EEVblog Electronics Community Forum
Electronics => Manufacturing & Assembly => Topic started by: davegravy on December 06, 2024, 06:50:06 pm
-
I need to desolder a large SMD module from a board and due to the large RF shield on top I can't use (exclusively) hot air, I need to heat from the bottom. I can't use an oven due to plastic components, I need to be targeted with heating. The area immediately below the module is clear but there are obstacles (including plastic ones) nearby so I can't use a hotplate, at least not a standard sized one.
Is there such a thing as a mini-hotplate, something around 1" x 1" that the bottom of the PCB can be thermally coupled to below the target IC, maybe with a thermocouple that can be put on the top side for temperature control?
Or would it be best to use a regular hotplate with something like an 1" cubed aluminum block to conduct the heat to the desired area?
-
Thermally conductive block can be helpful. Or you can try to heat with hot air from the bottom. Similar to the method described below. But not from top of the PCB in your case.
https://www.eevblog.com/forum/repair/removing-tqfp-128-package-with-thermal-pad-from-double-sided-board/msg5523502/#msg5523502 (https://www.eevblog.com/forum/repair/removing-tqfp-128-package-with-thermal-pad-from-double-sided-board/msg5523502/#msg5523502)
-
A 1" square x 6" bar of aluminum is about $12 including shipping on eBay in the US. All you need is a short piece + a few spacers. Shipping has gotten so darn expensive, it would probably cost more to ship it to you than you can get it locally. Are you near any large American city, like Detroit?
-
Does 31x31mm fit? https://www.aliexpress.com/item/1005001800667409.html (https://www.aliexpress.com/item/1005001800667409.html)
There are also mini PTC heaters that you could tape onto the bottom of the board, though you cannot set a temperature, you just buy whatever preset temperatures they have.