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

[jajan547]

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]

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]

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]

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.

 

[jajan547]

If someone’s willing to work with me on this I can cover cost of materials.

 

[macuserman]

I probably have an entire board as a spare including the rom somewhere if your not in a rush.

 

[jajan547]

I probably have an entire board as a spare including the rom somewhere if your not in a rush.

Not in a huge rush but really need the simm if you have it.

 

[Phipli]

Wait, are you saying there aren't any chips soldered *here* on the underside of the board @jajan547?

 

[jajan547]

Yeah mine are not there it’s an EVT board I’ll post photos this afternoon.

 

[Phipli]

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

 

[jajan547]

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

I know but I need a simm that’s my issue, I cannot locate one.

 

[slomacuser]

Would one of of these roms fit? Some are cache but mostly roms

 

[jajan547]

Would one of of these roms fit? Some are cache but mostly roms
View attachment 46607View attachment 46608View attachment 46609

I don’t see those ROMs matching the ones above, now I’m not very familiar with too much PowerPC stuff and compatibility but the ROM simms themselves appear correct. Would these work?

 

[Phipli]

Would one of of these roms fit? Some are cache but mostly roms
View attachment 46607View attachment 46608View attachment 46609

The ones that match have 50,50,60 pins, but be careful - are these from Beige G3s? Some of them absolutely are. A G3 ROM wouldn't boot a 7500, and might not be electrically compatible.

 

[Phipli]

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.

 

[Phipli]

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]

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]

Would one of of these roms fit? Some are cache but mostly roms
View attachment 46607View attachment 46608View attachment 46609

@slomacuser are there chips on the other side of this one?

If there are it might be what is needed, although may need reprogramming.

Edit : no, sadly it is single write ROMs. It isn't reprogrammable.

 

[Phipli]

What do you want to say here?

You have too many parts, it makes me sad because each part represents a dead machine.

 

[Phipli]

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.