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Thread: New Mac LC II Video Posted on YouTube

  1. #1
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    Default New Mac LC II Video Posted on YouTube

    All,

    I just posted a video for #MARCHintosh, where I raided my stash and came out with an untested Mac LC II:

    https://youtu.be/RxH1aafl2hg

    This is the first video in the series. Please let me know what you think!

    - Alex

  2. #2
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    I was never really a fan of the LC or the LC II because they were such compromised designs. Apple retired the 68020 with the original Mac II only to re-introduce it with the LC less than a year later. The LC II got a 68030 at the same 16 MHz clock speed as the 68020 in the LC, and the rest of the machine is virtually identical. In order to cut costs, Apple used a 16 bit data bus on both machines, which considerably slowed both machines down, and artificially limited the RAM to 10 MB maximum, no matter if you install larger memory modules.

    Both machines had a default resolution of 512x384 in order to get 8 bit color with the 256k of video memory on the logic board. If you install a 68 pin 256k VRAM SIMM, this bumped it up to 640x480 at 8 bit color, which is almost a required upgrade because many Mac applications by this point expected 640x480 at minimum and would refuse to run otherwise, leaving these Macs stuck with older software designed for the compact Macs that ran a screen resolution of 512x342.

    The LC III and LC III+ is where things turned around, this was a clean new design that didn't make any serious compromises that drastically affected performance. The bus was a full 32 bits with a faster 25 or 33 MHz 68030 and 512k of onboard VRAM, upgradeable to 768k. I have one of these machines and it's so much nicer. There were upgrades for the LC and LC II that gave them faster CPUs, but the 16 bit bus really limits the performance increase possible.

    As for the caps, I would say replace all of them besides the fat line capacitor. I've recapped several LC style machines, including my own LC III in the last couple of years that all were suffering from leaking capacitors. The ones in the power supply are hard to see if they're leaking because it's such a compact design, but once you start pulling caps out of the board, you'll usually see wetness under the caps where the electrolyte is coming out. The same goes for the SMD caps on the logic board, the leaking usually stays mostly under the cap unless the machine is stored sideways, when it will seep out across the board.

  3. #3
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    did the 68020 based LCs employ any sort of memory management chip like the original Mac II?

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    The original Macintosh LC with a 68020 didn't have a 68841/51, so it couldn't support virtual memory. The LC II with a 68030 did support virtual memory though because the 68030 integrated a 68851 MMU on the die.

    Additionally, the LC didn't have the ability to add a 68881/68882 FPU. The LC II had solder pads for a FPU, but no socket, so it also couldn't be upgraded without soldering.

    It may be possible to make an LC PDS card with a MMU, but it isn't known if the machine could use it if it was present. There were CPU upgrade cards made for the LC and LC II. I have a MicroMac 25 MHz 68030 upgrade for those machines, which also has a 68881 FPU.

  5. #5
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    Yep, I mentioned the compromised nature of the LC II in the video. It’s not a fantastic machine, but I do indeed like the form factor. It’s also _extremely_ easy to work on, which is quite a positive.

    - Alex

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    Owing to the nature of the "pizza box" style case used for several models, you can play musical chairs with logic boards and go all the way up to a 68040 machine. Early Quadra 605s used the exact same case as the LC I - III before the newer stylized design case that looked more like PowerPC machines came out. If you could find an LC III, III+, 475 or Quadra 605 logic board, it'd be a good upgrade.

    I recently recapped a Quadra 605 for a customer and modified it to run at 33 MHz since the customer had a full 68040 to replace the stock 25 MHz 68LC040. It was a pretty nice performance boost, and way faster than even my LC III at 33 MHz.

  7. #7
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    Quote Originally Posted by GiGaBiTe View Post
    Owing to the nature of the "pizza box" style case used for several models, you can play musical chairs with logic boards and go all the way up to a 68040 machine. Early Quadra 605s used the exact same case as the LC I - III before the newer stylized design case that looked more like PowerPC machines came out. If you could find an LC III, III+, 475 or Quadra 605 logic board, it'd be a good upgrade.

    I recently recapped a Quadra 605 for a customer and modified it to run at 33 MHz since the customer had a full 68040 to replace the stock 25 MHz 68LC040. It was a pretty nice performance boost, and way faster than even my LC III at 33 MHz.
    Yep, I have performed similar modifications. My LC/Performa 578 has a full '040 installed. That machine is one of my favorite 68k Macs, due to the good performance and excellent Trinitron CRT.

    - Alex

  8. Default

    thanks for up video, that useful with me.

  9. Default

    good video, keep working.

  10. #10
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    Part two is now available:

    https://youtu.be/1m1z_zpgKqo

    Please forgive the error by my now-former sound engineer.

    - Alex

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