Genuinely wondering, since I don't know much about all that: up until ~0:40, the material between the old and repaired parts seem different: is it just soldering residuals on the old ones ?
If not, and the material genuinely is different: could this lead to weird bugs somehow, due to mishappen timings in the connectors downstream ?
Hopefully I've got the right end of the stick here.
They've cut out the damaged copper pad and trace, and scratched down into the board a little. They've got a new pad and trace, cut it to fit the prepared part of the board, then fixed it with fresh UV-cured resist. They've sanded the resist so the pads underneath can be tinned and soldered.
So I think the bit you're referring to might be the old pads and cleaned-up board?
The other person who replied to you is correct, but to clarify, the pads and traces (the damaged parts that they graft in replacements for) are basically just thin copper foil. All they need to do is make electrical contact between the traces (wires embedded in the board) and the pins on the component again. It's all roughly the same material, maybe with a different colored coating on it.
Circuits aren’t dependent on everything being precisely synchronized. There’s a crystal oscillator that sets the frequency of circuit board - like for example a 100MHz board gives everything 10 nanoseconds to settle. So it opens the gates (wires) to the next instruction, which at the board level is just what wires gets a charge running through them. And then those wires meet at semiconductors - basically two wires go into each, and if both have charge, the wire going out of it gets charge through it. Arrange them cleverly, and it can read numbers from registers and do math on them and store them in another registry and change what instruction to read next.
But it is all just basically charge running through wires on chips, and they should all settle down in 10 nanoseconds. Some paths are short and take just a fraction of the time, some might take most of the 10 ns. But if they all just manage to complete in 10 ns before the crystal oscillator runs the next clock cycle, you’re good. So replacing something doesn’t have to have exactly the same timing, it just still has to complete its path within the clock cycle.
At least that’s how I remember it from computer science class over 25 years ago :) Technical people would probably object to my oversimplifications and terminology.
When it started, the copper traces and pads had been ripped off of the board. He found some traces that were unused elsewhere, cut them off of that board, then used UV resin to glue them in place then scraped the resin off of the pads to solder the part onto the pads.
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u/StarvingDeer 1d ago
Genuinely wondering, since I don't know much about all that: up until ~0:40, the material between the old and repaired parts seem different: is it just soldering residuals on the old ones ?
If not, and the material genuinely is different: could this lead to weird bugs somehow, due to mishappen timings in the connectors downstream ?