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Does anyone have a 7500 ROM SIMM and if not are there modern day programable ones?

jajan547

Well-known member
I ask because I have a board with no on board ROMs it needs a ROM SIMM (and yes I have looked and know where they should be), the ROM chip pads were left blank. As such my board will not boot. So I ask does anyone have one and if not are there modern day programmable ones similar to the GG Labs iisi, SE30, and IIFX ROM SIMM? If no to either of these questions would somebody be willing to work with me to create one?
 

Siliconinsider

Well-known member
Getting back to you since you reached out from eBay, it is indeed fairly unusual to have a board without ROM, maybe you have a very early one? Your best chance would be to find a battery bombed motherboard and transfer the ROM from it. I'm not sure there would be a lot of incentives to create a new ROM SIMM because there's no real need for one, unless, like the Rominator, you could boot from one maybe?
 

jajan547

Well-known member
Getting back to you since you reached out from eBay, it is indeed fairly unusual to have a board without ROM, maybe you have a very early one? Your best chance would be to find a battery bombed motherboard and transfer the ROM from it. I'm not sure there would be a lot of incentives to create a new ROM SIMM because there's no real need for one, unless, like the Rominator, you could boot from one maybe?
It’s indeed early board which I’ll be showing tomorrow, I’d just like to use a simm
 

Siliconinsider

Well-known member
Schematics would not be very complicated but it would be a lot of work to do the PCB layout, using flash chips of this density require 3.3v, so you'd also need 5V to 3.3V level shifters on the data and address bus.
 

Phipli

Well-known member
By the way, the ROM from other machines will work in it too. The 7200/8500/9500 ROMs are identical.
 

Phipli

Well-known member
I've thinned out the ROMs that look like they won't work. Where I've maked 6100, I mean 7100 and 8100 too. Please stop scrapping Nubus macs.

Ones I haven't marked don't mean they'll work, just I don't know that they won't.
 

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Phipli

Well-known member
Oh, and I put crosses on the caches because they're not ROMs, but you probably want one of the faster ones of those to speed the machine up.
 

slomacuser

Well-known member
I've thinned out the ROMs that look like they won't work. Where I've maked 6100, I mean 7100 and 8100 too. Please stop scrapping Nubus macs.

Ones I haven't marked don't mean they'll work, just I don't know that they won't.
Thanks for marking the roms :) can you identify the CACHE too? Which is for what machine?

Please stop scrapping Nubus macs.
What do you want to say here?
 

Phipli

Well-known member
I think the cache is as follows, but be warned you should match it to machines by how fast it is and the bus speed. Newer machines came with faster cache.
 

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