CASIO FX-730P Personal Computer, Japan, year 1988

[jebem]

Recently I have acquired this nice CASIO FX-730P Personal Computer, made in Japan.

The manufacturing year should be near the end of 1988.
Why 1988?

Well, I have dismantled it, almost piece by piece, to clean it and of course to have a peek and see the inner details.

IMHO, these are properly well engineered machines, using good quality plastic and aluminum materials in the case, independent hard plastic keys, 15 steel screws to fix all together, and despite using modern SMD devices, all components are adequately soldered, so here we do not see cost saving pressure contacts for the LCD display nor plastic fused rivets to join components.

I'm impressed by the build quality and attention to details that Japanese manufacturers used to have in the late 80's, whatever the manufacturing plant they used (despite the "Made in Japan" notice in the back cover, probably the machine was already assembled in China).

Looking to the components, I see manufacturing dates like:

- Power Supply Capacitor, ELNA (what a great brand for caps!), 100uF, 16V, Year 87, week 35;
- HD61747B27 IC1 and HD61747B27B28 IC2 (CPU/KB/DISPLAY/RAM/ROM), year 88, week 43.
- MB64H193 (GATE ARRAY IO/MEMORY_CONTROLLER), year 87, week 48;
- HM6264ALFP-50 (RAM 8KBYTE CMOS STATIC MEMORY), year 87, week 44;
- TC4071BF (QUAD 2-INPUT OR GATE), year 88, week 04;

Images: Part 1

[jebem]

Images: Part2

[Nigel (UK)]

Great pictures - thank you! I've got one of these too and I find it a great machine. It's compact, comfortable to use, good to look at and with enough memory to hold several useful programs at a time. It is 25 years old but it feels like it will last for ever. I'm not taking mine to pieces, though!

Nigel (UK)

[Marcus von Cube]

If you can get hold of the cassette interface FA-3 my cassette io utilities might be a useful addition. http://www.mvcsys.de/doc/casioutil.html

[jebem]

(10-11-2014 11:20 PM)Marcus von Cube Wrote:  If you can get hold of the cassette interface FA-3 my cassette io utilities might be a useful addition. http://www.mvcsys.de/doc/casioutil.html

Thank You, Marcus.
That would be a nice addition to the collection.

I worked for WANG Computers Europe for so many years, and I started in 1980 by supporting the Wang 2200 initial series desktop computers with cassette storage at our customers in Portugal, specially at the scientific investigation departments in the Universities.
They enjoyed WANG as many of these machines were designed for such markets, with its ROM based BASIC featuring a lot of built in scientific functions like matrix operations for instance.

[jebem]

(10-11-2014 10:36 PM)Nigel (UK) Wrote:  Great pictures - thank you! I've got one of these too and I find it a great machine. It's compact, comfortable to use, good to look at and with enough memory to hold several useful programs at a time. It is 25 years old but it feels like it will last for ever. I'm not taking mine to pieces, though!

Nigel (UK)

Thanks for your input, Nigel.
This morning I managed to put it back in one piece, and it works nicely!

We are under heavy raining here, so the light conditions are not ideal for taking pictures.
Here are the photos that I managed to take after assembling the machine.

[jebem]

Memory test

(edited to add hyperlink to the Tandy service guide)
I found this memory test in one service guide for Tandy PC6 that looks similar to FX-730P and FX-780P CASIO machines (at least the specifications and schematic diagram applies to the FX-730P).

I tried it and it failed with ERROR1 (insufficient memory). Then I realized the program contains a few issues:
- P1 has got an extra line 101 that is never executed in the algorithm but it takes memory that makes impossible to use 904 cycles as defined in P0.
- P1 has a logic error in line 40. It is testing for "equality" when it should be testing for "inequality".

Procedure to test the memory:

1. Start by doing a hard reset so that the remaining memory capacity=7520 (do a MODE 1 to check it).

2. Type in the memory test programs P0 and P1.
Program P0 writes once to RAM memory.
Program P1 reads from RAM memory in a 4 times loop.

3. Execute program P0
Program P0 executes during 40 seconds and in the last instruction it jumps to Program P1 that takes about 140 seconds to execute if no errors are found (4 passes).
After execution, the remaining memory capacity=9.

Program P0
To type in P0, go into WRT mode (MODE 1) and select program area 0 (Shift P0)

Code:


10 CLEAR
20 C=904
25 DEFM C
30 FOR B=1 TO C
40 D(B)=B
50 NEXT B
60 $="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
70 BEEP 1: BEEP 1
80 PRINT "INPUT OK*";
90 GOTO #1

Program P1
To type in P1, select program area 1 (Shift P1)

Code:


  5 A=0
  7 A=A+1
 10 FOR B=1 TO C
 20 IF D(B)<>B THEN 100
 30 NEXT B
 40 IF $<>"ABCDEFGHIJKLMNOPQRSTUVWXYZ" THEN 100
 50 IF A=5 THEN 110
 60 PRINT A;: GOTO 7
100 PRINT "CHECK**NG**;: BEEP 1: BEEP 0: GOTO 111
110 PRINT "CHECK**OK**";: BEEP 1: BEEP 1
111 PRINT "A=";A;: END

Program P0 terminated execution and jumped to program P1:


Program P1 terminated execution with no errors:

[Nigel (UK)]

(10-11-2014 11:20 PM)Marcus von Cube Wrote:  If you can get hold of the cassette interface FA-3 my cassette io utilities might be a useful addition. http://www.mvcsys.de/doc/casioutil.html

Thank you for this. I don't have the FA-3 (yet!) but I do have the cassette interface for my TI-74. I look forward to trying out some of your programs.

Nigel (UK)

[david sanz]

Thank you for great pictures, and for the utilities too.

[jebem]

(10-14-2014 08:12 AM)david sanz Wrote:  Thank you for great pictures, and for the utilities too.

You are welcome, David.
I believe the FX-850P and FX-880P are more popular in Iberia than this smaller FX-730P, but I have chosen this one as it is less expensive to buy.
Prices for a FX-880P are very high these days, looking into eBay, or example.