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MrFahrenheit

6502
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  • Interests
    Vintage System 6, 7.x, HyperCard, older vintage hardware such as Jaz and Zip drives, Apple A/UX, Mac OS X Server, Debian Linux, Calculating Pi to insane digits.

    Recently been recapping all of my vintage hardware.

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  1. MrFahrenheit

    Nearly dead sound on my Performa 550

    I bought a 550 board in a huge lot of items. I recapped it and when I tried it I had no sound as well. The board was clean before recapping. From what I’ve found, sound chips in the color Classic/color Classic II, LC520/550 boards are notorious for dying. Bruce from recap a Mac in Australia has mentioned in his videos he has a drawer full of brand new stock sound chips for these machines, because it’s such a pandemic of failure.
  2. MrFahrenheit

    New to this board - Macintosh II & IIfx

    Awesome! I picked up a IIfx in March and recapped it in June or July. I haven’t used any special filter of terminator on my IIfx. Strangely enough the SCSI on mine works just fine without it. Not sure why. Externally I used an Iomega Zip and Jaz drive, with the Jaz drive being at the end of the chain and I used an active terminator on it instead of the Jaz onboard one. I also installed a new internal hard drive without any filter and it ran fine too. I don’t get it. In case I needed it, I recently bought a black IIfx terminator. I identified it in a bulk cables lot and asked the seller to verify the part number and it was the one. So I bought the entire lot just for the one terminator. I can check and let you know the exact part number because there are non-IIfx black terminators that aren’t the same out there.
  3. MrFahrenheit

    SE/30 - Horizontal line on Startup

    The biggest differences between tantalum caps and others is they have different resistance ratings, and they have a 'wobble' or frequency. I've found ones in the 100khz range are fine. Also, the lower the resistance the better. That's about it. If tantalum were that big of a problem, Apple themselves wouldn't have used them. But they did. There are a lot of machines that use both electrolytic and tantalum caps (different ratings for each), and the IIfx has spots for both electrolytic and tantalum caps (one of the only boards I know that is like this). On both of my IIfx machines, there were electrolytic beside an empty tantalum pad on about 3-4 of the locations. I successfully recapped with all tantalum caps. I have recapped over 70 Macs using tantalum caps and I have not experienced anything bad or wrong, after I figured out which resistance rating and khz frequency to use. YMMV
  4. MrFahrenheit

    SE/30 - Horizontal line on Startup

    I had this same issue and I sent my boards to a fellow 68kmla member who had more SE/30 experience than I did. The QA signal line from UF8 was broken before the via that takes it to UG6. So he put in a bodge wire and it booted.
  5. MrFahrenheit

    Macintosh II Battery Holder Board

    My Mac II machine has one of these boards on it. I was surprised when I popped the cover and saw it.
  6. The problem with higher voltage 47uf tantalum caps is they have different resistance ratings and their frequency “wobble” is different. This could cause issues. The Quadra 610 uses 10x 47uf 16v caps and nothing else, so I had wanted to see how the higher rated caps would affect it. I bought some 47uf 20v and 25v caps to redo a Quadra and after recap I found that turning it on did work, but the machine overall didn’t. SCSI would not work, mouse did but cursor operation was about 1/4 normal speed. Flashing disk question mark was 4x slower than normal. I removed all of the higher rated caps and replaced with the standard 47uf 16v 900mohm 100khz caps and it booted right up just fine. I had replaced a few caps on one Mac with higher rated caps, leaving the rest the same, and found the same issue. The caps I had done on that one were for the SCSI bus, and I found SCSI to not work (the 25v caps I bought had 3ohm resistance I think). I believe this higher resistance affects some parts of the Mac differently than other parts. I do prefer tantalum caps but this is the reason buying them is not as easy as just placing an order. Tantalum caps have these issues more so than other types of caps, and matching up proper specs can be difficult. I have no idea what Apple used for their 47uf 16v tantalum caps (resistance, wobble, etc), and I would love to figure that out.
  7. It’s not Mac related but I was working on connecting my commodore 1541 disk drive from 1987 to my 2019 windows 10 PC.
  8. It's a 16v cap, and the rail is 12v, so I'd say it should be fine.
  9. Possible but I’ve had two that failed at C1 that were factory caps. One was repaired by Apple at one point in the far far past. I think this cap undergoes a lot of stress for some reason, but again I don’t have a lot of IIfx experience. I have two machines and both had similar issues. Both were original factory tantalum caps. I would say this is good evidence to recap any and all Macs including those with factory tantalum caps. You never know when they’ll fail.
  10. I'm not experienced enough with the IIfx to know the answer. That could very well be. Both of my IIfx had issues with C1.
  11. To be honest I would wait and recap the whole board. I had a similar issue with a IIfx I bought earlier this summer. Interesting that mine was also C1. I ended up soldering all new tantalum caps and for C1 I instead used the other solder pads. You may want to do the same.
  12. MrFahrenheit

    Mr Fahrenheit’s conquests

  13. MrFahrenheit

    Mr Fahrenheit’s conquests

  14. MrFahrenheit

    Mr Fahrenheit’s conquests

  15. MrFahrenheit

    Mr Fahrenheit’s conquests

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