MicroMac 68040 LC575 Logic Board Upgrade

Updated: June 04, 1998
HARDWARE QUESTIONS
Q: On which Mac model can I install the LC575 logic board?
Q: Can I just replace my logic board with a LC575 logic board?
Q: How about VRAM (Video RAM)? Can I use the same VRAM I have in my current Mac?
Q: How do I identify the size of the VRAM installed in my Mac?
Q: Can I use the RAM I have installed in my old logic board?
Q: What is the maximum amount of RAM I can have with the LC575?
Q: I have 36MB installed on my LC575 logic board but the System takes over 30MB of it and there is only about 8 MB free. What is wrong?
Q: Are there other upgrades available for my MicroMac 68040 LC575 Logic Board Upgrade?
Q: Are there any additional requirements for installing Mac OS 7.5 - Mac OS 8.0?
Q: What does it mean 66/33MHz or 80/40MHz?
Q: I have a FPU upgrade on my Color Classic, can I use this FPU on the LC575?
Q: There used to be a PPC accelerator for the LC575, can I use it on this upgrade?

SOFTWARE QUESTIONS
Q: Can I just replace my current logic board with the LC575 logic board or do I need a certain minimum System software?
Q: Can I install Mac OS 8?
Q: Are there any additional requirements for installing Mac OS 7.5 - Mac OS 8.0?
Q: Whenever I try to install my System, I get a message "this Macintosh is not recognized." What can I do?
Q: Am I now able to run any software which requires a 68040 processor?
Q: What if my software requires the "CFM-68K Runtime Enabler"?
Q: Since I installed the new LC575 logic board I cannot print. What's wrong?


Q: I'm convinced, yes I want to get this upgrade, what do I have to do?

DID YOU MISS YOUR QUESTION??
Please feel free to use our FAQ submission form


HARDWARE QUESTIONS


Q: On which Mac model can I install the LC575 logic board?

A: The following Mac models have the same logic board factor as the LC575 and therefore the LC575 will fit in these models:
Color Classic, Color Classic II, Mac TV, Performa 275, Performa 520, Performa 550, Performa 575


Q: Can I just replace my logic board with a LC575 logic board?

A: Yes, but make sure you meet the minimum system software requirements. Otherwise you end up going back to your old logic board and install the System software for the LC575. (see software section for minimum system software).
If you upgraded from a Color Classic, you also need the new back panel. Since the ports on the CC are different then on the LC575. (e.g. the CC has 2 ADB vs. the LC575 has only one)


Q: How about VRAM (Video RAM)? Can I use the same VRAM I have in my current Mac?

A: Yes you can, however you also need a second VRAM SIMM of the same size. The LC575 requires two VRAM SIMMs. There are 2 sockets for VRAM on the right side see our logic board picture. You must install two VRAM SIMMs of the same size into the two sockets in order for the VRAM to function correctly. If you currently have a 512KB VRAM SIMM installed in your Mac, you must get a second 512KB VRAM SIMM in order for the video to work on the LC575 logic board upgrade.
If you get the 80/40MHz upgraded LC575 logic board, you need VRAM 70ns or faster, otherwise you end up with a black screen. The speed of the VRAM SIMM is printed on each chip, e.g. partnumbers ending in "-10" means 100ns and are too slow, "-8" or "-80" means 80ns and are fast enough for the 66/33MHz version fo the LC575, but the 80/40MHz version would need chips with partnumbers ending in "-70" or "-60".


Q: How do I identify the size of the VRAM installed in my Mac?

A: Find your Mac model in the Mac Specs and look for Video configuration.


Q: Can I use the RAM I have installed in my old logic board?

A: Yes. Unless you are a Color Classic owner, the CC uses 30-pin SIMMs and the LC575 uses a 72-pin SIMM.


Q: What is the maximum amount of RAM I can have with the LC575?

A: The maximum amount of RAM is 68MB. That's right it is not 36MB as Apple makes you believe. We have introduced the BigSIMM™. The BigSIMM™ gives your LC575 a total of 68MB.


Q: I have 36MB installed on my LC575 logic board but the System takes over 30MB of it and there is only about 8 MB free. What is wrong?

A: Verify whether you have 32-bit addressing turned ON in the Memory Control Panel. It is probably turned off since the new LC575 logic board has the default settings in PRAM. You will also probably need to reset the Date & Time, Printer, Mouse speed, etc.

Q: Are there other upgrades available for my MicroMac 68040 LC575 Logic Board Upgrade?


A: Yes. MicroMac has several upgrade options available:

• If you have the LC575 logic board without an FPU you can upgrade it with one.
• If you have the 66/33MHz model of the MicroMac 68040 LC575 Logic Board Upgrade you can upgrade it to the 80/40MHz version.
• Go even beyond the "Apple limit" of 36MB to 68MB with our BigSIMM™

To receive additional information on these upgrades, please contact MicroMac at 800-600-6227 or 949-362-1000 or view this model on our Mac Specs Data Base


Q: Are there any additional requirements for installing Mac OS 7.5 - Mac OS 8.0?

A: No, the LC575 is all you need to get started with OS8


Q: What does it mean 66/33MHz or 80/40MHz?

A: This is the frequency of your computer, like the RPM of your car, the faster the better. However it also depends on the CPU like it makes a different in which gear you are in. With the introduction of the 68040 processor there came the distinction between the CPU and the BUS speed. The CPU speed is always twice the BUS speed on a 68040 processor. Meaning 66/33MHz means 66MHz CPU speed and 33MHz BUS speed. HOWEVER, most of the software do not report the CPU speed, instead they report the BUS speed if they recognize a 68040 processor. Other with PowerPC processors they have a variable relation between the CPU and BUS speed, like a 150MHz 604 PowerPC runs at 150MHz, but the BUS runs at 50MHz. That means the ratio between the CPU and BUS is 3:1. Or a 200MHz 604e can have a ratio of 4:1 or 5:1, which means the BUS runs at 50MHz or 40MHz.


Q: I have a FPU upgrade on my Color Classic, can I use this FPU on the LC575?

A: No. The FPU for the Color Classic is for a 68030 Processor. The FPU for the 68040 is built in to the 68040.


Q: There used to be a PPC accelerator for the LC575, can I use it on this upgrade?

A: Yes, this LC575 logic board upgrade gives you a regular LC575. The problem you might have getting one of those PPC cards. Also these cards were not tested on the 80/40MHz LC575.



SOFTWARE QUESTIONS


Q: Can I just replace my current logic board with the LC575 logic board or do I need a certain minimum System software?


A: The LC575 needs System 7.1 with System Enabler 065. If you have 7.5 or later you should be fine. If you are using System 7.1, we recommend that you reinstall System 7.1 prior to installing the LC575 logic board. When you reinstall the software from the installer program do it as "customized" and select "for any supported Macintosh". We also supply the enabler on a floppy together with the LC575


Q: Can I install Mac OS 8?

A: Yes. See next answer for details


Q: Are there any additional requirements for installing Mac OS 7.5 - Mac OS 8.0?

A: No and Yes. If you have the 66/33MHz version of the LC575 logic board you can install Mac OS 7.5 - 8.0 from the Mac OS Install disks or CD-ROM disc without any additional requirements.
However if you have the 80/40MHz version of the LC575 logic board, Mac OS 7.5 - 8.0 does not recognize the Gestalt number (Machine 'mach' ID code) of the logic board due to the upgraded 80/40MHz processor. To install the System software you need to perform an additional step prior to installing the new Mac OS software.

How to Install Mac OS 7.5 - Mac OS 8 on the 80/40MHz LC575 Model ONLY:

• Either you can install the Mac OS software by taking the hard drive you plan to place the System software onto and installing it into a Mac that is recognized by the Mac OS Installer (such as a Quadra, Centris or PowerPC-based Mac). After the installer program launches, select "Custom Install" as the installation you wish to perform (not "Easy Install") and select the installation for "any supported Macintosh". After the installation is complete, return the hard drive to your LC575 logic board upgrade.

• Or you can simply use a Freeware program like "MachID Wannabe" (available to download from the MicroMac Web site) and fool the Mac OS Installer by changing the Gestalt number of the 80/40MHz LC575 logic board to Gestalt 92 (the Gestalt number for a LC575 with 66/33MHz 68040 processor.) Changing the Gestalt number, however, does not influence the speed of the upgraded 80/40MHz 68040 processor. Changing the Gestalt number merely tricks the Mac OS Installer into recognizing your Mac model since the original LC575 produced by Apple were only 66/33MHz 68040-based Macs.

Here is how to install Mac OS 7.5 - 8.0, on the 80/40MHz LC575 logic board:

1. Download the MachID Wannabe Control Panel from the MicroMac Web site.
2. Install the control panel into your Control Panel Folder (inside your current System Folder on your
   hard drive) prior to installing Mac OS 7.5 - 8.0.
3. Restart your Macintosh.
4. Open the MachID Wannabe Control Panel. It should appear as follows:
   
   
   
   
5. Type in 92 as the Machine 'mach' ID (Gestalt number).
6. Close the Control panel. Do not select the small [Reset...] Button. This button is used only if you wish to reset your Mac back to its original Gestalt number.
7. Restart your Macintosh.
8. Install the System software from the Mac OS Install disks or CD-ROM disc (do not boot from those CD or disks).

Q: Whenever I try to install my System, I get a message "this Macintosh is not recognized." What can I do?

A: You probably booted from the installer disk. See the answer above for "Are there any additional requirements for installing Mac OS 7.5 - Mac OS 8.0?"

Q: Am I now able to run any software which requires a 68040 processor?

A: Yes. Unlike a 68040 accelerator upgrade where not all 68040 software will install and run, the LC575 logic board upgrade provides the necessary ROM and logic board information that some 68040 software require before installing onto your system.


Q: What if my software requires the "CFM-68K Runtime Enabler"?

A: The CFM-68K RunTime Enabler is required by some applications to launch properly (an example is America Online 3.0). This extension should be made available to your System software (Mac OS 7.5 - 8.0) if you installed the System software as "Custom Install" (not "Easy Install") under the installation "for any supported Macintosh". (If the System software is installed correctly, the CFM-68K RunTime Enabler will be located in the Extension Folder of your System Folder) .


Q: Since I installed the new LC575 logic board I cannot print. What's wrong?

A: The new logic board does not have the printer information made available to it in its PRAM. To have the logic board identify your printer, select your printer in the Chooser again (the Chooser is located under the Apple Menu). You will probably need to also reset the Date & Time, Mouse speed and Memory Addressing settings from their respective Control Panels (located inside the Control Panels Folder inside the System Folder).


Q: I'm convinced, yes I want to get this upgrade, what do I have to do?

A: To place the order, use this form (there is also a phone number on this form to call).
At the time you place the order you will be given a RMA number for you logic board, which you send back to us after the LC575 is completely working. This RMA number also appears on your invoice. However, If you fail to return your logic board after a reasonable time, We'll charge you for your logic board. Otherwise we can not keep the lower price for this upgrade.


If you have further questions or find these FAQs need further updating, please email us at qaupdate@micromac.com or use the online form.


You my also use place your question on some mailing lists.