Macintosh II with ROM-SIMM

Kay K.M.Mods

Kay K.M.Mods

Active Tinkerer
Sep 23, 2021
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www.kerosmm.com
It's been about 2 weeks since I got the Macintosh II Rev.B, but I've replaced the 8 RAM sockets on it and have been recapped.
This time I couldn't stand it and tried to see if the ROM-SIMM pattern hidden under this ROM socket worked.

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The ROM used is IIxIIcxSE30_512k.bin. I tried other ROMs but it didn't work. The original ROM is 512KB, and since the image was written twice, it was necessary to erase the unnecessary latter half. As a result, I made it 256KB.
This is divided into 4 parts and written. The program used SRecord. The SIMM used is from GG Labs and can be flashed using the TL866II.
This made my Mac II partially Rev.C.
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The ROM-SIMM project that Zane is currently working on is almost over, and these are also compatible with Mac II. So now you don't have to look for expensive and rare IIx ROMs. (* but SWIM is difficult to obtain... II has a PLCC28 socket IWM, I have only PLCC44 SWIM from IIfx.)
I'll renting a ROM-SIMM programmer from tester JDW , so I'll be reporting this soon. * My programmer is incomplete.
https://www.tindie.com/.../gw4402a-8mb-rom-simm-for-mac.../

 

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trag

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Oct 25, 2021
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Nice work. About the SWIM, Utsource quoted me $110 each with a minimum of 100 last week. I don't know who is going to spend $11,000 on SWIM chips...

It does imply that there are far more than 100 available, though.
 
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max1zzz

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trag said:
Nice work. About the SWIM, Utsource quoted me $110 each with a minimum of 100 last week. I don't know who is going to spend $11,000 on SWIM chips...

It does imply that there are far more than 100 available, though.
Click to expand...
I'm almost more impressed you actually got a quote back from UTSource! I don't think a single one of my inquiry's has actually resulted in me getting a quote.....
 
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trag

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max1zzz said:
I'm almost more impressed you actually got a quote back from UTSource! I don't think a single one of my inquiry's has actually resulted in me getting a quote.....
Click to expand...

I had a ~$900 order ready to go with them based off of one quote and otherwise their web page. Then the emails from them started rolling in. Oh, sorry, we don' t actually have any of the RTC or ADB chips we listed as 30,000+ in stock. The Flash you wanted is 5 times the price that's on our website. Several other issues. Higher prices. No stock.

I ended up cancelling the order as a bad Bait and Switch job. Would have been nice to get the SE/30 Sound chips they actually quoted at $1.75 each, but I really, really didn't need 100 of them. Would have bought them with the other stuff though, figuring the community would use them eventually, but they just irritated me too much.

Maybe more patience and a phone call where one asks them to confirm all the prices. They have a toll free number.
 
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max1zzz

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Yeah I have had that before.... I'm still annoyed that the LC475 memory controllers they listed as in stock weren't!

Though saying that most of what I have tried to order that they have listed as in stock has actually been in stock at the price they listed.
They are a useful source of obscure parts, just a little frustrating to use at times....
 
Kai Robinson

Kai Robinson

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max1zzz said:
Yeah I have had that before.... I'm still annoyed that the LC475 memory controllers they listed as in stock weren't!

Though saying that most of what I have tried to order that they have listed as in stock has actually been in stock at the price they listed.
They are a useful source of obscure parts, just a little frustrating to use at times....
Click to expand...
I think i might have 4 of those...lemme check tomorrow :) the djMEMCjr, right?
 
lilliputian

lilliputian

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Mar 6, 2022
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My Mac II has a SWIM chip installed, and updated ROMs (the "FDHD" upgrade). I have a TL866II (though I've yet to actually use it for anything). Assuming I got the correct EPROM adapter for the SWIM PLCC, would that be something that could be dumped?
 
T

trag

Tinkerer
Oct 25, 2021
280
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lilliputian said:
My Mac II has a SWIM chip installed, and updated ROMs (the "FDHD" upgrade). I have a TL866II (though I've yet to actually use it for anything). Assuming I got the correct EPROM adapter for the SWIM PLCC, would that be something that could be dumped?
Click to expand...

Unfortunately not. The SWIM chip is an actual logic chip, not a memory or storage chip. It is not the kind of thing that can be copied and programmed into another blank chip.

That said, if someone does a lot of hard work and figures out the logic going on inside the SWIM, it might be possible to program a CPLD to imitate it, but I wouldn't hold my breath for that. It would be a fairly big project.
 
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