Jump to content
Sign in to follow this  
Papalapa

Casio FX-9000P

Recommended Posts

This pseudo-computer has come into my hands through an friend who had it as a "decoration" at home. It seems that it was given to him by a friend who took it from a convent in a city near Barcelona city ¿?. I could not find out more and it is that with these old odds and ends I like to know if they have some history behind.

8ZvLihq.jpg

The first thing I did was open it to see if there was any evident damage inside and at first glance I have not found any. Even the RIFA paper capacitors that usually burst with time are intact. Electrolytic also and no other component is seen to be in poor condition.

It does not have the OP-1 interface with the cassette, printer and floppy disk outputs and I do not think it has ever had it because the connector is protected with a plastic strip fixed with screws. When removing the casing all the screws have made the typical "click" of when they were unscrewed for the first time, so I believe that no one had opened it to date.


ypjO4rM.jpg

Unfortunately it doesn't have any RAM or ROM cartridges in the slots either so it's the "bare" model I guess. I turned it on and unfortunately does not work. The “start beep” does not sound and the screen remains green and "flickering" and does not display any text. Pressing the keyboard also shows no change so I think it’s dead.

I have requested the diagrams from Casio Japan but they say they do not provide them so it will be hard to repair. I will try to start with the power supply, although as it is not very evident without diagrams it is almost impossible to know if it is working well. Later most probably I’ll replace all the capacitors and see what happens...

What I'm not sure of is whether a RAM cartridge is needed to boot or its internal 4K RAM is enough. If anyone has any information about the Casio, I would appreciate it if you could tell me.

  • Like 1

Share this post


Link to post
Share on other sites

From glancing around the operation's manual I get that this unit is just a glorified calculator. 

Share this post


Link to post
Share on other sites
Posted (edited)
3 hours ago, DragonGrafx-16 said:

From glancing around the operation's manual I get that this unit is just a glorified calculator. 

You're right, in fact it's only a "big" calculator, the first one that Casio made of this size.

Edited by Papalapa

Share this post


Link to post
Share on other sites

it DID have a functional BASIC though, from what I read in passing yesterday. (I was looking for a service manual for you, but came up empty, just found the user manual instead)  It could do monochrome graphics, and such.  As such, it should be theoretically possible to port some simplistic games to it.

 

You would need to get it actually working though.

Share this post


Link to post
Share on other sites
On 7/23/2020 at 7:15 AM, wierd_w said:

it DID have a functional BASIC though, from what I read in passing yesterday. (I was looking for a service manual for you, but came up empty, just found the user manual instead)  It could do monochrome graphics, and such.  As such, it should be theoretically possible to port some simplistic games to it.

 

You would need to get it actually working though.

Thanks for your interest. Yes, it has some sort of BASIC and memories like the Casio calculators. Also, by doing a simple program it can show graphics on the display.

 

Actually I'm dissasembling and cleaning all the parts and I probably will replace the electrolytic capacitors although they seem to be OK. The big problem is that I was told that this machine must have at least a 4K RAM cartridge inserted into an slot because otherwise do not turns on. I'm looking everywhere for this part but unfortunatelly seems impossible to found one.

 

Share this post


Link to post
Share on other sites
Posted (edited)

Might be needed to construct one out of perfboard, IDC header, and SRAMs?

 

Would need the BUS pinout though.

 

EDIT:

 

This site has pictures of the ROM and RAM packs. Sadly, no pics of the BACKs of the packs.

http://www.retrowiki.es/viewtopic.php?t=200030165

 

It is enough to get some general idea of the construction of the packs though.

Edited by wierd_w
Found pics

Share this post


Link to post
Share on other sites
Posted (edited)

Here is the datasheet for the CMOS RAM modules integrated on that card.

 

https://datasheetspdf.com/datasheet/TC5047AP-1.html

 

Looks like the card contained 8 of them, along with a lithium battery.  Some of the card edge should be derivable from the pics they provided, and from this spec sheet.

 

A more modern SRAM module might be useable with some effort.

 

This ram module is kind of strange, as it is natively 4bit memory. Since it is 1024/4bit, that makes each chip hold 512 bytes. It is likely organized into a high/low nibble configuration, but I would have to map out the card as best I can to be sure. That would make the card hold exactly 4kb. (edit-- quick looks suggests this is the case. The address lines are bridged between the chip pairs, left and right, suggesting simultaneous addressing of both chips at the same time from the card edge. This indicates an 8bit wide data read/write, split up with a high/low nibble between physical chips. With a redesign, a natively 8bit wide chip should work just fine.)

 

To use a more modern SRAM, you would have to take the low 4 bits from one chip, and the high 4 bits from its sibling, and combine them into an 8bit signal behind a latch, most likely.

 

Ask one of the EEs on here for details on that. I'm just a bench monkey. 

 

A more interesting offer would combine 2 card slots together with a bridge over the front-- combining a memory mapper, and a simplistic speaker setup. (Use the data IO for the second slot to drive the mapper and the sound chip, by mapping them as RAM in the second 4kb space. You could then control them with simple memory writes in that space. Your programs could live in paged memory of 4k pages stored in the first physical slot address area.) Since this thing does not have a real software library to speak of, it would give you something more fun to play with, as you could get paged 4kb pages, and a sound generator that way.

Edited by wierd_w
  • Like 2

Share this post


Link to post
Share on other sites
On 7/24/2020 at 8:11 AM, wierd_w said:

Might be needed to construct one out of perfboard, IDC header, and SRAMs?

 

Would need the BUS pinout though.

 

EDIT:

 

This site has pictures of the ROM and RAM packs. Sadly, no pics of the BACKs of the packs.

http://www.retrowiki.es/viewtopic.php?t=200030165

 

It is enough to get some general idea of the construction of the packs though.

Yes, in fact this user lives close to home and I already tried to contact him but it has been three months since it connects to the forum ¿?. Anyway I left a message from him.

Share this post


Link to post
Share on other sites
On 7/24/2020 at 8:51 AM, wierd_w said:

Here is the datasheet for the CMOS RAM modules integrated on that card.

 

https://datasheetspdf.com/datasheet/TC5047AP-1.html

 

Looks like the card contained 8 of them, along with a lithium battery.  Some of the card edge should be derivable from the pics they provided, and from this spec sheet.

 

A more modern SRAM module might be useable with some effort.

 

This ram module is kind of strange, as it is natively 4bit memory. Since it is 1024/4bit, that makes each chip hold 512 bytes. It is likely organized into a high/low nibble configuration, but I would have to map out the card as best I can to be sure. That would make the card hold exactly 4kb. (edit-- quick looks suggests this is the case. The address lines are bridged between the chip pairs, left and right, suggesting simultaneous addressing of both chips at the same time from the card edge. This indicates an 8bit wide data read/write, split up with a high/low nibble between physical chips. With a redesign, a natively 8bit wide chip should work just fine.)

 

To use a more modern SRAM, you would have to take the low 4 bits from one chip, and the high 4 bits from its sibling, and combine them into an 8bit signal behind a latch, most likely.

 

Ask one of the EEs on here for details on that. I'm just a bench monkey. 

 

A more interesting offer would combine 2 card slots together with a bridge over the front-- combining a memory mapper, and a simplistic speaker setup. (Use the data IO for the second slot to drive the mapper and the sound chip, by mapping them as RAM in the second 4kb space. You could then control them with simple memory writes in that space. Your programs could live in paged memory of 4k pages stored in the first physical slot address area.) Since this thing does not have a real software library to speak of, it would give you something more fun to play with, as you could get paged 4kb pages, and a sound generator that way.

Many thanks for your technical information but is too much complicated for me, I'm just an amateur. Anyway as I finally get the Service Manual here are the diagrams of the 4K and 16K RAM modules. Is there any sort of software that designs automatically the PCB by scanning the diagram?

 

16K.thumb.jpg.77242a46012ed8f1289891e25df3bc15.jpg4K.thumb.jpg.06c54f8e09163fe8b1baa3506e63958a.jpg

 

Share this post


Link to post
Share on other sites
Well, once finished the cleaning process this is the final result (compare with the photo in the first post):
 
zd22q1T.jpg

The process although laborious has been worthwhile. It consisted of disassembling all the parts to clean them and check if there were any damaged or suspicious components with the naked eye. Initially, I was planning to replace all the capacitors, but since I don't know if I willl find a RAM cartridge, perhaps this computer will never work 😭, so at the moment it continues with the original capacitors.

Here's the front view without the case, keyboard and cartridge cover.

 
BlIOX8Y.jpg

Cleaning the keyboard key by key was what took me more time.
 
Vg9p0ah.jpg

Detail of the open-door detector. If the cartridge access door is opened while working, a rather annoying beep sounds until you close it. The construction could not be simpler: two metallic plates that make contact when opening the door. Neither Reed relay nor optocoupler, this is reallly an old-electronics.
 
Uley3xm.jpg

It only has three PSBs, namely:

CPU board

 
wf2OF8b.jpg

Power supply board
 
gP3DDiU.jpg

Video card and tube
 
yHM6Av6.jpg

The "pet" naked 😄
 
kEczg2Z.jpg

Inside the silver rectangle in the upper left corner is an AC filter and a fuse. If it blowns this forces you to remove the casing. There are enough screws and is also necessary to remove the screws that fix the rectangle to the base to gain access to the internal fuse. How easy it would have been to put a fuse holder in the casing.

Finally I got the Service Manual and once everything has been assembled I have measured the three voltages of the power supply and some points on the PCBs and the values were all correct which confirms that the computer works well and if it does not start it is due to the lack of a RAM cartridge. Not having an oscilloscope, I have not been able to check the video signal or the memory timings.

I hope to get a RAM cartridge someday and see it work ...
 
 

Share this post


Link to post
Share on other sites
Posted (edited)

ooooooh.  That is nice.

 

You should be able to construct a wirewrap board out of that.

Since there is a 16k board, there should be enough address bits left over to drive a mapper chip on what otherwise acts like a 4k board.  I think a vastly improved board should be possible.

 

Do you have one for the cartridge slot itself?  I see that it is indeed an 8bit data bus, but the address line nomenclature is confusing. It looks like it has more than 20 bits of addressing though, so it should be possible to have over 1mb of ram installed. More if you use a mapper like I suggest. (a lot more.)

 

 

 

Edited by wierd_w
  • Like 1

Share this post


Link to post
Share on other sites

It seemed impossible but finally I found a 4K RAM cartridge and the FX-9000P is working now 👍

 

I'm surprised because the image on the screen is perfect. The TRC has enough bright and the characters are clean and without distortion nor vibration:

 

rpTkDNB.jpg

 

pojpA45.jpg

 

Now is time to read the manual and type the programm examples on it...

 

 

Share this post


Link to post
Share on other sites

Awesome, I wasn't familiar with this machine and loved your work and  ...

...

er..

 

"It seems that it was given to him by a friend who took it from a convent"

 

He stole it from nuns?????

 

;-)

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...