68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.
Does anyone have a 7500 ROM SIMM and if not are there modern day programable ones?
Posted by: mgmac on 2022-09-21 11:25:05 Isn’t that just a cache? opss sorry I have read 8500, not 7500, my mistake you have 7500, not 8500, sorry
Posted by: mgmac on 2022-09-21 11:27:06 if you tell me the exact code, It is possibile I have it for your PMac 7500
Posted by: jajan547 on 2022-09-21 11:28:57 if you tell me the exact code, It is possibile I have it for your PMac 7500 I don’t know what the simm number was all I know are the four ROMs commonly found on the boards.
Posted by: mgmac on 2022-09-21 11:39:49 found anything in the 7500 motherboard online pictures? it's weird because it's a very common Mac model If you find the code, I can check if I have it
Posted by: jajan547 on 2022-09-21 11:43:05 found anything in the 7500 motherboard online pictures? it's weird because it's a very common Mac model If you find the code, I can check if I have it Well most had on board mine is an EVT without on board ROM so what I want to do is find a simm from a 7300, 7500,7600, 8500, or 9500 so I can boot it. I hate to solder ROMs to an EVT board that had them simm based
Posted by: mgmac on 2022-09-21 11:46:19 yes, I understand, try to see if it finds the correct simm code
Posted by: jajan547 on 2022-09-21 11:48:26 yes, I understand, try to see if it finds the correct simm code I’ll try ive been looking through what documentation I’ve found in my Vol 5 service guide (in the wiki section here) it talks about the ROM simm but not the number annoyingly
Posted by: Performa450 on 2022-09-22 01:07:44 I’ll try ive been looking through what documentation I’ve found in my Vol 5 service guide (in the wiki section here) it talks about the ROM simm but not the number annoyingly Might be worth looking in service manual pics if they haven’t. They often picture prototype boards, but may well be too low res to get the part number.
Posted by: jajan547 on 2022-09-22 05:01:45 Might be worth looking in service manual pics if they haven’t. They often picture prototype boards, but may well be too low res to get the part number. I found some old parts guides with simms but most appear to be cache and older before the 7100
Posted by: jajan547 on 2022-09-22 23:29:39 Hmm was sent *this* link by @Jockelill and it looks interesting, suppose this would work? provided I find a ROM SIMM from another PPC machine.
Posted by: jajan547 on 2022-09-23 19:53:55 All of these SIMMs will boot my board if anyone has one PM me Power Mac 7200/75/90/120/120PC Power Mac 7215/90 Power Mac 7500 Power Mac 7600/120/132 Power Mac 8200/100/200 Power Mac 8500/120/132/150/180 Power Mac 8515/120 Power Mac 9500/120/132/150/180MP/200 Power Mac 9515/132
Posted by: domii on 2022-09-24 06:08:30 I looked on ebay, there are a bunch of 7200 logic board listings under $60 that look like they have the rom simm on them. Maybe cross reference with a layout/picture to make sure its not the cache card. https://www.ebay.com/itm/161262787915 https://www.ebay.com/itm/161396496508 https://www.ebay.com/itm/234669026146 But that would be your best bet.
Posted by: Phipli on 2022-09-24 06:15:40 Maybe cross reference with a layout/picture to make sure its not the cache card. Sadly they're all cache cards. Please forgive the messy mark-up, I'm on my phone, but you can see the silkscreen in this markup. SIMM ROMs are really unusual in this era of machine.
Posted by: jajan547 on 2022-09-24 12:54:50 Sadly they're all cache cards. Please forgive the messy mark-up, I'm on my phone, but you can see the silkscreen in this markup. SIMM ROMs are really unusual in this era of machine. View attachment 46830 Yeah I’m beginning to think maybe take a 6100 rom simm and flash new 7500 ROMs to it/replace the chips.
Posted by: trag on 2023-03-10 13:24:31 @jajan547 Sorry I didn't see this thread sooner. I've been away from forums for a while. Really TL😀R summary: Look for a module with four chips on board. The chips are labeled 341S0169, 341S0170, 341S0171, 341S0172. That will work, even if it is a PowerComputing Corp. (PCC) module. If you can't find one let me know and I can probably hook you up. But note that I've been busy enough to not read the forum for most of a year and my response times are likely to be poor. I can also manufacture any ROM you want, but then you're talking really long lead times: https://68kmla.org/bb/index.php?threads/pex-rom-project.23568/ ======================================= The Power Computing Corp. ROM modules can definitely be used provided that pin 116 is tied High (5V) on the module. Pin 116 of the socket runs to the CE_ pins of the on-board ROMs, so tying it high on the module pulls CE_ of the on-board ROM chips high and disables them. http://sphinxgroup.org/Apple_pinouts/Firmware_Module_Pinout.txt Oh, but that doesn't matter for you because you have no on-board ROM chips. So, you can just install a PCC ROM module and it will work. Plus, IIRC PCC ties pin 116 high. They just copied the Apple design. Except... PCC also sold a NuBus PowerMac clone and the ROM for that will not work. You need any of the PCC ROMs that were not made for the Power 80, Power 100 or Power 120. More on identifying ROMs below. TL😀R stuff... (note, X500 refers to the 7500, 8500, 9500; does not refer to the 5500, 6500 or any other machines) The following Apple machines used the same firmware (ROM) module circuit board/pinout: NuBus PowerMac, PM7200, X500, X600, ANS, Beige G3, PEx. Of course the code installed on the ROM chips was different for each family of machines, but the hardware module remained the same. The firmware used on the PM7500 is $77D.28F2. There was actually an earlier version, $77D.28F1 (IIRC) and that might be most appropriate for you, as that was the earliest I've found. Note that $77D.34F2 (X600 original) and $77D.34F5 (X600 "Enhanced", AKA Kansas) will also work. So you have these choices found on these chips: $77D.28F1 341S0106, 341S0107, 341S0108, 341S0109 $77D.28F2 341S0169 - 341S0172 $77D.34F2 341S0280 - 341S0283 $77D.34F5 341S0380 - 341S0383 The first column is the ROM revision number reported in Apple System Profiler. The second column is the four Apple Part Numbers found on the four ROM chips used on the ROM modules, or soldered directly to the logic board. These part numbers are on the chips, not on the circuit board. All of the PM7200 also used either the $77D.28F1, or the $77D.28F2. $77D.28F2 is by far more common. I've only seen a very few examples of the $77D.28F1. Every (non-NuBus) Power Computing module I've ever seen has the $77D.28F2 on board. There were also various modules out there with EEPROM or Flash chips on board. Apple had some kind of reprogrammable module. It looks like @al kossow knows a lot more about it than I do. I've just seen a few examples over the years. I think the ROM module in the DigiBarn PEx machine looks like the modules that Al posted an image of.
Posted by: jajan547 on 2023-03-11 21:11:58 This is amazing to hear! If you can make me a ROM that would be awesome I have no rush on it either but please do let me know. I'd probably go for the earliest version you've found if you can.
< 4