68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.
Macintosh IIci lifted pad - advice needed
Posted by: y2krecall on 2024-07-13 21:55:37 Hey everyone, I kind of got myself in a bind here. I was doing a recapping job on this Mac II, I’ve done a few other recap jobs with success so I felt like I was ready for this so I got a cap kit from Console5 and it’s been misery. I was not ready. I managed to lift a pad at C10 on the motherboard, and I don’t know where to bodge in. Anyone wanna help steer me in the right direction?
Posted by: finkmac on 2024-07-13 22:33:52 schematics here
Posted by: croissantking on 2024-07-14 06:40:18 Looks like here. Hope you are using the twist method to get the old caps off…
Posted by: y2krecall on 2024-07-14 07:22:46 Looks like here. Hope you are using the twist method to get the old caps off… View attachment 75783 I am, the recap was actually already finished and the board was chiming. It would get part way through the memory test, and then stop, no matter what i did. So I went back in and reflowed the memory sockets, same deal. I put it down for a week and come back and suddenly no chime. I just figured I needed to reflow the caps as before I did the recap I had no sound. That was the last cap I was gonna reflow and I noticed the pad lifted. I think the original symptom was rom failure but now I think it’s something worse.
Posted by: croissantking on 2024-07-14 14:37:19 This part of the board gets hit hard by cap leakage on every IIci board I’ve seen, don’t blame yourself. Here’s how I tidied up one that was in a much worse state than yours.
Posted by: y2krecall on 2024-07-15 15:45:28 Yeah, I noticed these are very fiddly to get working. I was very excited when I got a beep but the memory test, as stated earlier, would never finish. I bodged a new cap in, and it seems to be getting voltage. Some of the caps from console5 seemed a bit fiddly and I have also replaced some of the radial caps with caps I had on the shelf, not sure if that's an isolated experience or not. I've poked and prodded this thing to death - I attached a series of photos of the top of the board and if anyone sees anything I've missed please point me somewhere. I really hope to get this machine working since I've spent so much of my time with it. I've thought about trying a rom simm but I don't want to waste the time and money if my eyes are skimming over something electrical...
Posted by: finkmac on 2024-07-15 17:03:04 you seem to have a lot of... pet hair on the board? might be worth cleaning it off. also... you're using flux... right?
Posted by: y2krecall on 2024-07-15 17:12:42 you seem to have a lot of... pet hair on the board? might be worth cleaning it off. also... you're using flux... right? Yes, lots of pet hair. My cat sleeps on my desk, I clean it before powering on she's just a shedder and it gets everywhere. And yes I am using flux, do you think I'm maybe not using enough?
Posted by: finkmac on 2024-07-15 17:23:29 on second look, I do see the flux. perhaps your iron isn't hot enough. I also see some corrosion here:
Posted by: y2krecall on 2024-07-16 13:27:22 on second look, I do see the flux. perhaps your iron isn't hot enough. I also see some corrosion here: View attachment 75866 I did not notice that, I'll take a peek there. Thank you.
Posted by: imactheknife on 2024-08-02 18:02:55 I did not notice that, I'll take a peek there. Thank you. I have had to remove that sound chip on most of my iici projects due to cap leakage and broken connections from legs to pads, or broken traces etc
Posted by: chiptripper on 2024-08-03 16:09:26 You may have to reflow UB13, UD13, and UE13, Q3, Q4, D5, D6, etc. In some cases the solder is so degraded I have to scrape it off, it becomes like powder and won’t flow anymore. It’s a big problem area as @croissantking mentioned. Check continuity anywhere you see dull and dark solder or questionable joints. Some examples below.
1