Hi Hans,
I also agree with the knife method. I actually use a razor blade held in my hand (please wipe the blood off afterwards, ha, ha). It works well if one takes their time and is careful to make many scores to work through the pins without too much downward pressure which might accidentally cut a trace on the board. I consider it a fairly easy method.
73,
Gregg W7GRM
Today I tested samples of STM32F401RBT6 for a new batch of QDXs, to make sure they're the real deal not something labeled to just look real. We live in strange times.?
The only tools used (and available) are my cheap 60W temp controlled iron with 2mm tip; regular 60/40 solder 0.75mm diameter, solder wick, and a sharp knife. There is nothing special in this tool set.?
The knife is for cutting the pins of the chip being removed. Then remove the stubs carefully with the soldering iron. The traces are 10 mil. Then solder the new chip at the corners to get the alignment correct. Then the whole of each side, using plenty of solder not caring about shorts between pins. And finally the solder wick to remove all the excess solder and magically all the shorts.?
Success! Works! See attached.?
I have no idea if this would be easier with a proper SMD rework station, I've never owned or used one.?
-------- Original message --------
From: "Syd via " <nhuq1=
[email protected]>
Date: Sun, Oct 31, 2021, 12:30 AM
To:
[email protected]Subject: [QRPLabs] removing SM ICs
In the troubleshooting documentation there is a reference to using a hot air station for removing SMDs. Then it says that is OK for some other PCBs, but not the board for this kit. It even mentions snipping away pins with a "very sharp wire-cutter and snip each of the pins right next to the chip body"!? The synthesizer chip in this kit is a very small SMD and one needs a magnifying glass to see the pins!? Putting? a SMD back onto a PC board requires a lot of skill just to align it correctly, and then after that it requires a special solder that flows over the pins and then removing the excess solder afterwards. I saw this process on UTube and it is not easy to do.I do know that practice kits are available to learn to do this but I for one am not looking forward to learning this skill. So far I only had to go use a hair pin once to remove a short between two pins on the synthesizer IC. I got lucky!? Other than that I do not recommend doing anything else with these SMDs, just talk to Hans. Forget this section of the troubleshooting section.
syd/wt1v
