Upgrading an
LC 475, Quadra 605

The original LC was my very first Macintosh computer back in the very early 90's. It served me well for many years but it was crippled by a fairly slow cpu and almost no memory expansion. Even the fpu or floating point unit was a plug in option.

This page is going to focus on the LC 475 and Quadra 605. Both machines are pretty much identical except for a slight modification to the bottom of the computer. The Quadra sits level on 4 feet while the LC 475 is slightly raised at the front and doesn't have feet on the four corners. Personally I kind of like the design of the 605 slightly better than the 475 but that's just me.

There really isn't a whole lot you can do easily to the motherboard of this machine. There is one PDS expansion slot which can take a network card such as the one in the photo above. There is also one 72 pin simm slot and two vram simm slots which can be upgraded to a pair of 512k simms.

This machine will take one 128 mb 72 pin simm such as the one in the photo below. Beware of chips that are too tall as I have seen chips which had two vertical rows of chips and were about double the height of the one in the photo. These particular chips work just fine in the 475 and allow you to close the lid.

There was a product on the market called the SimmVerter. It came in several styles that allowed you to put multiple strips of ram into a single slot. The is a twin slot 72 pin version which is model number 72x72 and was actually designed to fit over top of a simm in the slot in front of it.

The problem with this device even if it did work is that you cannot install the cover because the chips stick up above the lowest point of the top cover. In defense of this product, it was never designed to be used in this style of Macintosh computer! Oh and I did try installing two 128 mb 72 pin simms into this device. The Mac would not boot up.

There was another version which allowed you to install four 30 pin simms into a single 72 pin slot but with the cost of ram these days I honestly can't see any reason for doing this. But for documentation purposes I included photos of these items below.

The good news is, if you only install the one strip of memory you will have 128 mb plus the 4 mb installed on the motherboard.

The LC Quadra has a limited upgrade path. Apple did ship a PowerPC upgrade card that replaced the 68040 cpu on the motherboard but this was reported to be of little value in terms of increased speed. As with all the LC series pizzaboxes there is a processor direct or PDS slot which can take several items including a network card and that is a handy option if you are setting up a server. On a slightly different note, Asante also made an ethernet adaptor which plugged into the SCSI port and was called the EN/SC. I came in serveral sytles including a very nice small unit that was used on some of the original PowerBooks.

Here are some great pages for LC 475 owners.