You surmise correctly - I've been requesting various bits of information to check into my options for the 6 1MB cards that I recently got.

Option 1 - buy additional chips and upgrade the cards to 3MB... the cards are identical (resistors, chips, everything).

Option 2 - canibalize the existing card's chips - the yield is 2 3MB cards and 4 empties

Option 3 - if, as I suspect, there are minor differences between the 3 and 7 MB cards, get the different chips and make the additional modifications (if any)

hopefully, I will be able to put together 7MB cards - I really want to upgrade my Mac Portable