Amiga 500 trapdoor ram not working

[username1]

Hi everyone. Pulled out my 500 today to find my trapdoor ram is no longer recognized by the system. I have a rev 6a motherboard that has been modified to use trapdoor ram as chip ram. I have a 512k trapdoor card installed. J2/J7A are set up correctly and I have an ECS Agnus. I also have an HC533 installed which provides a 33mhz accelerator and 8mb fast ram alongside an IDE connection.

However, my system only shows 512k of chip ram, both in workbench and Sysinfo. I have made sure the card is enabled by moving the switch in both positions and I can't find any damage on the card: I can't find any continuity breaks and the battery has 3.6V. I also confirmed all continuity on the connector from the mainboard to the ram card. Sysinfo and workbench detect 512k Chip ram and 8MB fast ram. Sysinfo detects that a clock is present and my Amiga will hold time correctly, so that portion of the card works, but I am not seeing the 1Mb of chip ram that I expect.

I'll attach photos of Sysinfo and my Ram board in the hopes that someone else can spot the problem keeping my system from fully working. All Sysinfo photos were taken with the board installed and enabled.

 

[dmac]

This is a very interesting issue.

Note that re: J2/J7A... you only need to set J2 IIRC, as the switch in your trapdoor card likely cuts the same line J7A does.

For lack of better ideas, I'd ensure J2 is still set properly (continuity between the two pins that are supposed to be connected, and none to the other pin).

My only guess right now is that the Amiga sees the RAM, but upon testing decides it's not in good shape and opts to not add it to the pool.

Does any of the expansion RAM chips get hot? What does amigatestkit think about the ram?