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Amiga of Rochester

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  1. I won't lie, I probably won't take on many more Portables. I just fixed the classic I mentioned above. I agree with the idea of replacing the whole hybrid, how I'd approach it. I hope one day to offer this service to people, but it seems far off.
  2. Do we need to reproduce the exact function of the pwrmgr? wonder if its possible to do a new version with different functionality but makes the board work hah.
  3. but you did i just missed the line. i was so happy i almost cried lol.
  4. I must have missed it when testing (or just didn't notice when testing the 174 pads). but I found the break, it was a21 on the 174. I let this board get to me, but I overcame, definitely learned to check EVERYTHING and be sure you did. Maybe print it out and mark it off.
  5. Replaced the 257s, no change. Reflowed BBU, no change. Interestingly if I take 2 256 sticks, instead of booting it will crash with "0000000F" with 0021, always. Looking at the headers, I see no activity on the Column C CAS lines. It'll be high but never changes state. I'm doubting its a bad PAL as I've already changed it. I'd be more likely to suspect BBU isn't signaling the PAL or something...At this point the entire RAM circuit ICs have been swapped.
  6. You make me feel far better Any idea on this Classic I have that doesn't see SIMM ram? I have a thread on it. Could use any guidance. Plan to just replace most of the logic ICs related to RAM
  7. any chance you got one I can buy? I don't have a working hybrid to confirm with. I might have to just call it a lose, I don't want to spend a lot of money on something I might not solve. figured i'm already ordering some ics I could try swapping those...but seems less and less likely the issue.
  8. I need to order some capacitors, which ICs should I replace? I'm just going to try it for the sake. I am definitely going off your experience, I figure you have had the time invested. It's like Amigas for me, I know a lot about those from my time working on them.
  9. okay, took the scope out and A9 is definitely there, CAS/RAS are there, I see data on the output of the chip, I see data going in. Well, that's it for the night. Maybe someone has an idea.
  10. Confirmed RA9 all the way back BBU. Confirmed address bus (a0-18) back continuity all the way to CPU
  11. False alarm, chip was bridging somewhre, reflowing fixed that but not the issue...darn Are you sure they are the address? Seems like a typo on the schematic, they seem to be the data lines.
  12. So I measured between the left side of R8 and r7, they are shorted some how. the other side goes right to the damn socket...but they are definitely tied together some how.
  13. Swapped UL1, UH6 no difference. checked under UL1 while there, no issues. Same for UH6. Reflowed the socket header. im sure whatever this is, is something dumb. Confirmed continuity to the switch too.
  14. Board overall wasn't too bad. So, only thing to remember is it DOES see the 1MB on the expansion, just NOT the SIMMs. I feel this might rule out CAS/RAS a bit but I'm not 100% sure. I'd imagine if we were missing RAS / CAS we'd have either less memory but who knows. I'd need to see how RAS/CAS gets to the SIMM slots.
  15. Customer used their own module too, pins in the contacts are clean. Just swapping to another mac classic it works fine. So 2/2 fail Like I said, no results for this issue anywhere. Checked solder joints, all good there.
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