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The Macintosh LC, if not Apples most crippled computer must be up in their top 5. The machine is purposefully held back in so many ways that performance is severely impacted yet it was still successful and is still an enduring member of the Macintosh family.

The LC in Apples 1990 Macintosh LC stands for “Low Cost” or “Low Cost Color” so one wouldn’t be shocked to to find that the machine is hindered performance wise. This was Apples stab at making a low cost color Macintosh for the family and the educational market.

The first thing one notices about the LC is its extremely thin and light case. This case became known as the “Pizza Box” case due to its similarity to the shape of a Pizza Box. The case is remarkably small and light and despite being all plastic it holds up as there are only two fairly sturdy plastic tabs on the rear that secure the top of the case down. The LC sports one or rarely two 1.44mb floppy drives. The two drive versions were not very popular but you can see on the left where another floppy drive could be placed. Usually as with this model that space was occupied by a 30 to 80GB 50 pin SCSI hard drive.

Looking at the rear of the LC was have a standard connector for a power cable as well as a switch. The LC does not support soft power on from the keyboard so powering on and off is done via the rear switch. Next to that we have a 15 pin video port for the built in video, an apple printer, modem port an external SCSI port a ADB port for keyboard and mouse and finally two audio jacks for speakers and mic.

Here is the inside with the top cover removed and we can see the motherboard is very small and compact. This machine when I got it had the hard drive removed but you can see where it would be mounted. between the two drive bays we have a speaker and a small fan. The LC also uses a proprietary small form factor power supply which if yours dies can be an issue to replace.

1) CPU – The Macintosh LC is controlled by a Motorola 68020 CPU running at 16mhz. The crippling factor here though is that we have a 32-bit CPU running on a motherboard with a 16-bit data bus thus severally hindering the performance of the CPU. One example of the bottleneck this created is the Macintosh II which used the same CPU yet ran on a 32-bit motherboard. This computer is almost twice as fast or up to 40% faster then the LC despite having the same clocked CPU. This performance gap is due mainly to the restrictive data bus of the LC. The LC also lacked a MMU (Memory Management Unit) for virtual memory or ability to add one thus limiting the memory.

2) RAM – RAM is another area that the LC is a bit limited. The LC comes with 2MB of RAM soldered onto the motherboard with the option to add another 8MB via two 30 pin SIMM slots for a total of 10MB of memory. This limit is placed by the memory chipset so even placing larger RAM sticks into the sockets still results in a limit of 10MB. This amount of memory, though usable, was fairly small even by the standards of 1990.

3) Video – The LC came with video built into the motherboard as well as 256kb of VRAM upgradable to 512kb via a VRAM socket next to the two 30 pin RAM sockets. At stock configuration the LC supported 512×384 pixels at 8-bit color while upgrading to 512kb gave the ability to display that same resolution at 16-bit color or 640×480 at 8-bit. The problem was the LC was mainly meant to display at the 512×386 resolution and even had a special 12″ RGB monitor which had its resolution fixed to 512×386. This monitor fits perfectly on top of the case of the LC, LC II and LC III. Many programs at the time expected 640×480 so when displayed on the 12″ RGB monitor at 512×386 a number of programs displayed incorrectly.

The LC is also notoriously picky about what monitors it will work with. neither my Sony G420, Gateway T17LC-8 CRT monitor nor my Samsung Syncmaster 171n LCD monitor would work with the LC when using a mac to PC adapter. This incompatibility continued when attempting to use a VGA to S-video converter as it produced a rolling and unstable image on my Sony KV-32FV310. usually the error was an “Out of Sync” error as the LC seems to output at a 25khz frequency many monitors just will not accept. I finally had to use a NEC PG-2740 professional monitor to get an image from this machine or the LCII I also have.

It is supposedly possible to modify the Apple 12″ RGB monitor to run at 640×480 but it likely takes some experience with soldering and working with CRT monitors and not for the novice.

4) LC PDS slot – Expandability on the LC was pretty meager and it only sported one specialized LC PDS (processor direct slot). This slot was mostly intended for the Apple IIe compatibility card which granted high compatibility with the huge Apple IIe backlog of games and programs but other cards such as accelerators and video cards were produced as well.

5) PRAM battery – for saving settings

6) Floppy connectors – The original LC had two floppy connectors for connecting one or two 1.44mb floppy drives. Note that these are special drives that receive power via the floppy cable and also use a auto eject mechanism. The dual floppy versions of the LC are pretty rare as this was not a popular option.

7) 50 pin SCSI connector for connecting a SCSI hard drive.

8) PSU connector

So lets go over and list the issues that crippled this machine.

1 – A 32-bit CPU on a 16-bit motherboard severely hampering the performance of the LCs 16mhz 68020 CPU.

2 – An imposed limit of 10MB of RAM regardless of the size of the RAM stick(s) installed.

3 – complete lack of a MMU or FPU or the ability to easily add one.

4 – Difficulty getting the LC to run with any monitor outside of the 12″ RGB  fixed resolution 512×386 monitor it was intended to be paired with or period Apple monitors.

Considering that Apple was trying to create a low cost machine at an affordable price one wouldn’t be to surprised at the cost cutting done to the LC and the limitations thus created. One plus I could give the LC is that it is extremely lite and the Mac itself is easy to transport and setup. The case is also pretty durable for being all plastic and the tabs seem to hold up fairly well. That said for the modern retro gamer looking for an early 90’s Macintosh I would stay away from the LC for anything other then pure collecting. They are fairly cheap even on eBay as well as easy to find but there are far better options such as the various models of the Macintosh II or the LC III (which we will get to). I should note that the LC in this article currently is none functional due to leaking capacitors which is a common issue on old PC’s and especially these 80’s and early 90’s Macs. Apple did in fact attempt to correct the issues that limited the LC though it wouldn’t be until the third iteration that they more or less got it right.

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  1. These were common machines in my later public school years. The cool thing was the IIe emulation card, which is essentially a full Apple IIe on a card. It is cool that you have the matching monitor…I have a number of LC series machines I have collected, but no monitor yet. I would highly recommend removing that red PRAM battery – that particular brand seems to be more inclined to leak and destroy the machine than other brands. Note that you will need a good battery for the machine to work. I would also get those capacitors removed and the goo cleaned up, even if you don’t replace them right away…it is corrosive and will damage the board as well. Best trick I’ve found is to use a pair of pliers…squeeze, push down, and turn…legs will snap right off. Yeah, I know, sounds like the worst possible way to do it, but I’ve done more damage trying to de-solder than I have with the twist method. Now if there is board damage already, it might be a bad idea, but a solid board should be fine. I have heard a number of people use that method. I also opted for MLCC capacitors for replacement…should last much longer, and are smaller and easier to solder in place. If it won’t power on, there are also a couple of through-hole capacitors in the power supply that commonly go bad and are pretty easy to replace as well.

    • Unfortunately this machine is dead and so is the monitor. I’m pretty sure this machine is dead due to the caps leaking everywhere. The monitor on the other hand powers on the image has suffered vertical collapse. so you can sort of see an image but it is unusable. I do have an LC II and LC III though that I’m going to do articles on coming up and those machines are fully working.

        • Wesley
        • Posted September 29, 2017 at 18:51
        • Permalink

        Unless there are damaged traces, new capacitors will likely fix it right up…I see where someone replaced one with a through-hole capacitor (bad idea in my book), but I’m sure they are all shot. If it won’t even power on, that is the power supply capacitors… I read something not long ago somewhere and someone commented on what the issue was with the monitor that you describe, but I don’t remember where I read about it. Probably repairable as well. I found one at a recycling place one time, but it didn’t show signs of powering up at all (other than the power LED), so I left it behind… I imagine your LCII (and probably III too) having leaking capacitors as well…pretty much just a matter of time with Macs of that era. 😦 I have several here I need to replace capacitors in as well… If you need help or guidance to work on any of the, I’d be happy to try to help. I have enjoyed keeping up with your blog!

      • My issue is I’m pretty terrible at soldering, even worse with surface mount stuff. I still have the CRT around so i may attempt to fix it. I have a YouTube companion video coming with some footage of what it’s doing. The caps on the LC II and III are definitely leaky so your right, only a matter of time. I’m glad you like the blog and I’ll keep you in mind if any questions pop up, thanks!

  2. As an original buyer of an Mac LC in February 1991 I stand in defense of my first own Macintosh. Imagine the situation in 1990/91. Before the LC most Mac users had access only to 68000-based Macs. But every LC runs circles around a SE, Plus or original Classic. Compare it yourself or look up the benchmarks at Low End Mac website. LC performance is pretty near to a Mac II – with the exception of floating point operations, which are not widely used. It has the same processor, the MC 68020 at the same speed as a Mac II (even the same speed as the enhanced models IIx, IIcx and SE/30). This is twice the clock rate of any classic Mac! This makes a big -real world- performance difference.

    Also, before the LC color capability was only offered in the Mac II-class. These were machines with a price tag similar to a moderately sized car, hence out of reach for private use. When the LC became available you got color or at least a grayscale Mac, both a big improvement over the monochrome (1-bit color-depth) of the classic Macs. (The Color Classic came out 2,5 years _after_ the LC, using the same 32/16-bit architecture, now really outdated).

    • I don’t think the LC is a “bad” machine just crippled compared to what it could of been and although I think it may of been a good budget buy at the time as a retro gamer now there’s much better choices. Of course these corner cutting measures would of been expected for a low cost system at the time. I do very much appreciate the small and light case.

      As a kid I think I probably would of wanted this machine over virtually all of the compact macs just on the fact it was color alone though I find the LC and LC II’s pickyness about what monitors will sync to them very inconvenient.

      The LC does have the same processor and 16mhz speed as the Macintosh II it does not run at the same speed. All my research puts it at 30%-40% slower then a Macintosh II with the same CPU due to the 16/32 bit architecture.

  3. I agree. There is a 30-40% speed deficit (and a four-fold price difference) compared to a Mac II. What I wanted to say was: The _clock-rate_ is the same as in a Mac II or even in the newer IIx, IIcx or SE/30.

    Monitor problems: I never experienced any. Did you check configuration of the sense-pins in the LC’s display connector? The VGA-adapter should take care of. Many adapters have dip-switches for signaling the demanded resolution and refresh rate to the sense-pins. The adapter’s data-sheet should list possible settings. I have seen adapters with four, six or no dip-switches at all (hard-wired for a specific resolution).

    Probably, I never had problems, because my LC was always set to 640×480, which any VGA or multisync monitor should be able of, and not the LC’s lower resolution at 512×384. I originally bought Apple’s 12″ b/w display, offering the advantage of displaying the full 640×480 pixels at half the cost of the 12″ color monitor, sacrifiing color for grayscale and higher resolution. It solved also a performance problem in System 7’s slower Finder (slower than System 6’s). This LC’s 256k video-RAM allowed only 16 shades of gray at 640×480, which is actually enough for a decent result. Programs like JPEGview did a great job in dithering pictures for a good display quality even with 4-bit grayscale. After upgrading video-RAM to 512 kB, the drawing of the now 8-bit deep display became annoyingly slower. An effect caused by the narrow 16-bit data bus.

    • Yep, I used 2 different adapters, one without DIP switches and one with. on the one with I tried all the resolutions and I couldn’t get it to display. Using the same adapters and monitors my LC III had no issues. on all the monitors I get a “out of range” error and it lists something like 25khz. Since my actual 12″ RGB monitor has major issues the only other monitor I got the LC II working on was a huge 27 inch NEC professional multisync.

  4. I still think that your problems are caused by the LC’s attempt to display Apple’s odd 512×384-resolution, hinted by the 25kHz (should be exactly 24,48 kHz) displayed horizontal frequency. Look up the sense pin configurations and measure what the dip switches of your adapter are actually doing:
    Apple’s original Tech Note:

    However, if your LC does default to 640×480 instead, a PRAM-reset after power on may help. Nevertheless the easiest way to success is an early 1990’s plain 14″ VGA-display (640×480 only) with an adapter set to this resolution. That is what I have used in the mid 90s, after I got a decent Philips-VGA-monitor and I had abandoned my b/w Apple.

    With only 256kB of video-RAM you will only get 4-bit color on VGA. Since most apps of that time did include 1-, 4- and 8-bit icons at least your Finder experience will be decent. Choose a desktop pattern that only uses colors from the default 16-color-palette. Any other will mess up your color lookup table, so the 4-bit icons will no longer be displayed correctly and maybe fall back to 1-bit versions.

    I am quite sure the LCIII defaults to standard VGA resolution which helps with modern multisync displays. It also supports Apple’s odd 832×624 standard. At 8-bit color it make use of nearly all of the 512k video RAM while maintaining a 4:3 aspect ratio. Especially on lower end Apple monitors and cheaper Performa video cards this setting resulted in a sharper screen than the popular 1024×768. I even bought a used 1991 Apple 16″ Color Display from my university, and used it with my Performa 475, and later with my Powerbook 5300, and sold it together with a PowerMac 6100 in 2000. Btw, the 6100 and the 16″ display were a perfect fit. Together they had the nice and serious 1990s workstation look I had admired when I was allowed to use one of the Sun or HP workstations in University.

    • I have an LC III and it fired right up on my Sony G420 monitor. I wish I could find some more older apple monitors locally. been looking for a apple color composite for my IIe for awhile now. I’ll try playing around with my LC II more and see if I can coax it to display but since I acquired an LC III its become a pretty low priority.

    • Well, I did manage to get the LC II working on my G420 monitor with a DIP switch adapter set to 640 x 480 @ 67hrtz. Image is off center but it displays.

One Trackback/Pingback

  1. By Macintosh LC III | ancientelectronics on 09 Jan 2018 at 2:59 pm

    […] previous articles we covered both the nearly identical LC and the LC II, both of which were early attempts to bring an affordable color Macintosh to the […]

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