"Greg Andrzejewski" wrote in message news:QpmdnTmhAqGYuBLdRVn-hw@comcast.com... : : > Just type in at the basic prompt: : > : > PRINT PEEK(64447) : > : > If it says 255 it's the old ROM, no Unidisk. : > If it says 0 then it's the Unidisk ROM. : > Then 3 is the memory expansion model, will : > allow Unidisk, and 4 is memory expansion : > model, Unidisk, and bugs fixed. The IIc+ : > is the only one that returns a 5. : : My model returns 255, so it is the original ROM. : Is there any advantage to updating the ROM? Does : it involve anything more than swapping a chip? : I tend to think not, because if it were it would : probably be talked about more. Heck, I'll talk about it. There is the need for the increased ROM from the normal 16K ROM to the newer 32K ROM. Now when you double the ROM size, there must be an address line added. This is already available on the motherboard, but in the form of opening one trace and closing another. If you look at your IIc motherboard near the front and to the left of the larger chips, there is a jumper pad called "W1". This pad must be cut in order for the increase to 32K ROM. Also there is another pad similar to this, more to the right near the ram chips and slightly back from the W1, which is called "W2". This one must be soldered. Now we have enabled the extra address line that allows the 32K ROM chip to be used. Also, I believe that this allows the ability to read the eprom version of the chip rather than the PROM one. Sometimes, as in the case of the II and II+, the ROMs are not pinned the same as an eprom of the same value. This could be the case here as well. Anyway, this is the basic procedure for adding the UniDisk ROM to the IIc original version. If you need this ROM, I can send you one, and also I can send you the expansion ram version, although the ram cards are very rare for the IIc. Bill @ GarberStreet Enterprizez };-) Web Site - http://garberstreet.netfirms.com Email - willy46pa @ comcast DOT net Change DOT to a dot to contact me --- This email ain't infected, dude! Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.634 / Virus Database: 406 - Release Date: 3/18/04