I noticed that the HP48GX has a few extra ICs. Does anyone know what
are missing in the 48G? I see that the HP48GX has:

- card slot
- HC00
- HC174
- 473 (47k ohm res. below HC174)
- 104 (100k oh res. below HC174) <-- not sure about this one; is it
supposed to be a resistor or capacitor?
- some component near HC174; it looks like a Y shaped piece:

 |   |
  \ /
   |

Also, what does this last component do that makes it necessary in the
HP48GX and not the HP48G?

The parts are to address the additional (potential) memory of the
memory cards.  For a complet schematic of the HP48G/GX, see:

http://www.hpcalc.org/search.php?query=48+schematics

You can see how these components are connected to the card slots.

R,
TomC
ps:  I do have pics of a HP48G which I disassembled; let me know if you
would like pics.


Han wrote:
> I noticed that the HP48GX has a few extra ICs. Does anyone know what
> are missing in the 48G? I see that the HP48GX has:
>
> - card slot
> - HC00
> - HC174
> - 473 (47k ohm res. below HC174)
> - 104 (100k oh res. below HC174) <-- not sure about this one; is it
> supposed to be a resistor or capacitor?
> - some component near HC174; it looks like a Y shaped piece:
>
>  |   |
>   \ /
>    |
>
> Also, what does this last component do that makes it necessary in the
> HP48GX and not the HP48G?

"Han" <rs1n@hotmail.com> wrote in message 
news:1133276292.219418.136430@g47g2000cwa.googlegroups.com...
> Also, what does this last component do that makes it necessary in the
> HP48GX and not the HP48G?

If IRAM=32K then 48G
If IRAM=>128K then 48GX

Han wrote:
> I noticed that the HP48GX has a few extra ICs. Does anyone know what
> are missing in the 48G? I see that the HP48GX has:
>
> - card slot
> - HC00
> - HC174
> - 473 (47k ohm res. below HC174)
> - 104 (100k oh res. below HC174) <-- not sure about this one; is it
> supposed to be a resistor or capacitor?
> - some component near HC174; it looks like a Y shaped piece:
>
>  |   |
>   \ /
>    |
>
> Also, what does this last component do that makes it necessary in the
> HP48GX and not the HP48G?

Ahh yes, the 48G only has 32kB RAM vs 128kB RAM on the HP48GX. But back
to the Y-shaped component. I checked the schematics at hpcalc.org, but
it does not actually list the part. Also, it appears to look more like:

 _|___|_
|_______|
    |

The component is located just to the left of the blue capacitor-looking
component, to the left of the RAM chip (looking at the PCB with IR port
pointing up and battery pointing down).