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I present to you an EVT TNT Power Macintosh 7500 Prototype Board and More

jajan547

Well-known member
To begin I would like to first say I'm ecstatic to have this board and I plan on putting it in a 7500 case (sadly I have no case or ROMs for this board) and hopefully tracking down or with the help of someone here creating a new ROM SIMM. This is pretty unique in that it is an EVT which don't typically show up in the wild. This board has a date of 1994 TNT BOARD REVISION 820-0564-05, EVT-3. This board also came with an external video connector board I assume this to also be a prototype as it's markings say "AV HOISDEN" with a part number of 820-0609-01 dated 1994. I have added photos below and will elaborate further....

Screen Shot 2022-09-15 at 9.38.35 PM.pngScreen Shot 2022-09-15 at 9.38.51 PM.png
The board as we can see has a somewhat odd layout compared to final units, things clear to me such as apparent reset and interrupt switches, missing or different connectors, no on board ROMs.




Screen Shot 2022-09-15 at 9.39.18 PM.pngScreen Shot 2022-09-15 at 9.39.30 PM.png
I know you see the weird chip with wires more on that further down.... As we can see no on board ROMs are present
tempImageIscYgI.jpgtempImage3AkRqu.jpg
Apparent Reset and Interrupt Switches

tempImage3x1dJV.jpgtempImagejaybSF.jpg

tempImageeFqbaI.jpgtempImagekQ0XeB.jpg
tempImageFdqOk5.jpg
Serial Number is *FC506VJNEVT*

tempImagemtWMD0.jpg
EGRET appears to be a 341S0060

tempImageY8wzLJ.jpg

tempImageJeFTGB.jpgtempImageGztgYO.jpg
Better view of more chips on Board

tempImageVye2cf.jpgtempImageE767Z3.jpg
Now for the chip you all are probably very interested in it appears Apple had issues with this chip and decided to try hijacking it or piggybacking a chip.
As can be seen many bodge wires done by an Apple Engineer are attached to a 44 pin PLCC socket which connect to an AMD MACH210A-10JC. I assume there's a great interest on reading this chip and what's on it I currently don't think I have a programmer (all I have is a TL866ii Plus) that can read this chips contents (correct me if I am wrong). I would love to extract whatever information is this little chip but I want to go about it the right way, if you're interested in helping PM me :).

Now onto the little Video Board "AV Hoisden" (820-0609-01)
tempImage9enpJ5.jpgtempImage1WBMwA.jpgScreen Shot 2022-09-15 at 9.39.51 PM.png

Things I still need are a donor 7500, a ROM SIMM, a Recap, and to of course move the ticking time bomb that is a Maxell Battery. I hope you guys enjoyed this. If you have any questions, ideas, feedback, or anything please feel free to PM me or comment below. Im interested in learning more about this.
 

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slomacuser

Well-known member
Great :) looks like a fun project for you. I can ship you RAM, video RAM, ROM and some PCI cards to try ;)
 

joshc

Well-known member
I think I'm right in saying this, as I vaguely recall a fairly lengthy thread about it... Be careful about how you wire up a PSU for that board, as 7x00 series boards seemed to have different pinouts and there was a lot of confusion as to which pinouts belong to which 7x00 board. @mg.man Does that ring a bell?
 

mg.man

Well-known member
I vaguely recall a fairly lengthy thread about it...
I believe you're referring to this one --
 

macuserman

Well-known member
Haha that’s my thread! I think I probably have enough spare parts for these darn machines to make a whole new one including the chassis/case. I was on quite a quest there for awhile. Where the blazes are you located @jajan547 ?
 

Phipli

Well-known member
I have mixed ROM and CACHE on 6100 without damage so you can try ...
How do you mean? I'm not certain but think you are talking about how you can switch the ROM and cache on Nubus PPCs? Or switching ROMs between similar macs?

The ROM and cache slots are different sizes on a 7500 os you can't mix them up. Like I mentioned in the thread, the 7500 uses an identical ROM to the 7200, 8500 and 9500 so a simm version of those could be used no problem.
 

slomacuser

Well-known member
How do you mean? I'm not certain but think you are talking about how you can switch the ROM and cache on Nubus PPCs? Or switching ROMs between similar macs?

The ROM and cache slots are different sizes on a 7500 os you can't mix them up. Like I mentioned in the thread, the 7500 uses an identical ROM to the 7200, 8500 and 9500 so a simm version of those could be used no problem.
Pm6100board.png
6100.jpg
 

jajan547

Well-known member
Haha that’s my thread! I think I probably have enough spare parts for these darn machines to make a whole new one including the chassis/case. I was on quite a quest there for awhile. Where the blazes are you located @jajan547 ?
I’m located in the USA, North Carolina specifically. Still there is the problem of finding the simm as you can imagine I don’t want to solder ROMS to an EVT board, can I yes but I want to track down one.
 

al kossow

Active member
To begin I would like to first say I'm ecstatic to have this board and I plan on putting it in a 7500 case (sadly I have no case or ROMs for this board) and hopefully tracking down or with the help of someone here creating a new ROM SIMM. This is pretty unique in that it is an EVT which don't typically show up in the wild. This board has a date of 1994 TNT BOARD REVISION 820-0564-05, EVT-3. This board also came with an external video connector board I assume this to also be a prototype as it's markings say "AV HOISDEN" with a part number of 820-0609-01 dated 1994. I have added photos below and will elaborate further....

View attachment 46628View attachment 46629
The board as we can see has a somewhat odd layout compared to final units, things clear to me such as apparent reset and interrupt switches, missing or different connectors, no on board ROMs.




View attachment 46630View attachment 46631
I know you see the weird chip with wires more on that further down.... As we can see no on board ROMs are present
View attachment 46633View attachment 46634
Apparent Reset and Interrupt Switches

View attachment 46635View attachment 46648

View attachment 46636View attachment 46637
View attachment 46638
Serial Number is *FC506VJNEVT*

View attachment 46639
EGRET appears to be a 341S0060

View attachment 46640

View attachment 46641View attachment 46642
Better view of more chips on Board

View attachment 46643View attachment 46644
Now for the chip you all are probably very interested in it appears Apple had issues with this chip and decided to try hijacking it or piggybacking a chip.
As can be seen many bodge wires done by an Apple Engineer are attached to a 44 pin PLCC socket which connect to an AMD MACH210A-10JC. I assume there's a great interest on reading this chip and what's on it I currently don't think I have a programmer (all I have is a TL866ii Plus) that can read this chips contents (correct me if I am wrong). I would love to extract whatever information is this little chip but I want to go about it the right way, if you're interested in helping PM me :).

Now onto the little Video Board "AV Hoisden" (820-0609-01)
View attachment 46645View attachment 46646View attachment 46647

Things I still need are a donor 7500, a ROM SIMM, a Recap, and to of course move the ticking time bomb that is a Maxell Battery. I hope you guys enjoyed this. If you have any questions, ideas, feedback, or anything please feel free to PM me or comment below. Im interested in learning more about this.
I would love to extract whatever information is this little chip.
It is a workaround for a bug in the Hammerhead memory controller.
 

Bolle

Well-known member
Yes, with an appropriate programmer and if the chip doesn’t have the security bit set. Not sure if they’d secure it because it supposedly never should have never made it to the public. So worth a try to read it out.
 

jajan547

Well-known member
Yes, with an appropriate programmer and if the chip doesn’t have the security bit set. Not sure if they’d secure it because it supposedly never should have never made it to the public. So worth a try to read it out.
I’d love to know what’s on it I’m sure it’s some pretty interesting if not valuable information I wonder if anyone has a programmer nearish to me.
 
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