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NegativeLatency

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  1. Figured it out finally, confusingly the header labeled "FAN" is not for the fan, it's for the LED, the fan connector is under that little piece of metal between the boards.
  2. I had a hard time finding one, so I made my own with some 1/2 AA battery holders, perf board, and long pin headers. Just cut your old batteries off and straighten the leads out, the pin headers fit right over them without too much fuss. Had to drill out the perf board to make the holders fit, and backed them up with some copper wire to strengthen the connection. Haven't added the cap yet, but it seems not to need it, and the original setup was just two batteries with no cap.
  3. Looks like you figured it out, but it's a 250V ~ SH 0.022 µF capacitor. Seems like mine is about to pop too, judging by the cracks. Any chance you could post a pic of where your fan and LED hook up? I'm trying to figure out where to hook up a replacement fan and LED for mine that's missing one.
  4. Does anyone have a Astec AAI3780 / Apple 699-0389 power supply with a fan and LED installed that could tell me where they connect to? I have a one that works except it's missing a fan and the connection for the LED. If you could post a pic of an intact one that would be super helpful, as this is the last stage of fixing up a Macintosh II. I tried hooking up a modern 4 pin PWM fan didn't seem to do anything, and testing the voltage of the fan connector (5v at boot, thought it was a 12v fan), and I don't see where the LED would've connected.
  5. I'm looking to do the FDHD upgrade to a Macintosh II, aside from the SWIM chip, I need some replacement ROMS, I've never burned EEPROMS before but since the ROM dumps are online it seems possible, does anyone know of a guide on how to do this? I'm not sure how to know what kind of EEPROMS to buy and how the data on them needs to be laid out. Any help or resources would be greatly appreciated.
  6. Also found this on the AppleWiki https://apple.fandom.com/wiki/Motorola_68851
  7. I think I found the answer in "Macintosh II Repair and Upgrade Secrets", my board has the HMMU Seems like that part from ebay will work?
  8. Background: I have a macintosh II that I'd like to get A/UX running on (it's partially complete, needs a hard drive and a video card) I'm not sure if the main board has a PMMU or HMMU (I suspect it has an HMMU and was wondering if anyone knew for sure) Here's a shot of the CPU, FPU and the MMU which doesn't appear to be the MC68851 chip. Follow up question, could I replace the existing MMU with a PMMU like the one on this ebay listing: https://www.ebay.com/p/556755362
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