I recently took on a repair and I am dealing with solder I have never encountered. It is a scooter that quit working, error code states low motor voltage, even though the battery is good and fully charged. I removed the controller, the mosfets appear fine, so I suspect the relay contacts. Unfortunately, the solder that was used barely melts at the max setting on my soldering iron (480°C) and there are surface mount components including electrolytics all around the relay and underneath it. To make things worse, the relay is soldered into plated vias. So far, I have used an entire stick of ChipQuik with a solder sucker and managed to get the coil leads free and most of the solder off the contact legs, but I struggle getting the solder inside the vias to come out or even melt. The relay won't budge. I plan to keep going with the chipquik alloy, but I wonder how many rounds of getting them hot it can handle before I destroy other things. Does anyone have advice for a situation like this? I would try hot air, but there are SMD electrolytic caps and other chips right next to the relay and I fear hitting it that hard will do damage to them as well.
edit: another concern I have is whether or not the chipquik is getting in the via and that the relay is simply glued down, but given how many rounds of chipquik it took to get the bulk of the solder off the legs would suggest its just that high of MP. I want to try to get under the relay and pry, but there are SMD resistors under it and I don't know what might peel off with the glue that may be there. They built this thing to not be repaired. I am tempted to decap the relay to check the contacts and cut it out if bad.
Any suggestions would be appreciated, thanks!