HP-75 RAM expansion?

[Martin Hepperle]

Dear HP-75 experts,

some weeks ago I read somewhere among my CD/DVD files an old publication about a home made RAM upgrade for the HP-75 using two RAM chips. These were to be soldered piggyback on existing RAM chips and the corresponding Chip Select lines routed to the PCB.
The article also explained that one has to mill out part of the case down to the metal cover plate to provide enough space.

Now I cannot remember where I read this. I believe that this was in some conference proceedings, but I cannot find them anymore.

Does anyone remember?

Thank you,
Martin