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JC8080

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  1. As @JDW mentioned, and as you can see in my photo, it was necessary to drill a second hole so the leg would reach the board.
  2. I don't think I have a photo of it installed, but that's how I did it, I was just very careful bending the leg. I also put thermal paste behind the diode. And yes I think it might be easier to clip the diode lead for the axial ones, though the leads on those diodes are very thick so I don't think a small set of cutters will do the job. Personally I wanted to keep it looking as original as possible, not that anyone other than me will ever be digging around inside.
  3. The new CR20 and CR21 do not come with the heatsink, you will need to re-use the old heatsinks. When I replaced these parts I removed the heatsink from the board with the diode still attached. Then I removed the old diode from the heatsink and replaced it with the new one, and reinstalled onto the analog board. It may be possible to replace the diode without removing the heatsink, maybe someone here can comment on that. Be aware that un-soldering the diode from the heatsink can be a bit tough, the heatsink very effectively dissipates the heat from the soldering iron, making it hard heat up
  4. @JDW helped me through the project, so he has all the good info!
  5. Ah sorry I didn't realize you have the international analog board. I believe JDWs list of recommended replacements is based on Larry Pina's book Macintosh Repair & Upgrade Secrets. I think if you look at page 126-131 you will see Larry's recommended upgrade parts, which I believe are for the US analog board. If you look at page 335 of the book you will find a listing of all parts on the international analog board. You could probably do a bit of cross referencing, and you might be able to find which diodes/rectifiers need to be upgraded. On the US board, CR1, CR5, CR15, CR18, CR19, CR2
  6. I don't have an answer for your rifa cap question, but as far as the general capacitor replacement, I would strongly recommend watching @JDW youtube video on recapping the 128k - Plus analog board: (43) Macintosh 128K~Plus Analog Board Recapping Walkthrough - YouTube He talks a lot about the analog board and the parts, it's more than just a "how to replace a capacitor" video. Definitely worth a full watch. If you click the "show more" button, there is a lot of additional info there, including a list to a spreadsheet showing a list of capacitors: https://bit.ly/3diHUUG There are
  7. Thanks, good to know. I'll have a scope in a couple days. I've never used one before, I'll have a bit of guidance from a friend but nothing Mac-specific.
  8. I'll take a look at the connections AB to LB next time I have the board out, yes checked at the floppy port. Thanks!
  9. Has anyone ever found schematics for the early Classic II logic board? The Bomarc collection has schematics for the 820-0401-B board, but I haven't been able to find one for the earlier board. I don't recall if is called 820-0401-A, or just 820-0401. This is the version with 4 ROM chips rather than 2.
  10. I have a non-functional Classic II I picked up recently. When I bought it, when I powered it up all that happened is the fan came on, no other signs of life. I opened it up and found the capacitors on the analog board were leaking badly. I recapped the analog board and fired it up, and got a checkerboard screen, once. After that when I powered it on I once again had nothing - just the fan, nothing else. I re-seated the RAM and ROMs, no change. The electrolytic capacitors on the logic board showed signs of leakage so I ran the board through the dishwasher twice, warm water, no detergent.
  11. I finally broke down and bought the Floppy Emu today. I'd been thinking about it for a while, but now that I have 3 working machines I figured it would be nice to actually get software on them. My SE has a working hard drive, but that could change at any moment. Since I have a 512k and now at 128k it makes sense to get the Floppy Emu since the SCSI2SD won't work with either. The SCSI2SD seems like a nice setup to leave installed permanently in a single machine. I may end up doing that for one of my other machines in the future, but the Floppy Emu seems like a great gadget since you can ea
  12. Thanks! No HD-20, and there probably isn't one in the cards unless I happen to run across one. My plan is to get a Floppy Emu since I can use that with my other compact Macs as well.
  13. Diode CR5 had failed, so I replaced that along with transistor Q3 since they fail together. I tested diodes CR20 and CR21, the readings for CR20 were a bit off, I went ahead and replaced CR20 and CR21 since I had them on hand. As part of the shotgun approach I replaced the following diodes: CR1, CR15, CR18, CR19. Additionally resistor R2 was visibly burned, so I replaced that as well. There are a number of parts that Larry Pina suggests be upgraded on these boards. Based on your post count I suspect you're familiar with Larry's books - Dead Mac Scrolls, and Macintosh Repair &am
  14. A couple months ago I picked up a non-operating 128k, it only made a ticking noise when powered on. I started doing a bunch of searching online and ran across the YouTube videos put together by forum member @JDW, many of you are probably familiar with him as he is a frequent contributor. I reached out to James directly and he ended up helping enormously with the revival of this machine. We did a bunch of troubleshooting of individual components, and swapping components with my 512k to check parts that could not easily be tested individually. We made multiple rounds of semi-progress, and af
  15. That's cool, I grew up with 680x0 Macs, for some reason I've always had a soft spot for other 680x0 machines, especially Amigas. I'd still like to get an Amiga 1000 some day just for fun.
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