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warmech

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  1. Nice! Glad to see this is still marching along - I'd love to finally be able to replace all my dead or dying SCSI drives.
  2. Alrighty, back with an update! The chassis has been recapped and the two resistors replaced and, lo and behold, it powers up! Except now I have a vertical linearity problem and the screen jumps up and down like a Jack Russell Terrier. Adjusting the V-LIN pot all the way leaves several lines of foldover at the top of the display, and I have been unable to track down the issue. Not being able to find any schematics for these things isn't helping either, lol. In addition to the foldover, the image bounces up and down rapidly, but only as you increase the vertical image size. If you dial it back d
  3. I'd bet money on this being a culprit; I've had a few Macs with image geometry/stability issues before and after recapping where it turned out the opto IC was at fault. While this won't solve all of your issues, it is a cheap fix that more than likely will address part of them. My other bet would have been on DP6 as well, for what it's worth.
  4. Ran into a similar problem a while back; the on-screen pattern was slightly different, but the card was bad.
  5. That first image you posted makes it look like the nipple has broken off the back of the CRT. Is there a hole on the end of that tube where the bent pins are? If so, that tube is toast. Thankfully, they are all pretty interchangeable; you should be able to find a dead compact Mac for cheap that you can scavenge the CRT out off, though.
  6. The TL866II is what I use and it's pretty dang nice. It also has a TTL logic IC tester built in, which is incredibly useful in troubleshooting 74-series logic chips. It's about $50-60 on Amazon and worth every penny. As dochilli said, you'll want to dump your Plus' ROMs and compare them (the checksum, at least) to a known good copy of the ROMs; if the checksums are different, the ROMs need replacement.
  7. Well, that's about the coolest thing I've seen today. Planning on selling blank PCBs soon? Mouser is literally across town from me, so UPS ground gets here next day (I miss the days of same-day will call ). I would love to put a few of these together to drop into some stuff.
  8. Second on checking voltages; I'm guessing you tried the original "faulty" expansion card in another Classic as well? I suppose it is entirely possible that the original card is indeed bad, but you also very likely have another underlying issue on the logic board or analog board. But yeah, check the voltages; low voltages can cause all kinds of weird boot issues. I ran into all kinds of funky behavior with my (now dead) Classic II; come to find out, the +5v rail was too low for the logic board to work consistently.
  9. I'll echo all of these sentiments, and Scuzzino sounds amazingly on-point!
  10. Very interested; depending on the price, I'd be down for several. Heck, I'd be down for several blank PCBs and a BOM at Mouser; I have no issues assembling something like this. I've got several Macs that have dead hard disks and can't exactly afford to drop a SCSI2SD in every one of them.
  11. After working on my IIx to get it up and running, I've been wondering about something. I have a dead, and almost certainly unrepairable, IIfx (there's something screwy going on in the NuBus section, in addition to exploded batteries that I've been fruitlessly repairing damage from) with a 40MHz 030 in it that I know works. Can the 16MHz 030 in the IIx be pulled and swapped out with the 40MHz 030 in the IIfx, or is there a fundamental architecture issue that would prevent this?
  12. AARGH - RAM! After testing in my Classic, two of the four 1MB SIMMs are bad. The Mac IIx can boot off of 1MB of RAM, so long as it's in the form of four 256K SIMMs in the four seats in bank A. Now that I'm down to two 1MB SIMMs, I need to take something apart to test with other SIMMs. EDIT: Huzzah - I now have a working Mac IIx! Grabbed the RAM out of my SE, dropped it in, and it fired right up! I'm thinking this is case closed.
  13. I can take some high res images in a little bit and post them here; a broken trace is my worry, as well. All of the RAM I've tried aside from the SIMMs that came with this thing give me no boot chime or error tones, just slow chimes (as opposed to the boot chime/error tones/fast chimes with the present config). I'm... not really certain why that's the case either. The IIx seems to accept 256K/1M/4M SIMMs, so I may dig around and see if I can pull RAM from another machine and try that. At lunch, I plan on trying out the diagnostic mode outlined here: https://mac68k.info/wiki/display
  14. Replaced with a working 74F240 to no avail; back to the drawing board.
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