Wiring info needed - CU20026SCPB-t23a
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Author:  prof_porridge [ Thu Apr 28, 2005 0:53 ]
Post subject:  Wiring info needed - CU20026SCPB-t23a

Hi, I have a 20x2 VFD labelled CU20026SCPB-t23a that I need help connecting. I have looked at the diagrams for the other t23a models that are avaible but they don't help me because my unit has a 26 pin connector and no separate power connector. The unit seems to have the same IC's as other noritake t23a's, with the SED2000 + the sed2032 as well as a motorola chip.

Does anyone here know how I can hook this up to my pc's parallel port?

thank you,

Author:  Henri [ Tue May 03, 2005 23:56 ]
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Hmm sounds like you might have some less common version of the display there. Have you tried looking for any Noritake display datasheets that might be similar in some ways ?

Author:  prof_porridge [ Wed May 04, 2005 1:05 ]
Post subject: 

Yes I have looked at the datasheets on the noritake website. Some models seem that they would be very similar but none of them have the 26 pin interface.

This unit is a replacement for the VFDs in the 'Millenium' payphone. The ribbon cable goes directly from the display to the pc board inside the phone... do you think that this VFD might be a custom-designed model that plugs directly into a 'parallel port' type interface on the mainboard?

I'm going to try emailing noritake for the pinout. Do you think that it might be the same for the first 16 pins as the other T23 models, and that the rest of the pins are for GND and +5V?

Author:  coorz [ Wed May 04, 2005 8:06 ]
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How about a pic of the backside? Perhaps it's the same display but indeed with a different connector. I doubt that though...

Author:  prof_porridge [ Wed May 04, 2005 18:42 ]
Post subject: 

Yes, that would be a good idea. When I get home from work I will take a picture and post it here.

Author:  Henri [ Fri May 06, 2005 0:08 ]
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Ok so based on your description it is some custom model. In that case the pinout might be almost anything.

That motorola chip you mentioned, what is the model number ?

Author:  prof_porridge [ Fri May 06, 2005 4:23 ]
Post subject: 

Henri, I'm not sure the chip is a motorola anymore. This unit has the chips placed under the glass which makes it very hard to identify them.

I managed to make out the numbers on some of the chips. Here it is:

-Chip 1-


The chip is actually labelled 'IC4' on the pcb but i have called it chip one because if you follow the circuit traces from the connector, they lead to this chip.

-Chip 2-


-Chip 3-

Cannot read the markings on this one but the PCB is marked 'IC1 SED2000' at this location.

I have some pictures that I will post as soon as I upload them. Thanks for the help so far guys!

Author:  prof_porridge [ Fri May 06, 2005 4:34 ]
Post subject: 

Here is the front of the VFD. It's hard to make out in the picture but the model number is on the bottom left (cu20026scpb-t23a).


Here is a close up of the single connector. You can see that it is a 26 pin connector (sorry about the flash)


Here is the unit from the back, note that all the components are on the front of the VFD, under the glass.


I have a few more pictures at that are similar to the pictures above that I didn't post to save bandwidth.

Author:  Henri [ Fri May 06, 2005 9:43 ]
Post subject: 

M38802M2 sounds like a Mitsubishi part number then. Mitsubishi parts are used in many Noritake products.

This isn't the first time I'm seeing some part number that looks like a standard Noritake part but still could be only a small custom series.

CU20045SCP-T23A uses M37450M2-277FP which seems to be a 8-bit microcontroller. ... 272FP.html

For M38802M2 something can be found here ... 8802m2.pdf
which is saying that it's also a 8-bit microcontroller.

As they are microcontrollers there could be some custom program in it. Maybe if lucky it would be similar than in standard Noritake products and if the pinouts between the controllers are similar enough you could make a guess and try.

Anyway best way would be to get the datasheet for the display somewhere, which can be a bit difficult for custom products though.

Author:  prof_porridge [ Sat May 07, 2005 5:08 ]
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Ok, I am trying to guess the pinout of the connector, and it isn't that easy :cry:

It looks to me like most of the data signals are on the odd-numbered pins (just the bottom row) and that the even numbers seem to be mostly for the power. As you can see in the picture, pins 22, 24, and 26 are all interconnected and appear to be the ground.


I have also marked off pins 2, 4, and 6 which seem to be where +5 v is connected since it looks like the are connected on the other side of the pcb. I checked by testing continuity from the pins to the leg of the large capacitor marked with a +.

The 9 pins in the black rectangle (1, 3, ..., 17) all lead directly to the M38802M2, so I think that they would be the 8 data pins and one other, enable perhaps?

The pins I have marked A, B, C, and D also lead to the same chip, but by different paths. Any idea what these might be?

Does this sound like it might be right? I really have no experience with displays like this. What connections do I still need to account for?


Author:  Henri [ Tue May 10, 2005 18:16 ]
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If looking at the CU20045SCPB-T23A datasheet the pins would be D0-D7, /WR, /CS, Sin (serial) and BUSY.

So that would make 4 pins beside the 8 datalines. But of course this display might have different interface and there could be /RD too or some other pins. But then the problem is trying to guess what goes where. Maybe if a datasheet for M38802M2 was available it could have pins with similar names.

Author:  Aleks [ Tue May 17, 2011 1:32 ]
Post subject:  Re: Wiring info needed - CU20026SCPB-t23a

I'm very sorry for posting in this old thread, but I'm in the need of the CU20026SCPB-t23a datasheet.

Can someone please provide it or point me to somewhere where I can find it ?

Regards and all the best,

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