General Category > LisaList2

Edge Connector for the IO Board

(1/4) > >>

pintoguy:
I'm working on repairing a corroded Lisa 2/5. The IO Card edge connector on the motherboard was so corroded that after cleaning, a few pins got loose and broke off (see bottom pic). I bought a new 2x60 pin connector on eBay, but upon trying to remove the old connector, I realized how extensive of a job that is and thought I could just remove the right-most 8 pins (2x4 - see top pic). I used a hot blade, and it was quite a bit easier than I thought ( I still messed up a couple of traces removing the soldered pins  :( ). I could then simply do the same with a cheap 36 pin connector and abut the new 8 pin bit to the existing space. Has anyone tried this ? Would anyone think it's a bad idea ? If it IS a bad idea, how's the best method to remove the 120 pin connector ?

blusnowkitty:
Removing connectors, either be patient with an iron, wick, and lots of flux, or pick up a desoldering gun. Hakko makes a nice one if you're willing to spend the money, and I've heard decent things about the generic Chinese ZD-915.

I don't see any physical reason why chopping two connectors apart wouldn't work, but electrically I'd be concerned with the two pieces being physically different in some way - either one or the other is taller or shorter than the other, or there's a slight angle one way on one connector and an angle the other way which could lead to a bad electrical connection.

You would probably want to remove the connector completely anyway. I have seen a couple Lisa backplanes have broken traces that were invisible as the break happened directly under the connector body.

AlexTheCat123:
As long as the new connector has the same dimensions as the old one (with the exception of it being shorter and having fewer pins), I don't see a problem with this. But it would obviously look better (and maybe be more reliable) if the entire connector could be replaced at once.

It can definitely be done with solder wick, but it's not a fun process! When I first got my Lisa, I had to desolder all four connectors this way and it took around 10 hours since the corrosion on the solder joints made things even harder than they would be otherwise. I would highly recommend getting one of the Hakko desoldering guns; it's a bit expensive, but super useful and it can remove one of those connectors in 5 to 10 minutes.

But if you don't care about aesthetics or just want a temporary solution, splicing in part of another connector should work perfectly fine!

pintoguy:
OK thanks. I ordered both the full 120-pin one, and a small one. The small one is black, so it matches the color of the existing connector. The full one is green, so it will contrast with the CPU connector that's black, so perhaps I'll opt for the cut-out solution. I'll report after I get the parts.

And thanks for the tip on the desoldering unit. I might do the investment....

pintoguy:
Update: I'm fairly happy with this repair. The color, height, and width match, and once the IO board is in place, it's hard to see the junction. I repaired all the traces, and the system looks like it's booting up: the on/off button is now dark and lights up upon switching. I can hear the speaker make some noise after 5 secs or so, then a series of beeps after ~15 secs: hi hi lo (no keyboard/mouse: expected) and hi hi hi (no startup device: also expected). But.... no video. I'm not too worried about this one, but who knows...

Navigation

[0] Message Index

[#] Next page