So, I just picked up an LC 580 (amongst other things) from a guy on Facebook Marketplace. He was not a computer guy and just found them in a home he was renovating, so not the original owner. Anyway, I opened up the LC today to upgrade RAM, swap out the struggling IDE hard drive and generally inspect everything. Outside of brittle plastic falling apart on me as I worked, I noticed that the motherboard looked different from the Apple manual I was following online for an "LC 580". After some confusion, I saw that I had a PowerPC 603e motherboard (820-0751 A) from a 5300/100 LC in there! Sure enough, the profiler shows the model as a "PM 5200/5300" and the processor as "PowerPC 603e running at 100MHz". It took the full 64MB of RAM (when the 580 is only supposed to handle 48) and it booted up to Mac OS 9.1 (which was on the HDD I had installed, planning for it not to read), much to my surprise.
My question is, even though this is a nice and unexpected upgrade, will it hold up over time? I read somewhere that a power mod needed to happen to make this work too. I assume whoever had this before me did that because it all seems to work (albeit, slowly) just fine. I think I'll go with Mac OS 8.1 or 8.5 eventually. Anyway, was this a common swap back in the day and can I use it as a "PM5300" as long as I don't use the PCI slot?
My question is, even though this is a nice and unexpected upgrade, will it hold up over time? I read somewhere that a power mod needed to happen to make this work too. I assume whoever had this before me did that because it all seems to work (albeit, slowly) just fine. I think I'll go with Mac OS 8.1 or 8.5 eventually. Anyway, was this a common swap back in the day and can I use it as a "PM5300" as long as I don't use the PCI slot?