Replacing SNES CPU from a donor

[eidis]

 Hi Guys !

I have two dead SNES units. One has faulty main CPU and the other has flaky motherboard. I would like to remove the main CPU from both boards and revive the motherboard with the bad CPU. Can anyone recommend a safe and effective way of how to do it ?

It's the big one in the left bottom corner.
https://warosu.org/data/vr/img/0015/60/1398062929504.jpg

Keep the scene alive !
Eidis

[unshe]

Some hard work there

Clean all parts whit isopropilic alcol.
Use a hot air station and something to grab the cpu, like a manual  pick-up tool.
Remove the  tin from the pad of the board u are going to fix whit a solder wick.
Clean another time whit alcol.
Put some flux, a lot of flux better, over the pads.
Use the drop technique whit your iron, if you make some bridges between pins don't worry, u will fix at the end, just put flux and suck the tin whit the copper wick, it is very easy.

Clean for the last time whit alcol, and test.

If something is not clear, just ask.
Good luck

[eidis]

 Hi Unshe !

Thank you for the detailed instructions, it looks like flux is the key to success. Here are the main questions which worry me:

1) What temperature would you recommend for the hot air station and soldering iron ?
2) The SNES is not ROHS so will 230-250 deg C be sufficient for the hot air station ?
3) Also, what are the requirements for the soldering iron and its tip ?
4) Do I need concave, flat or other soldering tip ?
5) Is there a FAQ somewhere which explains the meaning of various soldering tips ?
6) Would you advise using Kapton tape to cover the top of the chip before blowing it with hot air ?
7) Can you give recommendations what to do and what not to do to increase the chances of desoldering the chip without damaging it ?
8 ) Could you please post a link to YouTube video which shows a good example of the drop technique ?

Thank you in advance and sorry for so much questions. SMD soldering is a gray area for me

Keep the scene alive !
Eidis

[unshe]

hi,
Yes, flux is the key!

350 - 400 C for hot air worked well for me whit both snes's PPUs. For resoldering em whit iron, 300C is enough, or a little more too.
No need of concave, a flat tip (seems a screwdriver) is ok.
No idea about FAQ, but look on youtube, you will find a lot...
The cpu has enough free space around, so no need of kapton tape.
About desoldering whit hot air: I think that the right way is to warm up the entire chip whit a big nozzle, but i user just a round thiny one, like 6mm diameter, going in a continuous circle over the pins.
This is a good tutotial for smd soldering EEVblog #186 - Soldering Tutorial Part 3 - Surface Mount 

[eidis]

 Hi Unshe !

Thank you very much for the valuable information. This made a lot of things much clearer and it will come in very handy in the future but first I need to completely upgrade my gear. Thank you once again !

Keep the scene alive !
Eidis

[unshe]

U are welcome.

keep us updated!