit of fresh flux-containing solder if needed, and as soon as it gets to the consistency of mercury, vacuum it clean out with a good soldersucker.
lnsru|13 days ago
alnwlsn|13 days ago
- Heating becomes easier. There's no large sinks to take the heat away. It's also easier to overheat things.
- You need finer tweezers, and don't drop them because if you do the tips will bend.
- The solder's surface tension does more of the work. It feels a lot more like sticking together things with tiny droplets of glue. Having the correct amount of solder in the right place is critical.
- Solder and flux become two separate things you have to care about individually
- It is easier to burn yourself
- learning how to brace your hand against something in a way that gives you very fine control. One reason soldering with an iron can be difficult is because your hand is so far away from the tip, like trying to write with a pen held by the end.
Vexs|13 days ago
The techniques here are also way beyond basics I think- like, you look at most guides for repair and it's "idk just solder some bodge wires on there, here's what a good joint should look like"
varjag|13 days ago
nxobject|13 days ago
amelius|13 days ago
dlcarrier|13 days ago
If it's an SO package, e.g. SSOP, TSOP, etc., Desolder the IC, add the jumper wire, bend the pins down enough to account for the thickness of the jumper wire, and resolder the IC.
Either way, make sure you have enough thermal mass connected to it for thermal dissipation. If there's components on the opposite side of the PCB, it's probably not much.
eimrine|13 days ago
emporas|12 days ago
Less than 3000 volts cannot be felt by humans? Should be 3000 millivolts right? i.e. 3 volts...
georgefrowny|12 days ago
For discharge that you can feel and see, the energy is even higher, but damage can be done far below this level.
bayindirh|12 days ago
That's not 3 volts.
eimrine|13 days ago
dlcarrier|13 days ago
If you're replacing one, it's easiest to cut all of the plastic off first, then desolder the contacts one at a time. Sometimes you can even pull the plastic off, without damaging it. It's usually necessary to preheat the board.
fuzzfactor|13 days ago
I like to melt the original solder one contact or area at a time, add a little bit of fresh flux-containing solder if needed, and as soon as it gets to the consistency of mercury, vacuum it clean out with a good soldersucker.
donquichotte|13 days ago
barfiure|13 days ago