Rom Question

[macfan2350]

Hey guys, I just have a simple question to ask.

I have a Macintosh 128k with what I think to be a 512k upgrade board. It even says 512k on a little sticker on the board. However, it is missing the Roms to it. It just displays a checkerboard. My question to you guys is, what roms should I purchase? 512k roms or 128k roms. Thanks again, any help is welcome. 

 

[macfan2350]

It has a model of M0001, and a add on board model of DIGICO D-1061

 

[Crutch]

The 128k and original “unenhanced” 512k Mac both came with the same ROMs — which were 64k in size.

With the introduction of the Mac Plus, ROMs with 128k of data were introduced.  These are generally referred to as the “128k ROMs”.  They are NOT the ROMs that would have come with a 128k Mac, so it’s easy to get confused!  These 128k ROMs were also included with the 512k Enhanced, and with any upgrade kits to upgrade from a 128k or original 512k to a Plus or 512k Enhanced.

So, your question should be, do you want the 64k ROMs or the 128k ROMs?  The answer is ... it depends.

Some of us like to run an authentic, unupgraded vintage-1984 Macintosh.  If you want that experience, you’ll want the 64k ROMs.  @Dog Cow has a wonderful blog about (mostly) unenhanced 512k Macs and all the things you can do within the confines of a legit, non-upgraded ‘84-‘85 machine.  When I decided to get a 512k Mac I specifically wanted the 64k ROMs.

The 128k ROMs are generally needed if you want to work with 800k disks and include lots of new functionality, as well as various patches and optimizations that, I am told, result in faster performance generally.  They also seem to be more widely available and cheaper.

 

[macfan2350]

Hey! thanks for the prompt reply! Lots of information here! I appreciate it!

Personally, I don't really care for a 100% authentic experience, as I have already opened and worked on the machine. However, I have just 2 questions still. Those 2 being, are Macintosh Plus to 128k (including 512 and 512ke) roms interchangeable with each other? Also, if I were to buy rom chips for my particular mac, which I assume to be a 512k (if I understand you correctly), what should I look for? I'm searching on ebay if your curious. 

Thanks again!

 

[Crutch]

If you prefer functionality over vintage authenticity, grab a 128k ROM (the one that came with the Mac Plus).  That would allow direct connection of any 800k external drive, built-in HFS support and, if you want, you could swap out your internal 400k drive for an 800k drive later on.

I have bought a pair of these before — the seller is legit and the chips work fine.  https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F153388322552

 

[macfan2350]

Thank you so much for the very insightful reply. You explained things great and I learned a lot from it. I will get to ordering the rom chips and report back if I have any issues. Thanks again!

 

[dochilli]

If you know someone who has an EPROM-programmer you can burn a copy of the ROM into two 27C512 EPROMs or pin compatible EEPROMs.

ROMS are here:

https://www.nightfallcrew.com/25/04/2014/macintosh-plus-sad-face-repair/

 

[macfan2350]

Awesome! Thanks Again!