@amiga_3k:
You're correct in that if the solder job is not well done, the alcohol or other liquids might sip through. But what I think happened was that the alcohol didn't sip through to the other side, but because I put so much of it, it just overflowed and went around the board (the board wasn't horizontal the whole time). My solder job is pretty good too, so I had made sure there were no holes or anything of the sort. Of course I can't be 100% sure on that, but I think it's ok (based on other jobs I've done). But right now I can't take that stuff apart, because I have no more solder wick, and it was such a pain in the butt taking the Chip RAM out, to begin with. But even when I took the Chip RAM out, I didn't find ANY bad chips. So the problem was not the Chip RAM. It's someplace else...
Thanks for the idea though
@Framiga:
Yes, I've done a little 'via testing' but not much, because it's hard to get the board to stand up... I'm not a pro, and I don't have the right equipment. But yes, the problem is definitely with the motherboard or the chips I could not test, but I don't think it's the chips because the computer was working solidly. It's the battery the killed it, I'm 99.9999% certain.
"Multo grazzie", I'll need lots of luck!
@Castellen: (<-- this guy is my hero! without him or his site my A4000 would be dead or trashed by now!)
I'll take a paragraph approach on this one:
History:
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I believe the problem is due to the leak, as might be evident from the history so far: the machine worked fine for a decade almost. Around 2000 I noticed the battery get fuzzy, but no real spillage. No scars, no corrosion on the mobo. Removed it, cleaned the area with, I believe, wet with water Q-tips and the like. I don't think I used any sort of alcohol, but it's been too long to remember. Left it sitting until 2005 (I know... now I'm paying for it). Turned it on around May 2005, and I _believe_ it booted to some sorta ok state (Kickstart screen or even WorkBench, I forget). Turned it off and then on again and it green screened. As soon as I saw that, I opened it up again and saw that inside it had a few nasty scars, not only where the battery was, but specs of scars around the surrounding area. But they were small scars, like it had drizzled acid. No big scars or corrosion, except where battery negative terminal was. Also, no corroded ICs or sockets, or pins. Just a bit of green/blue (tirquise?) on some pins, like the resistor and cap north of the negative terminal and a couple of the ICs near there (U480, U477, U472).
Typical things:
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I did reseating of all these ICs: 2xCIA, SCSI, Agnus, Paula, Denise, Chip RAM, Kickstarts (2.04), RTC, 4xGAL chips on the Chip RAM side, disabled FPU, removed all Fast RAM for now. Maybe I should do _all_ socketed ICs like Amber, Gary, Ramsey etc? Would any of the ones I didn't reseat cause a green screen? (I don't know which other chips access Chip RAM). I also tested the following on my A500: 2xCIA, Agnus, Paula, Denise. All worked flawlessly.
[EDIT: I resat all socketed chips. I read someplace that Gary could possibly cause green screen].
Socket repair:
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I will use your method, but I prefer to use sockets, so I will go buy some good ones (machine pinned as you said), and remove the existing and stick the new ones in. And yes, the ground/VCC pins sucked big time because of the 'heatsink' effect. Especially when trying to remove the Chip RAM. But for informational reasons: I did re-heat/re-solder (what's the right term?) the actual socket joints for many of the ICs in the area (Agnus, Paula, Denise, part of the video circuitry, RTC and a couple of the surrounding chips). Nothing changed
Advanced terms:
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It's near impossible to create a "bad" solder joint with plated through hole technology. Usually the worst thing you can do is have solder shorts, but you've got to be pretty bad to do that with component technology this big!
This went a bit over my head
Can you explain the "plated through hole tech" ? And as for "solder shorts", do you mean because the holes are too close? I've been very careful, testing with my DMM to make sure there are no shorts.
[EDIT: I understand now, and I agree 100%]
Isopropyl:
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Yes it looks a bit worse than expected, and at some point I thought it might have to do with the soldering job. I'm not so sure because of one thing: the Chip RAM I desoldered were the last 2 banks, 8 chips. The farthestmost bank (4 chips, 0-512KB) did not have any of the white gunk left afterwards. But the 2nd from farthest bank (4 chips, high 512-1024KB) had tons of it! And it's not like I did anything special when desoldering/soldering the 2nd set... Also of note: the next 2 banks (1024KB-2048KB) didn't have any gunk. Of course these were soldered from the factory and I didn't really touch them.
As for the purity, I agree with ya: I'll keep the high quality stuff for my meth experiments and use the 70% for 17 year old motherboards
And the damn alcohol is so expensive for such a common "ancient-tech" thing...
PCB layers:
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Thanks for the "lonely vias" tip! That is really really helpful, so now I can track and see if there is any inner-layer usage near the scars! And yes, of course I've been using your "via repair" page to guide me along this Herculean task
Thanks again for all the info/tips/help Castellen!
I think Wayne's server drives must be chocking right about now!