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gubbish

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  1. One other bit of information, I checked all of the address lines between the CPU and the UI8 glue chip, and got good continuity on all of them. Was kinda hoping I might find something there, as I happened to see another simasimac thread where one of those traces was bad. But, no luck this time. Only other thing I can think of at the moment is to directly test continuity between address/data/cs and the chips on the ROM SIMM itself, not the socket pins on the bottom of the board. May try that later today. Also can take a look at what's happening on the data lines during a run, since
  2. I eventually figured out which pin on the glue chip was connected to the ROM_CS and ROM_OE pins, and they had continuity. Did a bit more testing, tried running the board both with and without the ROM Simm. Without the ROM, all address lines were pulsing, and did appear to be counting up through the full address space. ROM_CS and ROM_OE were at ground, no activity. With the ROM, address lines had activity, and ROM_CS/ROM_OE had activity as well. So far no obvious broken traces or shorts that I could find. No more ideas for tonight, maybe more tomorrow. Any suggestions for
  3. A bit more information - I tested all the address and data connections between the ROM socket (bottom board pins) and the CPU bottom board pins, and I got continuity on all of them. There was a momentary bit of excitement when I thought that D8 and D9 were not connected, but it turned out that the pinout of the 68030 I was looking out was incorrect. Unfortunately the top search result for that had some errors - there were 2 different D19 pins, no D17 pin, and D8 and D9 were reversed. I attempted to check the ROM_CS and ROM_OE pins as well. Looking at the schematic these were connected to
  4. Ok, just looked at the schematic and saw that the A0/A1 lines are not connected to the CPU. So.. will keep looking.
  5. Well, good (?) news, I could not resist testing out some of the connections between the SIMM and the cpu until evening, and so far it appears that both A0 and A1 are not getting continuity between the appropriate pins on the SIMM socket and the CPU socket on the bottom of the board. Was easier to test between the sockets first so starting with that. At first I thought I just had the pins all wrong but then I saw that A2 and other address lines were in fact connected. So, maybe some actual faults here. Will map out the whole thing as soon as I get some more time to do so.
  6. If it's useful information, I have a second fully working SE/30 that I recapped years ago which recovered that Mac from the beginnings of a Simasimac situation. If there's any useful comparison between the boards that can be done, I can do that.
  7. Hi all, It has been a long time since I have been on the forum but happy to be back! Not so happy about the state of my attempted repair of a Simasimac SE/30. I recently acquired an SE/30 with some issues from a local seller, it sounded to me at first like it was going to be a problem with the analog board but turned out to be a Simasimac situation. It's in the vertical stripes stage, not the full on horizontal bars. Checking out the board, while it appeared in pretty good shape, I saw evidence of leaking electrolytic around the caps. In the audio section of the board, some of
  8. Hi, It's been a while since I've been on the forum, and it's nice to be back. I recently got a Mac Classic that was being given away. It appears to be in good shape, case-wise. However, there are some issues booting up. The logic board seems to be ok, as it makes a startup chime and comes up to a floppy-with-question-mark icon. I attempted to boot it with system 6.0.8 and 7.5.3 startup disks, but in both cases it just ejected the disks with an 'x' over the floppy disk. I cleaned the floppy heads with alcohol and a q-tip, but no change. I'm thinking something may be wrong with the flopp
  9. Here's the table of Sad Mac codes: http://support.apple.com/kb/TA46376 Looks like 040200 translates to bad RAM at location G6.
  10. Thanks.. The CC is now outfitted with Fetch, WhatRoute, and MacWeb for (very basic) web browsing. And I can pull software from my modern Mac with FTP. Joyous day. Thanks very much for the help.
  11. Thanks for the info, In the end I opted for the total destruction option, and just reformatted and installed System 7.1. There were no real incidents of note during this process, other than the fact that after 7.1 had fully installed and rebooted, that when booting from the HD, the same dialog of "7.1 is not supported on this model" came up.. and I rebooted from the Disk tools disk, and copied Enabler 401 onto the system folder of the HD. That did the trick and now it's booting into 7.1 nicely. Next step is to get the ethernet working - I installed the asante drivers for the card. Amazing th
  12. Thanks very much for the tips, I'm happy to report success! While the color classic would not boot with no PRAM battery at all, when I swapped in a good battery that I had in the aforementioned LC 475, it worked! I'm glad this turned out to be a simple fix. This Mac looks like it was in an elementary school, and has something called "At Ease" installed - basically it locks down everything unless you have the "Teacher" password. Looks like it's time for an OS reinstall. What's a good version to run on a color classic?
  13. Hi, It's been a while since I visited here, but it's good to be back. A recent rescue: I just saved a Color Classic from someone who was about to bring it to the recyclers, and would like to nurse it back from its current non-functional state. I do have another CC which is working, so I could potentially do some testing there if needed. So far, I did the following - - removed the logic board, and tried to power up without it. The fan comes on, so I'm thinking this means the analog board/power supply are at least partially good. - removed PRAM battery, replaced logic board, tried t
  14. I had a very similar symptom in a Mac Plus. Distorted bong, video strangeness, sad mac with strange pixels. It turned out that it was bad RAM - two of the SIMMs in that Mac turned out to be bad. Replaced them and it worked fine. Might not be the same problem with yours, but it's easy to test at least.
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