68kMLA

ew!

QFP nightmare

Now we know why they were sold on cut boards...

Looks like it may have been conformal coated? You might have better luck with hot air from beneath the board to remove the QFP; it can be a little risky with boards you actually care about but with these little stubs, turn it up and give them hell.

@zigzagjoe would you use a board preheater for that?

I don't think preheaters will go that high. I'd just clamp the board stub however you have means to and directly use hotair on the bottom of the board, at higher than usual temps and max flow. Make sure to do this in a ventilated area as you will likely scorch the bottom of the PCB.

+1 on ensuring good ventilation before trying that method. Whatever comes off that board isn't going to be good to breathe...

just yolo it with a creme brulee torch tbqh

heatgun ?

Just to check, the CPU itself won't mind the extra heat if coming from below the PCB?

I do that upside down and got some results but with qfps it's anoying because not all pins heat at the same time so sometimes a few of them get bent when the CPU fall off

With PDIP and PLCCs as well, most of them are working after. Tap gently on the PCB with some wood something to get the part to fall faster

how expensive are theses ?

IMO heat-from-below is kinder to the CPU, it should remain cooler since heat transmission to the CPU is largely occurring through the legs. As you can really nuke the board, it should be a quicker process to remove where most heat is applied where it needs to be (the joint between CPU and PCB) leading to less heating of the CPU. (As opposed to soldering iron directly on leads to work in chipquik and keep it hot)

As demik pointed out though you should use a vacuum tool to lift the QFP off, or if doing upside down have a very small gap between the board and something for the chip to fall on.

@demik they’re 68040FE33 chips, not particularly expensive but basically unobtainium

Are you doing blackbird shenanigans ?

@demik Yes!

where'd you find these chips?

@alectrona6400 Eric Woo on eBay sourced them for me, though he struggled apparently as there are very few around.

ohhhh, thought yall found a board that was under the radar. cos i would love to have a full 040 in my powerbook 520 ^^