Casio PB-700 and FA-11 Printer & Tape Recorder
I recently acquired an New Old Stock (NOS) Casio PB-700 with the FA-11 printer & tape recorder and an OR-4 memory module (4KB) from an eBay seller for a very cheap price. I know sometimes it’s fun to play with old technology, and this article will share some of my findings.
The PB-700 packaging is still intact ever since 1984:
And so is the printer box. The left one is the paper cover, the right one is the plastic container for the printer and accessories:
The user manuals for the two units:
The scanned PDF copy can be downloaded from here (for PB-700) and here (for FA-11). More user manuals of similiar early computers can be downloaded here
Exploring the PB-700
However, when I first powered up the set, it did not work properly. The PB-700 LCD was not displaying properly (perhaps due to aging). The computer still seemed functional and responded to basic command such as BEEP.
The FA-11 did not seem to power up at all. Perhaps the rechargable battery inside the unit had died due to aging. I tried to leave it charging for 2 days and it still could not turn on. The AC adapter provided 8.5V, way beyond its specifications of 6V DC output. Some research suggests that the AC adapter is unregulated, so it may produce higher voltage when no load is applied. Whatever it was, the seller was nice enough to exchange a working set for me.
This time everything is working – the LCD is fine and the printer is able to print, although with difficulty (more on that later). The following photo shows the complete setup:
My first “Hello World” program on this device works fine, so I attempt to write a program to plot the graph of a sine wave. Luckily a sample is given in the user manual:
Take note that the line numbers must be keyed into the actual program. They are not there just for demonstration. If you don’t key in the line number, many control commands (FOR, WHILE, IF) will not work.
It took me 10 minutes to key in this program and modify it slightly to display the graph title. Here is the execution result:
If you have never worked with early computers before, you”ll be surprised at the execution speed. The following video shows you why:
It takes 20 seconds to plot the graph – you can literally see every pixels being drawn. Nowadays, modern computer can plot this graph in less than a second.
Testing the FA-11 Printer
My next try is to use a FOR loop with LPRINT to repeatedly print text to test the printer. The following video shows the printer in action:
It takes around 3 seconds to finish printing a single line of text, a slow speed thanks to the pen assembly.
There are a total of 4 pens, supporting 4 different colors. The horizontal stepper motor moves the pen assembly from left to right, a rotor will rotate the assembly to select the correct color, and a pin will push the required pen, touching the paper thus “plotting” the required text onto the screen. A very sophisticated piece of engineering! Unfortunately, this is an open-loop system – the printer does not have any ideas whether the pen assembly is correctly aligned. After a while, the pen assembly will no longer be calibrated causing the pen not to touch the paper and nothing will be printed. When this happens, I will have to stop the printing process and re-align. With care, the re-alignment can be done during printing when the pen assembly moves closer to the right.
Here is the printer output:
Because the pen slightly touches the paper when it moves from right to left during a carriage return and line feed, every line is underlined! The spacing between the lines is also not exactly equal thanks to the paper roller which doesn’t care what happens to the paper during rolling. I am not sure if this is how the quality is supposed to be. Or perhaps I have an old unit…
The output would have looked like this when the plotter was new (thanks to damaltor for posting the photo):
Tape recording & playback
My next try is to use the tape recorder to read and write programs:
The tape is just the normal cassette tape, used in the days of the Walkman. Program are stored as audio tones, with different tones for binary 0 and binary 1. Some more information is available here.
This is a closer look at the cassette tape. Interestingly, the tape comes with the erase prevention tab removed (thus the REC button can’t be pressed). I have to put some paper in the holes to allow recording.
Using the SAVE command will store the current program as tones on the tape, to be retrieved later. The recorder plays the tones to be recorded during the process, making a sound similar to a dial-up modem connecting. Download the audio here.
Unfortunately, I am unable to read back the saved program using the LOAD command. The command simply hangs and I have to stop it. The recorder plays the tones of the saved program, which sound significantly different from what was recorded. Perhaps the audio head has malfunctioned due to aging, or the magnetic tape has degraded over the years and no longer suitable for recording.
Hope you will learn something new about old computer technology after reading this article. Except for having fun while testing it, the unit is not very useful to me. I have not even figured out how to insert a new line when editing a program (it’s not mentioned in the manual). Therefore, after writing this article, the unit will probably soon be put in my closet.
More technical information about the Casio PB-700 computer series and accessories is available here
MP3 isn't a suitable format for archiving the sound data. You'll need a lossless format such as WAV. I've written software to encode and decode such a recording from and to text. Write your programs on the PC and send them to the PB-700.
See here
Marcus, thanks for your useful link, but my link to the mp3 audio clip is just an illustration of how it sounds like. The original data is not meant to be decoded from that mp3 recording![:)]( "Smile")
I was thinking along this line. It was just an opportunity to tell you about my utilities. It's the kind of reverse engineering you seem to be occupied with. More on the software side of things but that's my profession. I own a soldering iron but most circuits would prefer to run away from me if they could.![;)]( "Wink")
Marcus, your website is great with a lot of useful utilities. Will try out some of those on my PB-700 when I have the time to.
I work in the software industry but hardware is my hobby too![:)]( "Smile")
Hi!
i own one of those devices too, and i guess that your plotter/printer is broken. On my device, the pen never gets disaligned and works well even for long jobs. Also, on my printer every line is NOT underlined.![:)]( "Smile")
damaltor
Hi damaltor, thanks for sharing with me. I have always been hoping to fix the unit to print properly when I have the time to![:)]( "Smile")
Here you can see a plottet source code from my plotter.
http://dl.dropbox.com/u/60911662/12050006.jpg
Nice printout, thanks for the photo![:)]( "Smile")
There is a small plastic lever on the right end of the printer roll, that controls the pressure on the pens. It is pushed by the green solenoid that you see on the right of your picture showing the pen carriage. That small lever tends to break, and a small drop of crazy glue (the gel type) could solve the problem, thus improving your printing. There should be no need to make adjustments. It's nice to see it working. Thanks!
Hi Dark, thanks a lot for sharing. I will have a look at the unit again and see if your suggestion helps fixing the problem![:)]( "Smile")
hello,
im in dire need of such gadget for my work? do you have any idea where I can find and acquire PB-700 and FA-11? how about the PB-100? Do you have any consideration of re-selling the whole unit to me? im interested. my email is metierra64@yahoo.com.ph. my contact number is +63-9272206926.
thanks for sharing.
MET
@MET: Try searching eBay (http://www.ebay.com), occasionally there may be some sellers putting up their own electronics stocks for sale. Good luck!
necesito el manual en español del FA-11 por favor
I have a Casio PB700 + FA-10 + CM1.
I have following phenomenon. If I operate FF or REW on tape after 15 or 20 counterstep automaticly it stops.
If a try to save my program to tape, recording does start but after 2sec it stops.
See attached video:
https://youtu.be/y9t7Su4Y4f8
Any idea?
Can you check the condition of the cassette deck and of the tape and see if it can move freely? Try to operate the cassette deck by itself without writing any codes and see if recording/playback will stop after a while.
Although there might be mechanical issues with the cassette deck itself, I believe the issue is caused by the tape deck wrongly sensing the end of file marker and issuing the STOP command. According to the FA-11 manual, the tape will automatically stop after data has been fully written. However, from your video, the tape stops while the tone continues to play. This might be due to some electrical issues (leaky caps?) or it could be due to poor tape quality causing the tape deck to misinterpret the end of file marker. Try to clean the head with alcohol. Also, use a known good cassette tape and see if things change.
thanks your reply.
I have another phenomenon as well. If I just REV or FF casette after 15/20 counter steps it stops. I think it hasn’t anyting to do with PB700 and docking station. So REMOTE thing should be irrelevant.
I have tried with another or without casette. The REV/FF issue is the same. Save I have not tried without casette.
Is it possible the FA-10 docker has problem? Or only the CM1 module works badly? Electrical contact? But it starts..
Does have CM1 some motor assistant feature?
Any ideas are welcome.
Hello,
this report inspired me a last year to find an Casio FA-10. A few weeks ago I got one – yea-yea.
but – it looks the “line feed” is not working well.
I tried to run the FA-10 plotter self-checking (plotter ON and simultaneously press FEED) . The result you see in the picture. I did the following 4 print-test. Pictures and short video are published https://photos.app.goo.gl/vSRfARt7onZHm3fm6
print-test 1)
FA-10 plotter self-checking (plotter ON and simultaneously press FEED)
it was the first self-test, but wrong “CR” Carriage Return … the plotted Circle moving to the right of the paper.
During plotting (not finished) I switched of the Plotter (power OFF button).
print-test 2)
repeat again the FA-10 plotter self-checking (plotter ON and simultaneously press FEED).
you see Line Feed not working well
print-test 3)
Interface-Checking (FA-10 manual, program page 14
Line Feed not working well
print-test 4)
simple program execution at PB-700 to plott a circle (repeated 2 times).
After normal swiching on the plotter and just try the FEED button to move the paper, does not work. Looks somehow FA-10 does not know anymore the proper function of FEED.
(result: It is not woving the paper role to transport the paper.) Instead of this, the plotter head is moving to the left.
I recorded a short video and uploaded a picture.
https://photos.app.goo.gl/vSRfARt7onZHm3fm6
Is there somebody – who know what is the problem and how to solve it ?
Best regards Hagen
HI Hagen,
From the videos I think your paper roller is not working properly. There are usually two pieces of rubber on each side of the roller which are designed to “grab” onto the paper and “roll” it up by one line when the printer receives a line feed command. Can you try to feel the rubber – it might have become smooth over the years and is no longer able to “grab” the paper. If so, try to use coarse sandpaper to give the roller a more textured surface, and it should be able to grab paper as intended. This is the most likely scenario.
Another reason could be that the roller stepper motor is not working. If this is the case, you will notice that the roller is not moving at all following a LINE FEED command. The stepper motor might have become sticky over time and unable to move. If so, you might want to try some lubrication oil and see if it will improve.
Let me know if you manage to fix it.
Thanks for your hints. I opened the FA-10 to get better view at the plotter and made new pictures and movies. All availalbe at the same link https://photos.app.goo.gl/vSRfARt7onZHm3fm6
The plotter has pieces of rubber left and right side. Instead has left and right metal peaks at the end of rubber role. It´s the reason why the paper has holes, if moving is working.
Left and right stepper motor running well. But each gear at the motor shaft (Motorwelle) were procken and not strong mounted at the shaft (Welle) anymore. See videos left or right _before_fixing*.mp4
I put one drop of glue in front and behing of broken gear direct at the shaft (Welle) to strongly fix the gear at the shaft. I did it at left and right gear. I black painted left and right motor shaft to show the movement of motor shaft (Motorwelle) and to show if gear is strong fixed and moving or not.
See videos left or right _after_fixing*.mp4
Result: Both gears strongly fixed at motor shaft. Both stepper motors working. Unfortunately this did not solve the problem. But paper still not moving.
Is the somewhere a mechanical problem inside the metal box around the rubber role ? Is there somewhere any detector which maybe causes the problem ?
Hmmm , need further investigations … maybe I need to open the metal box around the rubber role ? Maybe dangerous ?
Somebody any idea ?
Hi,
When I tried it, line feed worked fine with normal paper (at least on my printer). You can see from the videos in the article. Paper with holes on either side, like those meant to be used for dot matrix printers, will work better, but are not needed for basic operation.
Can you try to manually (but gently) pull the paper through the printer and see what happen? If you manually rotate the printer roller bar, does the paper move? Also does the paper roll, when installed, feel tight enough or does it feel loose? If the paper roll is loose, the roller will not work to perform a line feed.
On my unit there is no sensor for the line feed that I can find. These things are very simple, I still think it is a straightforward mechanical problem and can be fixed if you figure out how the mechanism is supposed to work. You can try to open the metal box around the rubber role, but just be careful, it will be quite hard to put in back together. If you do open it, take some photos first
the mechanical case still open and can not be solved now. Need further investigation.
Casio FA-11 replacement of orginal accu:
The original accu “P-17N-5A28″ 6V 1650 mAh is not chargeable any more. It was blowing up.
Does anybody has an idea, which complete replacement accu I can buy somewhere ?
Or several accu I can purchase and buid me own replacement accu ?
Best regards Hagen
Hi Hagen,
For the rechargeable battery, P-17N-5A28 6V @ 1650mAh, you can replace it with 4 x NiMH rechargeable AA cells in series. Try to pick cells with capacities similar to the original, e.g. around 1600mAh. Throw away the old battery pack but keep the connector, and wire it to a 4xAA battery holder. It should work fine.
Thanks !
Something like this 2/3A formfactor should also work, right ?
https://www.batteryjunction.com/tenergy-1600-23a.html
I thought, if the original Casio power supply AD-5480 is connected to FA-11, the plotter should work (at last move the pen-holder). But this is also not the case.
Maybe the accu P-17N-5A28 6V @ 1650mAh is NOT broken, but something else. Because I measured 6.6v with my Multimeter between (+) and (-) of all cell at the original accu P-17N-5A28 6V @ 1650mAh (Casio FA-11).
Has anybody the cicuit diagram of Casio FA-11 and Casio FA-10 ?
Maybe an electronic friend can then help me to find the problem at the PCB .
I have this issues at my Casio FA-10 and Casio FA-11.
Best regards Hagen
Hi,
It is possible that the plotter is designed to take power from the battery, and the power adapter is meant to only charge the battery. Without a functional battery, the plotter would not operate due to lack of power. In general, circuits which require peak currents higher then the capacity of the power adapter, or require “cleaner” (without electrical noise) power quality are usually designed this way. Most cell phones, for example, require a functional battery to work, even if a charger is connected, because a typical USB power adapter @ 5V 1A will not be enough to power the internal circuits which may need 2A or more. On the other hand, most laptops can work without a battery connected, because their power adapters usually provide enough power.
Try to measure the voltage again with a multimeter in LoZ (low-impedance) or battery tester mode. If you do not have one, connect a 1kOhm resistor in series and measure the voltage instead. This is to make sure that the battery voltage will not drop under load. From experience, old batteries may appear to provide sufficient open-load voltage (which is what a normal multimeter measures), but their output voltage will drop significantly with a load connected.
If you suspect the battery is an issue, try to feed 6V from 4xAA cells directly into the battery connector, taking care of polarity, and see if the plotter would show any signs of life. If it doesn’t, check the PCB to see if there is any fuse (which may or may not be obvious as SMD fuses can be hard to spot). If there is one, it might have blown. A paper jam might have caused an overload and blown the fuse – the plotter is very simple and has no mechanism to prevent these kinds of failure conditions.
The 2/3A 1600mAh 1.2V NiMH battery you choose is great. Also take a look at the charging curve a typical NiMH cell here https://newbedev.com/why-do-three-series-connected-1-2-v-nimh-batteries-read-4-16-v-when-charged . A reasonably charged NiMH cell will measure around 1.4V to 1.45V, so with 4 of them your battery pack will measure around 5.6 to 5.8V, which should be good enough.
Let me know your progress.
The FA-10 plotter is working (pen holder moving), if I connect 4x 1.5 AA batteries (total 6V). The test with measured voltage of 4x 1.27V NiMh-accu fail, because the total voltage 5.08V is to low. I will fully charge them and also purchase a 5th NiMH accu (then have 5x 1.2V total 6V) and test again.
The FA-11 plotter is not working, if I connect 4x 1.5 AA batteries (total 6V). Sofar I did not sear a any fuse.
Instead I measured the power the all 13x cable and compare with working Casio FA-10.
At the 3 cable (see the picture in this link https://photos.app.goo.gl/D74Z8cGUnNBEARpVA) I measured a voltage of 6.x V (plotter OFF) and 6.x V (plotter ON).
This is different from working FA-10. At the same color cable I measured a voltage of 6.x V (plotter OFF) and 1.x V (plotter ON).
I guess, still the details circuit diagram for further detailes measurements. But who has such a circuit diagram of Casio FA-11 and/or Casio FA-10. I guess the are very similar (just other mechanical tape).
A fully charged Ni-Mh cell will measure around 1.45V, with 5 of them the voltage can easily reach 7.25V, so you might want to be careful. With 4 fully charged cells the voltage should be around 5.6V to 5.8V, likely sufficient for operation. Although I suspect there is a wide tolerance for input voltage (there might be, for example, a voltage regulator in the circuit which drops the voltage down to, say, 5V), so 5xNi-Mh cells would probably work fine.
Can you use your multimeter in current mode and measure the current consumption of the FA-11 when 4×1.5 AA batteries are connected? If no current passes through the FA-11 at all, you can suspect a blown fuse or broken PCB trace somewhere. If the device consumes current but does not seem to operate, there might be some electrical issues, in which case you might want to start by measuring the voltage across the pins of the NEC D78C066 chip shown in your photo. There should be 5V or 3.3V somewhere, and likely a clock signal, which can be seen on an oscilloscope. Unfortunately, I could not find any datasheet for that chip online.
This site http://www.pisi.com.pl/piotr433/ has some circuit diagrams for vintage Casio devices, including the FA-6. I could not find any diagram for the FA-10/FA-11.