exxos's Atari, Amiga & retro forum

exxos wrote: 28 Oct 2018 09:44 Almost sad to see 70789 being butchered :cry:

It is kinda sad, that was one of the better 1040 boards, may it rest in peace. Had glitter possibilities to. I used a 70523-001 rev C. with no glitter possible. R_J did you use a soldering iron or hot air to remove the parts? I see you left the OPTO which is a good move. Enjoy the new board. :yay:

I tend to use a soldering iron with fluxed wick, and if needs be some liquid flux to help things along. I did use hot air on the sockets to pre heat the solder for wicking, but TBH I find these boards delaminate really easily when heated, so I try to avoid it. I have a desoldering iron too with a built in sucker that I use for heavy joints.

Not that it really mattered. In all honesty, I had tried to upgrade this board to 1MB as you can see from the sockets, but it just wasn't happy, and after buzzing out the sockets, there were so many failed data and address lines, plus there were floppy problems, I decided it should be my donor board, as repairs would have taken too long.

Consequently I haven't been over cautious with the removal of parts, so the board is definitely dead now, but the parts yield is good, I got 2 funky PLCC sockets out of it for blitter upgrades. :o

Saying that though, the PCB quality was way below what I've seen on other boards I've worked on, it was really susceptible to heat damage from the soldering iron, with vias failing under what would be normal soldering conditions. Maybe it was a duff board from the off, it arrived sporting bodge wires on the first 512k RAM, who knows?

I figured it was something like that. I just ordered a hot air machine to give that a try. The Atari boards suck to remove parts on, I find the solder is extremely oxidzed and every case for me different. I use plenty of flux and solder wick in most cases. Sometimes I find that the solder sucker is works better..

PaulJ wrote: 28 Oct 2018 15:23 I figured it was something like that. I just ordered a hot air machine to give that a try. The Atari boards suck to remove parts on, I find the solder is extremely oxidzed and every case for me different. I use plenty of flux and solder wick in most cases. Sometimes I find that the solder sucker is works better..

I also find that melting my own solder on is in some cases the only way to get the desolder process started. Hot air worked ok for the funky PLCC sockets actually, but you need to be really patient and not get too close to the PCB.

What temp do you use on the hot air?

PaulJ wrote: 28 Oct 2018 15:37 What temp do you use on the hot air?

Hmm, now you're asking, I don't recall. I do recall that it needed a lot of patience before the board got hot enough for me to remove the PLCC sockets though.

Good news, the last of my sockets arrived today, so I can crack on :)

rubber_jonnie wrote: 01 Nov 2018 12:12 Good news, the last of my sockets arrived today, so I can crack on :)

Back in the game :) - Good luck.

I am quite missing all that assembly time I had on the board.

Looking forward to getting the build finished so I can apply the fixes and test!!

rubber_jonnie wrote: 01 Nov 2018 12:48 Looking forward to getting the build finished so I can apply the fixes and test!!

Have fun :) :thumbup: