Never understand why so many people blast these old boards with hot air to remove components. I've got a video showing 40-pin IC removals using solder sucker. Takes a few minutes, gravity makes the chip fall out, and absolutely no damage is done.
Back in the 90s used to work for a well known manufacturer of PC compatibles and they ended up with a prised customer who constantly returned boards as faulty (as they had broken the oimm or dimm sockets) but because they bought so much kit our company wouldn't tell them they were idiots and simply absorbed the costs I got so tired of it I started to replace the killers bybhand and it used to take me about 20 minutes to desolder a SIMM or DIMM socket and install a new one, with a 90% success rate (the failed 10% had been mashed even further by the prized customer) That was on 5 layer boards, with a cheap antec soldering iron and a £5.00 solder sucker so I can't see why a 6502 (or a 68000) can't be removed cleanly and safely in a few minutes
Just watched your video. Very good. I'm always terrified of lifting pads and rarely get chips falling out, so I'll follow all your good advice about pressure etc. Thanks!
I wonder if they used hot air to solder the socket back in, and that second heat caused the delamination and the socket bridge obscured that damaged via. They should of tested it though. Great video. I didn't know hot air could delaminate old PCBs, so very useful bit of knowledge to look out for.
I don't know. In my own experiments, I've found it's possible to inflict exactly the kind of damage seen in the video (and worse) simply by heating a 40-pin DIP package along either side with hot air until it can be levered out of the board. You can also end up with warping of the board, especially if multiple ICs are removed in this manner.
If I ever do that mod again, I won't be replacing the barrel jack with a DIN connector. It's probably possible to do a very neat job if you keep the barrel jack.
Hakko FR-301... on these boards full of through hole DIPs it makes life easy. This is also the reason I never use machine-pin sockets, if the round pin covers the hole with the conical shoulder at the top of the pin then air can't be sucked through and they are almost impossible to desolder. (Also the cheap ones are garbage and you will have to remove them. The ones that you won't need to desolder are $$$)
I watched the comparison video by 'More Fun Making It' of the ZD-915 and the FR-301, and I was pretty much persuaded by the FR-301, especially after a chat with the host in the video comments. As for the turned sockets being difficult to desolder: that's true, but as mentioned elsewhere in the comments, the client wanted the CPU socketed in order to test-install various round-pin-equipped CPU adapters/accelerators for which a turned-pin socket is a reasonable choice, so I don't have an issue with the other technician using that kind of socket. It's the manner of execution that's problematic, with particular reference to removal of the original chip. And full disclosure: if I'd had to remove that socket in order to repair the board, I would probably have ended up using hot air too. The difference is that I know the pitfalls involved, would be taking pains not to scorch or overheat the board, and I would repair any further damage that was sustained, ensuring that the board worked when it left my desk.
There really is no excuse for popcorning a board like that, it shows a lack of understanding about PCB construction. Probably too hot for too long in that one spot, I'm surprised it didn't do more damage. Good find. Personally I wouldn't have used a machined socket either, just a normal double-wipe type, otherwise you're putting a square peg in a round hole.
I think the intention was to put a round-pin adapter in there (like Antonia or similar), so maybe the machined socket would be a good fit for that. The only reason I can recognise the signs of hot air damage is that I inflicted the same damage on breaker boards myself when I first got a powerful hot air station and tried using it to remove ICs. DRAMs and other 14-16 pin packages are quite doable if you're careful, but 40-pin DIPs are another matter. In any case: the ability to recover seamlessly from mishaps is another important skill (I do that all the time), but in order to recover from a mishap, you need to know the mishap occurred. :)
yea this is where you shine...other techs may be good, they maybe bad...they take your box to some back room do xyz asnd return it...who knows what they did...with you, people see enough to know even if you didn't film a repair...you did turn it on and test before returning...as you never know without it what might be wrong.
Thanks. At the end of the day, who wants the hassle of the client telling you the machine doesn't work? And for the sake of an extra couple of minutes testing or pinging out the board. The technician apparently never offered a refund on this work, either.
