Fun with SE

[frontein1]

Bought @derFunkenstein's CatMac SE. Thank you @derFunkenstein, this is a great little machine. And of course the first thing I have to do is pull the ROM chips

Thanks to @WillJac over at CayMac for pointing me towards OneROM. What an incredible concept! Totally seamless to take the 28-pin OneROM and program it to match the pinout of the original TC531000 mask chips. @WillJac is traveling for a while, but make sure to stop by his Ko-Fi store!

Now off to Kero's Mac Mods to pickup the SWIM adapter board to complete the transition from SE to SE FDHD.

 

[pom]

One ROM - The Most Flexible Retro ROM Replacement

The most flexible retro ROM replacement - open source hardware and software.

onerom.org

 

[frontein1]

For those interested, here are the patches I made to the SE FDHD ROM to disable the slow memory test and the ROM checksum fail:

offset 0x0084 change 6704 -> 6004
offset 0x0011C change 6704 -> 6004
offset 0x26EA change 3C3C FFFF -> 4E71 4E71

 

[pom]

can you tell more about oneROM. Looking at the website, the Macintosh SE doesn’t seem to be listed among the supported machines.

 

[frontein1]

can you tell more about oneROM. Looking at the website, the Macintosh SE doesn’t seem to be listed among the supported machines.

Yes I bet the site just needs this reference so the SE ROMs can explicitly be listed. However the mask ROMs are really just the Toshiba TC531000 chips. These were pretty common back in the day. Below is a screenshot I took while burning the HI ROM file. The ROM Type TC531000 is already listed as supported when burning the Fire 28.

 

[pom]

Thanks for the details. Very interesting. What other hacks could be achievable?
Do you reckon you could embed a bootable system ?

 

[derFunkenstein]

Bought @derFunkenstein's CatMac SE. Thank you @derFunkenstein, this is a great little machine. And of course the first thing I have to do is pull the ROM chips

Thanks to @WillJac over at CayMac for pointing me towards OneROM. What an incredible concept! Totally seamless to take the 28-pin OneROM and program it to match the pinout of the original TC531000 mask chips. @WillJac is traveling for a while, but make sure to stop by his Ko-Fi store!

Now off to Kero's Mac Mods to pickup the SWIM adapter board to complete the transition from SE to SE FDHD.

View attachment 98149View attachment 98148

Really happy to see that it’s working out well for you! And way to give it new life with some new ROMs and floppy controller

 

[frontein1]

What other hacks could be achievable?
Do you reckon you could embed a bootable system ?

Unfortunately we are really restricted by the number of address lines exposed to the ROM sockets. We'd need a Rominator type board and bodge wires clipped or soldered to the 68000. Unfortunately this approach would probably make it pretty impossible to use an accelerator card as well.

I think something like this was sort of done in the reverse order at one time to allow EPROMs to be plugged into the 28-pin sockets. But I don't think that would fix the address limitation.

The checksum and memory test patches are certainly a help. However I haven't really spent a lot of time inside the SE ROM, and maybe I will do that now.

And way to give it new life with some new ROMs and floppy controller

Yes working just great. I really like having the CatMac form factor for this and the MacPlus. With clean boards and no batteries to worry about, it is almost like these two machines are now future proof.