512K to 512Ke upgrade

[brayne]

Hi all,

I recently purchased an untested Mac 512K on eBay, and it arrived today. It was dead, but I replaced a fried resistor, and it's working now.

To my surprise, when I placed an 800K, 6.0.5 system disk in it (just to see if the drive motors were working), it booted up! So I can only assume this has had the 512Ke upgrade at some stage in its life.

Quick question for anyone who might be able to answer. Is there a way I can identify if this is the original logic board with a 512Ke ROM upgrade, or whether someone has replaced the whole logic board with one from a 512Ke? Or is there no identifiable difference between the two logic boards (other than the ROMs)?

One other question. Does the fact that this is an upgraded 512K devalue it at all? I have zero intentions of selling it, but I'm just curious if it's an undesirable upgrade from a vintage Mac valuation perspective.

Thanks in advance,

Bruce 

 

[Elfen]

Read the date code on the ROMs compared to the rest of the board. date codes with XX84 to XX86 should be the older 512K ROMs and XX87 to XX89 should be 512Ke/Plus ROMs.

No, it should not devalue the machine in any way. It just makes it a 512Ke. Chances are, your Mac was either upgraded or repaired by Apple at one time or another (with a logic board swap), and that it. As long as it was done by Apple or an Apple Authorized dealer. Many 512K Macs under went this."operation" for one reason or another in the 80s and 90s, yours is one of them. Nothing more.

EDIT: If the date codes on the ROMs are at around the same time as the rest of the chips on the board, then the logic board was swapped out. If the date codes differ by a year or more then the ROMs were swapped out.

 

[brayne]

Thanks Elfen, that's excellent info.

The board definitely looks like an original 512K...

...and the ROMs are dated 1985, so I guess that means ROM upgrade.

Thanks again!

Bruce

 

[Elfen]

Congrats! Looks like you got a ROM Upgraded board. If you got the 800K drives in it, looks like you got an upgraded machine (800K drives w/ROMs from Apple). Usually but not always, the 512K Mac came with a 400K Drive. Over time, people tend to upgrade them with the 800K drives.

 

[brayne]

I have to say, I'm pretty ecstatic about picking this up for so cheap. I've been on the lookout for an original 128K or 512K Mac for some time. They don't come up that often here in Australia.