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Casio FX-602P - Printable Version

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Casio FX-602P - Geoff Quickfall - 08-29-2015 07:18 AM

Great little cal. Just got one at the flea market for five bucks!

Problem is, continuous memory seems to be non existent. Those familiar will know memory and program lines are interchangeable on a one for eight basis.

So by selecting MODE .20 I get 20 memories and 512 fully merge able program lines. Unfortunately when I turn the machine off the programs erase and I get 83 memories and 000 lines of program at next turn on.

Any ideas? I have cleaned internals, checked connections, can't find any caps for memory retention although I suspect it actually taps into the batteries while the calc is off.

Help, I would like to get this running as I have a cassette deck and fa-2 interface. Guess I can always turn it on, load it from the cassette deck but the treat about this calc is it is only a cm thick and I don't want to lug around the rest of the paraphernalia.


RE: Casio FX-602P - Paul Dale - 08-29-2015 08:08 AM

No idea what the problem is here.

My FX 602P died in a weird and wonderful way after several years of heavy use Sad My printer and cassette interface were lost not long after.

I do still have the book of programs I wrote for it which I've been meaning to scan.

A great calculator, easily one of the best of its vintage even if it isn't RPN.


RE: Casio FX-602P - Geoff Quickfall - 08-29-2015 08:11 AM

Thanks for the response Paul.

Yes, even though not RPN, pretty powerful for 1981, and thin!


RE: Casio FX-602P - Paul Dale - 08-29-2015 08:15 AM

And fast.

Surprisingly fast for the time.


RE: Casio FX-602P - G. Cook - 08-29-2015 09:56 PM

I have a Casio FX-702P. I always thought the 602P & 702P were functionally similar.
Guess not. On the 702P, the "mode" is not fractional, only 0 thru 8. Mode 0 is "RUN", no memory is shown. but numbers can stored in all letters of the alphabet. In mode 1, "WRT" the available memories are indicated. The memories are 0 thru 9 with a max of 1680 bytes. It is always available and all saved programs are kept after turn-off. Did you get a 602P manual? I can't believe the 602P was designed with volatile memory.
Good luck.

RE: Casio FX-602P - Paul Dale - 08-29-2015 10:28 PM

The 602P didn't have volatile memory. This unit has a defect. The 501P, 502P and 601P are all in the same vein as the 602P, just with less memory and in the 50xP cases, no alpha. The Japan only 603P adds a lot of memory but doesn't change the operation much otherwise (I've never seen one of these unfortunately).

The 702P is completely different device -- it uses BASIC, the models mentioned above are keystroke programmables.

- Pauli

RE: Casio FX-602P - Marc van Lemmen - 08-31-2015 11:25 AM

If you do not turn off the calculator it will automaticly shut down, is memory then also lost ?
I recently bought one with some 'strange' problems due to corrupt data. I was not able to divide the memory for programs and data. After completely cleaning all the programs and memory it worked again.


RE: Casio FX-602P - Geoff Quickfall - 08-31-2015 04:42 PM

It is bizarre to say the least.

All programs wiped (INV MAC in PCL mode 3)

On occasion it will remember, on others it drops all an resorts to default mode F000.

Cleaned board, contacts. Re soldered suspect joints. All to no avail. Defeats the purpose of having 10 programs and 512 lines unfortunately.

Thanks for the suggestion though.


RE: Casio FX-602P - Marc van Lemmen - 08-31-2015 09:38 PM

Too bad ! When I remove the batteries for a while it also starts with 000 steps for program memory. Looks like your calculator totaly loses power after switching off.
Can you see if the calculator is changed for higher speed ? Maybe higher speed in combination with not to fresh batteries causes problems.


RE: Casio FX-602P - isanchez - 09-01-2015 01:02 PM

I have a FX601P, and I have bought the printer, very cheap, new in the box. The thing is that when i try to print the screen, followng the instrucions i.e. "123456E99" INV save INV EXE...I get two messages: first DF 000 and then OP ERROR...nothing is printed...the same behavour without the printer connected...maybe I am introducing something wrong...I can't find the meaning for these messages in the user manual (neither in the 601 nor the printer)



RE: Casio FX-602P - Geoff Quickfall - 09-01-2015 02:14 PM

New batteries, and no mods to the circuit board that I can see. After testing it some more, it doesn't care what I set by MODE .xx The result is either F000 or surprisingly F512. Both defaults, but at either end of the spectrum.

Haven't got a printer, just the tape/printer interface FA2 so can't help Ignacio.

Cheers all, Geoff

RE: Casio FX-602P - Marc van Lemmen - 09-01-2015 03:12 PM

Maybe it's realy broken, I'm out of options. Too bad Sad
I once had a FX-602P with a faulty memory, 3 Min06 -> Mr06 returend 1. It never returned to normal. Also some sort of memory problem.
I have schematics for expanding the memory size of your FX-602P to +/- 6000 steps if you are interested.

About the printer, I have one and the message DF 000 / OP Error only occurs when the printer is not connected, maybe a broken cable ?


RE: Casio FX-602P - isanchez - 09-01-2015 04:04 PM

Thanks for your comments.
The printer works fine. I have tested it right now with a 502fx...it is not documented but works fine also with this model. It doesn't need the inerface. Probably the problem is in the calculator. I am going to check the batteries...and the contacts
Thanks again

Kind regards


RE: Casio FX-602P - isanchez - 09-02-2015 06:27 AM


like always...you were right: it works fine with fresh batteries. The thing is that there is no low battery indicator. As soon as I have replaced them, it worked fine: no error messages and the printing is fine.
I find these two calculator families FX50x & FX60x were probably the best produced by Casio ever. They were designed to compete with Hp41 series. The best argument probably was the low price, and you get alphamumeric (60x), programmable, calculator with priting and storing capabilities. I think they are nowadays the most expensive and wanted Casio calculators from the 80's.

Thanks and kind regards


RE: Casio FX-602P - Marc van Lemmen - 09-02-2015 11:31 AM


The FX-602P is my favorite calculator and is one of the few 'old' calculators i realy use, next to the HP-67. It is not to large, thin and the batterie life is very good.


RE: Casio FX-602P - ijabbott - 09-03-2015 05:06 PM

I had the older FX-502P, which had some interesting, exploitable display hacks. It was my pride and joy in my final year of high school (back in 1981), but it died about 15 years ago (probably a dodgy capacitor or something).

RE: Casio FX-602P - hp41cx - 09-03-2015 07:33 PM

Casio cheap :-)

RE: Casio FX-602P - Csaba Tizedes - 10-11-2019 04:22 PM

Is there any experience about which voice recorder applicable to FA-1 and FA-2? Any advice helps.


RE: Casio FX-602P - Maximilian Hohmann - 10-11-2019 04:59 PM


(10-11-2019 04:22 PM)Csaba Tizedes Wrote:  Is there any experience about which voice recorder applicable to FA-1 and FA-2? Any advice helps.

You mean a cassette recorder as was originally intended to be used with that device?

If so, then it ideally must have mono connections using 3,5mm plugs for in and out and a remote connection with a 2,5mm plug. "Remote" turns on and off the recording. It probably works also without the remote connection.

I still have one from Sharp (similar to this: https://www.hifiengine.com/manual_library/sharp/rd-620d.shtml) which I bought for my Sinclair ZX81 back then. I tried it also with some Sharp and Casio BASIC programmable calculators in my collection.
The main problem with those old devices are the rubber parts: Drive rollers and belts. Over the years they get brittle or sticky (just like the "gummy wheels" inside HP card readers). They can be easily replaced, but parts are very very difficult to find.

One thing worth trying would be to connect the FA-1/2 interface to the audio port of your computer and see, if it can't be used with an audio recording software (on my Macintosh I have the free software "Audacity" for that, no idea what Windows or Linux users would prefer). I have never tried it but there is no reason why it shouldn't work. It's maybe not the historically correct way of doing things, but who cares...


RE: Casio FX-602P - Dave Britten - 10-11-2019 05:03 PM

(10-11-2019 04:22 PM)Csaba Tizedes Wrote:  Is there any experience about which voice recorder applicable to FA-1 and FA-2? Any advice helps.


I use a Tandy Computer Cassette Recorder with my FA-3. It works quite well, and is in fact the only recorder I've been able to make work with it, out of a handful of cassette and digital recorders. I suspect it's got something to do with either the strong line-level output of this recorder, or mono vs. stereo jacks.