Questions about Applied Engineering Ram Keeper eprom revision 1.7 on ROM 03

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June 20, 2026 - 12:18pm
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Sid6.7
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Questions about Applied Engineering Ram Keeper eprom revision 1.7 on ROM 03

Hi everyone.

 

My RAM Keeper has arrived. I tested it on a ROM 01 machine and there don’t seem to be any major issues, except that I wasn’t able to get the RAM2GSII GW4201D from Garrett Workshop to work, while the official Apple 1MB expansion card worked fine.

My main goal, however, is to get it working on a ROM 03 system. For that purpose, I performed the modification on the 74F27N NOR gate as required.

Now I have a problem. If I leave the original 2764 with firmware 1.4 installed, when I power on the IIgs I get a “nice” (so to speak…) Invalid RK Configuration 0102 error.

I programmed a NEC D27128D with firmware 1.7: Name: RamKeeper_ROM_1.7.bin Size: 16384 bytes : 16 KiB SHA256: 9e932ad068e2e824002e7fb3bcb1b91624548de614306f7c88fcd7cbc01e85b0

However, with that EPROM the IIgs behaves at startup as if the RAM Keeper wasn’t installed at all. Do you have any advice regarding a specific model of 27128 EPROM that is known to work reliably, and possibly any tips on how to program it correctly using a GQ‑4X4 programmer?

Thanks in advance to anyone who can help.

 

 

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June 21, 2026 - 6:46am
robespierre
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???

Where did you read that the modification was required for the ROM 3?

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June 21, 2026 - 7:08am
CVT
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robespierre wrote:Where did
robespierre wrote:

Where did you read that the modification was required for the ROM 3?

 

Here: AE RamKeeper - ROM03 Mod.pdf

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June 21, 2026 - 7:14am
robespierre
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I saw that file too, and

I saw that file too, and despite the file is named "ROM03 Mod", the instructions seem to belie that. It tells you to swap the chip if you have a ROM1.

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June 21, 2026 - 8:00am
CVT
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robespierre wrote:I saw that
robespierre wrote:

I saw that file too, and despite the file is named "ROM03 Mod", the instructions seem to belie that. It tells you to swap the chip if you have a ROM1.

 

Yes, and from one of the other threads I can see that he has the revised RamKeeper, which is ROM3 ready and no modification is required.

 

To the OP: spreading the same discussion over 5 threads doesn't help the situation. It just makes it very difficult to follow.

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June 27, 2026 - 2:42am
Sid6.7
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Questions about Applied Engineering Ram Keeper eprom revision 1.
Hi everyone. I had found some official Applied Engineering documentation that described the issue as if the TTL in question needed to be modified when the IIgs where the RamKeeper is installed is a ROM 03. Anyway, I restored the TTL to its original state, updated the firmware to release 1.7, and now it works on my ROM 03. However, I still have some doubts. I managed to create a 6.5 MB ROM Disk. After creating it, I formatted it and copied the GS/OS 6.0.4 files onto it. Booting from the ROM Disk works. It works, in fact, despite the information I’ve read about a bug in the IIgs ROM 03 that supposedly prevents booting from a RAM Disk/ROM Disk if a SmartPort controller is present in the system. Despite this, booting from the ROM Disk works. Now, the Garrett Workshop Ram2GS GW4201D, set to 8 MB, is not detected by GS/OS. Instead, I only see 1152 KB of RAM, which is still enough to boot GS/OS without issues. My question is: if I had the SlotMover installed, would I be able to have a 6.5 MB ROM Disk and simultaneously 4 or 8 MB of RAM?
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