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SE/30 video issue that has ME stumped!
- Thread starter techknight
- Start date
Well, if you've swapped every suspect chip on that board, the only things that could be bad are traces... I know that's kind of a stupid suggestion, but I would go bad trace hunting with a schematic if I were you.
https://www.macintoshrepository.org/875-macintosh-se-30-schematics-and-repair
https://www.macintoshrepository.org/875-macintosh-se-30-schematics-and-repair
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yea thats commonly fixed. If you have already changed out UE8, then check the traces to it.
But more importantly, check the VRAM I have seen those go bad as well.
But more importantly, check the VRAM I have seen those go bad as well.
Yeap, I figured as much.
the board I have is way worse. lol.
the board I have is way worse. lol.
Sorry to dig up a dead thread.
Techknight, did you ever find anything on this? I have precisely the same video bug, but cant seem to figure it out. Both VRAM's and UE8 have been replaced. Tested all traces to and from VRAM. I still get vertical stripes with a slightly abnormal disk icon. Looks identical to your screenshot.
Techknight, did you ever find anything on this? I have precisely the same video bug, but cant seem to figure it out. Both VRAM's and UE8 have been replaced. Tested all traces to and from VRAM. I still get vertical stripes with a slightly abnormal disk icon. Looks identical to your screenshot.
ISSUE RESOLVED! Techknight, you may want to add this to your notes.
It appears that Texas Instruments SN74HC166DRG4 is NOT a valid replacement for the the 166 shift register @ UE8. It causes the discussed artifacts.
I swapped it out again, but this time with a Toshiba 74HC166D, and the issue completely resolved!
It appears that Texas Instruments SN74HC166DRG4 is NOT a valid replacement for the the 166 shift register @ UE8. It causes the discussed artifacts.
I swapped it out again, but this time with a Toshiba 74HC166D, and the issue completely resolved!
You cant swap in an HC for an LS, because that is TTL vs CMOS, they have very different logic level High and Low thresholds.
And yes, I checked for that, although its been a very long time, I can check again as if I recall, I dont know if I was the one who changed the IC.
And yes, I checked for that, although its been a very long time, I can check again as if I recall, I dont know if I was the one who changed the IC.
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So, I pulled out that board, I had to remember where it was as its been a couple years. Sure enough, it has an HC166 in there.
Didnt even think about it honestly. I checked my stashed that I was using and all of mine are LS166s like they are supposed to be.
Didnt even think about it honestly. I checked my stashed that I was using and all of mine are LS166s like they are supposed to be.
Thanks everyone for sharing your repair experiences, it was an awesome help to finally get my SE/30 recapped and fixed. I was stumped by the black vertical lines but after inspecting the corrosion damage around the old caps under a microscope and thinking that maybe there's something I'm not seeing, I finally desoldered UE8 and found the broken trace. A bodge wire later and my SE/30 is good as new.
Now that I have a microscope it's making me really want a ultrasonic cleaner because the corrosion looks really disgusting up close and brushing with IPA apparently just smears it around
Now that I have a microscope it's making me really want a ultrasonic cleaner because the corrosion looks really disgusting up close and brushing with IPA apparently just smears it around
