Sharp EL-9650 Equation Editor - This one fom 2001

[jebem]

This SHARP EL-9650 programmable scientific graphics touch screen calculator, together with the almost identical EL-9600, were the first ever handheld calculators in the market with a touch screen.

The EL-9600 was released in 1997 and this EL-9650 was released in 2000.
This is a good reason to grab one of these to your collection IMHO.
I got this one new in the box from an Iberia seller. It was barely used, the calculator doesn't even has those typical lateral "scratches" from the sliding cover operation. The user guide was never used and the machine still had the original batteries.

Much later, in 2003, CASIO has released similar touch screen feature with their Classpad series. So CASIO was the second to market that feature AKAIK.

The black LCD is good despite requiring good light conditions to be easily readable.
Non optimal light conditions will blurry the display a little but the contrast adjustment will help a little here.
I believe these constraints are the result of the chosen passive non-back light LCD technology combined with the extra touch screen film layer that requires additional light conditions for a more easy reading.

Aesthetically the calculator is not bad but is lacks the refinement of later SHARP machines.
That said, the key labels are very easy to read under any light conditions, contrary to what other well respected calculator brands have done years after.




Main hardware/firmware features obtained from the official SHARP site and user guides:

Black LCD Touch Screen;
Text mode: 22 Digits x 8 Rows. 5x7 dot matrix chars;
Graphics mode: 132 x 64 pixels;
Touch Screen matrix: 22 x 8.

Program mode: Up to 99 programs.
RAM Memory size: 32KByte.

User register memories: 27
Functions: 801 (The similar EL-9600 model has 797 features)

Communications: Serial Unit to Unit (CE-450L kit) or Unit to PC (CE-LK1P kit).

Power Supply:
Battery 4 x AAA (Power consumption: 0.13W at 6VDC)
Memory backup: CR-2032

Precision:
In normal mode: 10 digits mantissa 2 digits exponent;
In complex mode: 10 digits mantissa;
Using split Screen: 7 digits mantissa.


Forensics test result: 8.9999999771708




I like when a calculator is able to give a straight positive answer to sqrt(-2).
Also it was swift to find the correct answer to the integral of int(0,pi, sin(x)dx).




Graphical representation of combined functions.




This calculator manufacturing date was around 2001.
The included original Japanese batteries have a date code of 01 09 (2001, September).
Also the IC4 and IC5 SHARP chips shows date codes for the year 2001, week 45 and 44.




Dismantling.

When the battery cover is removed, the main battery power supply is switched off automatically thanks to a pressure switch visible in the picture at the left side of the memory backup battery cell.
I don't recall this feature in any other calculator.




To remove the back cover we need to undo six screws.
The main PCB is covered with a screening foil that requires an additional screw to be undone in order to remove it.




PCB Integrated Circuits:
IC1: Unmarked (LCD/Touchscreen driver?)
IC2: Unmarked (Processor?)
IC3: EPSON SRM2B256SLTMX1 256KBit (32KByte) Static RAM
IC4: SHARP LH5S4ATA 4Mbit (512KByte) Mask ROM (date code 0145: 2001 week 45)
IC5: SHARP LZ9GA34 LCD/Touchscreen controller (date code 0140: 2001 week 40)

Despite what looks like a pogo connector visible above the SW2 switch and accessible from the exterior, this model doesn't support firmware updates because it uses a LH5S4ATA MROM memory. SHARP has chosen the cheapest solution possible here just enough to fulfill the project specifications.