Warning: GRiD cards ad for 48GX

[Richard Reed]

On TAS, seller 'coburlin' is showing two 1MB cards labelled GRiD as "FOR HP 48GX". If I'm not mistaken, it was these Epson-built cards that did not have the HP changes for lower voltage levels, different from GRiD, at which 48GX is allowed to operate. It has been reported from several reliable sources that when calculator battery voltage in 48GX gets to a lower, still operable value, the GRiD cards clamp address and data inputs low while the calculator is still driving them, effectively shorting the calculator power supply.

The result has been reported variously as sudden low battery indication on new-ish batteries, loss of user memory, permanent calculator power supply damage, and "never saw any problem".

coburlin's prices are always too high for me anyway (no auction).

Please correct me if something about GRiD cards later changed to eliminate this problem.

Richard

Edited: 3 Oct 2009, 2:54 p.m.

[Norris]

(Much) more info about the potential hazards of Epson cards in the HP48
here

Edited: 3 Oct 2009, 9:11 p.m.

[Bart (UK)]

Corrected link.

An extra http// had slipped in :)

[Richard Reed]

I also found this response to a 'GRid OK' post from August 1998, specifically about 1MB GRiD card problems in 48GX. I think there were a number of good alternative makes after this, but I sympathise with the poster's 'HP-only' opinion at the time (response poster name is Dan Kirkland).

1MB GRiD in 48GX

Edited: 4 Oct 2009, 8:43 p.m.