68kMLA Classic Interface
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| Click here to select a new forum. | | Macintosh II ROM type | Posted by: karrots on 2020-12-08 22:11:56
Does anyone know the equivalent EPROM chip for the Macintosh II?
I assume its either 4x 27C512 or 4x 27X128.
| Posted by: trag on 2020-12-08 22:55:21
The Mac II uses a 256KB (kilobyte) ROM distributed across four equal sized chips, so each chip has a capacity of 64KB.
Chips are specified in their bit or Kilobit or megabit capacity. So the 27C512 has a capacity of 512/8 = 64KB. That would be the one you need.
Note that almost any storage chip in the correct package should work, e.g. 28C or 28F and 29C and 29F series. The only thing to watch out for in those other cases is that there may be a WE_ pin or a _Reset pin that must be tied to 5V, which is easy enough with some wire wrap.
| Posted by: karrots on 2020-12-11 17:46:31
Thanks
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