Yes. ?You need a QRPLABS encrypted boot loader programmed on the CPUs. ?I have some on hand for the repairs that I do. ?Ask Hans if he has one he would sell to you.
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when soldering in a new chip, I do this:
1) clean off all pads with flux and solder wick. ?Be careful not to be too aggressive moving on the 100 pads. ?They are delicate.
2) clean off residual flux with 99% IPA
3) coat all pads with a viscous no clean flux
4) place new cpu on pads - getting pin 1 correct!!!
5) fiddle until all the pads are aligned and near perfect with equal space?
6) with a really tiny tipped iron, coat the tip with a very small blob of 60/40 solder
7) press down on top of the cpu with a finger or small instrument so it won¡¯t move. ?Keep the pressure here and check all pins
8) touch the iron to a non GND pin on the cpu anchoring that pin
9) repeat tack soldering a pin on each side until all 4 sides have one pin tack soldered.
note: if you have solder bridges at this point - don¡¯t worry. ?We will get them later
10) coat all pins with fresh flux carefully. ?Dragging a tip across the pins will bend them. ?Not good!
10) now with a larger iron (I use 1.2mm chisel tip) drag a bead of 60/40 solder gently across a row of pins.
11) repeat for the other three sides
12) I now put another bead of flux on top of the soldered sides.
13) with my 1.2 mm tip I gently touch each pad and the edge of each cpu pin. ?The solder will reflow and clean up many bridges.
14) if you have stubborn bridges, use a 1/2 second dab with solder wick and my iron.
now inspect everything under high magnification and bright lights. ?look for fully soldered pins and no bridges (x100). ?Gently poke the side of a pin that looks suspect to make sure it¡¯s soldered down well. ?I use a dental tool for that
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good luck
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73
Jeff Moore
W1NC
