Joan,
I have been able to use the SDExplorer with the PNY reader. I have also been able to get some use out of the multi card "generic" reader. The PNY seems more reliable.
Fran,
The trick does seem to be to ALWAYS format the SD card in the keyboard and save one file to it, then use the SDExplorer to edit and save the files on the card. When I initilaized the card in the SDExplorer and did a restore, the 2600 could not read the card. It acted just fine in the SDExplorer. Whn I formatted the card in the keyboard and did the restore with the SDexplorer, the keyboard had no trouble reading the card.
I have found the tool extremely useful, just not without "quirks", perhaps all self induced. So far I have been able to find "work arounds"
Bill