Source for purchasing a MC68851 PMMU for a Macintosh II

[jasa1063]

I did some checking and was able to find a reliable source for purchasing one of these. I did find one other source but it was double the cost. Here is the weblink for a company in the Netherlands.

Origineel Motorola XC68851RC16 MC68851 – Van Dijken Elektronica

www.vandijkenelektronica.nl

You cannot purchase directly from the website if you are in the United States. You need to contact them via their website contact form and arrange shipping. Total cost for me was 84 Euros or about $95. Not cheap, but at least I can now continue getting my Macintosh II upgraded.

The other source was www.IC-Components.com. The quote came back at $189. I just wanted to pass along this info in case anyone else needs to purchase one of these for their Macintosh II or Amiga with a 68020 CPU.

 

[jasa1063]

I just wanted to add I did get another quote from www.ovaga.com that came in at $120. Again a bit steep, but it is another source if someone is looking for one.

 

[Iesca]

I had managed to find one back in February 2022 on eBay for $35 before t&s, but it was the only one left at the time iirc. The seller was "eclectrons" (though they seem to have changed their name to emlieproducts). A quick search just now on ebay reveals a couple of listings for the manual, but not for the actual chip, which I'm sure was your experience as well.

 

[ObeyDaleks]

FYI, another option is to find the Daystar adapter and use the PowerCache or the Turbo040 card. This will provide the MMU upgrade as well (plus a speed boost). Although, those adapters are fairly rare.

 

[jasa1063]

FYI, another option is to find the Daystar adapter and use the PowerCache or the Turbo040 card. This will provide the MMU upgrade as well (plus a speed boost). Although, those adapters are fairly rare.

Sure you can go the 68030 route, but it is not the same as having the 68020/68851 combo, which is what I was looking for. That is unique to the entire Macintosh line of computers.

 

[Melkhior]

That is unique to the entire Macintosh line of computers.

Unique for Macintoshes, and not that common elsewhere. The 68851 was late and complex and slow and expensive, and a lot of people used other solutions, mostly custom-made MMU. For instance, Sun for the sun3 range (but sun3x were 68030), HP with some of the 300 series (at least. 9000/330 and derivatives), or Apollo with at least the DN300.

Happy you could find a 68851 and preserve that little bit of history.

 

[ObeyDaleks]

Sure you can go the 68030 route, but it is not the same as having the 68020/68851 combo, which is what I was looking for. That is unique to the entire Macintosh line of computers.

Yep, I just wanted to mention it as an alternative way of adding memory capacity (if that is the goal for someone reading this). Mine has the PMMU as well as the SuperDrive (SWIM/ROM) upgrade. But I stuck a 040 in there to make a bit more snappy. I can always return it to stock by swapping the chips.

 

[jasa1063]

Yep, I just wanted to mention it as an alternative way of adding memory capacity (if that is the goal for someone reading this). Mine has the PMMU as well as the SuperDrive (SWIM/ROM) upgrade. But I stuck a 040 in there to make a bit more snappy. I can always return it to stock by swapping the chips.

That is as really a flexible setup as you can always go back to the original configuration by just removing the accelerator.