HP 48 ram card from Ebay: why would self-test be required?

[trojdor]

I've bought the same cards from the same vendor, and first one was a bad one...
But the guy was good/fast about replacing it and the second one was perfect.
I've seen no difference between these and several actual HP cards in the GX's I've got.

(But like mfleming said, don't try them in an SX....I had to pull the foot and use the paperclip reset to get mine to come back to life, lol.)

mike