Sherry Haibara
Well-known member
Hello everybody, I'm back again with another conquest of mine!
This time luck has brought me nothing less than a Macintosh 128k, which I obtained from a guy in Italy.
Now, the story of this poor guy is an unhappy one, unfortunately. The guy who sold me this one said it was in working order and that he had found it in the garage of a friend, but of course that wasn't true - in fact, I discovered that he has bought this machine more or less a month ago from an american guy on eBay with defects. So now I have an open dispute with him to try and get back some of the money, but meanwhile I'm trying to get this poor thing back into working order.
First defect: I think the AB is probably toasted. As soon as I plugged it to the power line (using a 220V to 110v converter, since it's a 110V one), it started making very unpleasant sparks and fireworks... I'm assuming the previous owner tried to connect it to the 220V straight, unfortunately. I'll have to do some more investigation about this, though. I'm not excessively worried about this, as I think I'd be able to source a working AB if everything else fails.
What worries me more is the second defect, which appears to involve the logic board.
I put the logic board into one of my Macintosh Pluses for testing purposes, and instead of nicely booting with the chime it only makes a couple of "ticks" from the speaker and shows a vertical line pattern on the display which resembles the infamous simasimac of the SE/30. Also, sometimes it doesn't show anything on the screen at all, and when it shows lines they eventually disappear from the screen after a few seconds. If the floppy drive is attached, it also tries to make access to it. t'm attaching some pictures.
So I looked at the logic board, and something interesting is going on here.
First of all, it has been upgraded to use Macintosh Plus ROMs: the high rom is a 342-0341-B chip and the low rom is a 342-0342-A chip. Apparently, this is because they replaced the original 400k floppy driver with a newer, 800k one. Both chips have been tried on a different logic board and work fine. Also, I've tried to replace them with another set of known-to-be-working Plus ROMs, but the defect is still the same.
Secondly, at some point someone must have tried to perform a RAM upgrade, as there are strange connections around a couple of chips. At this moment, the chips are all MT 4264, which should be appropriate for this having 128KB of memory, although they don't seem to be the original ones as they don't have the Apple logo on them. It seems the issue is very similar to this one, which however also involved damaged rom chips.
Next week I'll probably bring this little boy to ferrix and see what we can do, but I'd like to ask you what should we try first.
In particular, do you know what exactly that modification could be doing and how we could revert it to stock? Is it possible that one (or more) memory chips have died?
This time luck has brought me nothing less than a Macintosh 128k, which I obtained from a guy in Italy.
Now, the story of this poor guy is an unhappy one, unfortunately. The guy who sold me this one said it was in working order and that he had found it in the garage of a friend, but of course that wasn't true - in fact, I discovered that he has bought this machine more or less a month ago from an american guy on eBay with defects. So now I have an open dispute with him to try and get back some of the money, but meanwhile I'm trying to get this poor thing back into working order.
First defect: I think the AB is probably toasted. As soon as I plugged it to the power line (using a 220V to 110v converter, since it's a 110V one), it started making very unpleasant sparks and fireworks... I'm assuming the previous owner tried to connect it to the 220V straight, unfortunately. I'll have to do some more investigation about this, though. I'm not excessively worried about this, as I think I'd be able to source a working AB if everything else fails.
What worries me more is the second defect, which appears to involve the logic board.
I put the logic board into one of my Macintosh Pluses for testing purposes, and instead of nicely booting with the chime it only makes a couple of "ticks" from the speaker and shows a vertical line pattern on the display which resembles the infamous simasimac of the SE/30. Also, sometimes it doesn't show anything on the screen at all, and when it shows lines they eventually disappear from the screen after a few seconds. If the floppy drive is attached, it also tries to make access to it. t'm attaching some pictures.
So I looked at the logic board, and something interesting is going on here.
First of all, it has been upgraded to use Macintosh Plus ROMs: the high rom is a 342-0341-B chip and the low rom is a 342-0342-A chip. Apparently, this is because they replaced the original 400k floppy driver with a newer, 800k one. Both chips have been tried on a different logic board and work fine. Also, I've tried to replace them with another set of known-to-be-working Plus ROMs, but the defect is still the same.
Secondly, at some point someone must have tried to perform a RAM upgrade, as there are strange connections around a couple of chips. At this moment, the chips are all MT 4264, which should be appropriate for this having 128KB of memory, although they don't seem to be the original ones as they don't have the Apple logo on them. It seems the issue is very similar to this one, which however also involved damaged rom chips.
Next week I'll probably bring this little boy to ferrix and see what we can do, but I'd like to ask you what should we try first.
In particular, do you know what exactly that modification could be doing and how we could revert it to stock? Is it possible that one (or more) memory chips have died?