HP48GX Expansion

[Han]

The HP Brand ones will tend to be more expensive, followed by the data-collecting brands (e.g. TDS and SMI to name a few). After those come the PCB-only type of cards -- basically a PCB with all components exposed.

I own quite a number of memory cards and I actually find that the PCB-only cards are the most economical, and arguably more reliable. The major brand name cards (including HP) often come with better safeguards such as the retractable metal plate that supposedly guards the connector pins when the card is not inside the HP48GX. However, over time, these guards are the very reason for card issues -- they can sometimes cause shorts. I have had to even tape my HP 1MB card's metal guard to prevent it from coming down because it would often cause a short and the end result would be total destruction of data.

The other advantage of the PCB-only cards is that the PCB is generally very thick -- with components, they tend to be almost as thick as brand name cards. This means that they are very sturdy and will not bend over time. The brand name cards have much thinner PCBs because they are housed inside a metal casing. Over time, these cards can actually bend, causing contact issues. The glue inside them can also deteriorate, and then you have to fix them with epoxy or be left with a card whose casing could come apart.

PCB-only cards are also more likely to be battery powered. TDS and SMI have rechargeable batteries in some of their cards. I can only wonder what happens when those rechargeable batteries eventually die. HP cards and PCB-only cards have easy-to-replace batteries (fortunately).

The only drawback (for me) with the PCB-only cards is that they tend to not have an easy way to remove the cards. The brand name cards have a tab glued to the outside of their cases. While nice, even an HP brand card (stored in pretty much perfect conditions), have had their tabs "droop". One of my 128KB HP cards had its tab "slide" down to almost halfway. It is brand new, and was stored in a vertical position. I have now turned the box upside down in the hopes that it will eventually "slide" back to its original position so that I can then store the box and card laying flat.