New Project on Obsoleted Part

New guy here, I am generally messing around with mechanical problems but this has me diving into the electrical world a little further than I would normally go.

So my project is a vehicle programmer which has a graphic LCD display that gives a lot of configuration options as well as gauges. It no longer works and is relatively common to go out. I contacted the manufacturer and they no longer support due to not having parts available. The backlight works but there is no information being displayed.

The display is a Displaytech 64128E which uses a KS0713 driver and is 128x64 but sometimes is listed as 132x65. This is no longer available. I have searched as far as my abilities can carry me and I am coming up with nothing as for a replacement. I bought a Displaytech 64128N display which uses a ST7565R driver and wired it into the old board using header pins and jumper wires. just to see if it would work. the good news is that it did light up and display the information... upside down and mirrored from right to left as well as really dark. So it lets me know that a new display does fix the issue of not having anything show up.

I am pretty stuck because I can't modify the code because it is an off the shelf unit that I'm guessing isn't able to be reprogrammed and if it was capable I surely am not. The board is 3v and the only LCD modules I can find that are 3v use some variation of the ST7565 driver. I need to find something that is compatible with the KS0713 driver, is 3V (unless I am able to power the board with 5V from a source other than the main control PCB?), is 128x64, uses 8 bit parallel interface. I would prefer the physical size to be around 2.5 wide or so but at this point just need something that works. I am not concerned with the fit being the same as the old one because I will plan to 3D print a new case for it.

I am at a loss right now, I don't play in this world much but I have a hard time believing there is nothing out there that i can make work. Is there not another display I can use that is compatible or is there not some sort of interface that would take incoming ks0713 communication and convert it ST7565?

Thanks everyone for taking a look. Hopefully I can learn a little more based on this.

Sorry, I looked and I guess this would fit better in the automotive section or the repairing electric product section.

what unit is it?

The programmer is an Edge Juice with Attitude, it is an older one that has the grey case with monochrome display. This is for the attitude portion which is a little module that goes in the cab and gives you the ability to modify what tune you are using as well as set safety limits for certain parameters and see up to 4 gauges that you pick.

Sounds like a real PITA. Did you see these two comments on the Displaytech site? **broken link removed** I did not log in and they may have gone unanswered (which is what I fear) but it might be worth a look see or a post of your own.

The first one was mine actually! I had not seen the second one yet. funny that it is recent. I saw another thread there that someone used an N to replace the E and found that it was mirrored, I knew this before I bought my 64128N but wanted to see in which direction it was mirrored and if there were any ways I could replace the data lines that would make a difference (remember I don't normally mess with this type of stuff so not sure if that is really possible).

Honestly I'm willing to try different LCD displays just to see if any of them will work but I can't find anything that is 3V and 8 bit parallel that doesn't use the ST7565 driver. That is why I had the question about whether I can use an external power supply for the 5V versions If I power the LCD with 5V the communication will still be 3V sent from the actual controller pcb if I'm not mistaken.

and yea it is turning into a PITA. I really want to fix it for a couple reasons 1 being not having to buy a new unit and the 2nd because it is really interesting. The problem is I am just not sure if there is a real solution - am I just chasing something that can't be resolved?

you could try something like this to try and use a 5v LCD's maybe.
or some other dc/dc booster/step up.

You can find small already assembled units with these functions on aliexpress , amazon and ebay.

I like those ready made ones and for a dollar or so that makes sense to buy one. I have a CV power supply but would be difficult to have all that setup at the truck for testing.

So if I use the 3v power for the LCD and run it through that amplifier to get 5v I assume I won't run into any issues with common right? That was one of my worries with using the power supply is that I would have to then tie my commons together.

I will look to see what drivers I can get in 5volt modules.

Thanks!

I'm not the best guy to advise on this type of stuff but if the 3v Supply can handle the added circuitry of the Boost converter and lcd youbshould be ok.

If the device is powered from the OBD Port you would probably be better off taking 12V-14v supply from where it comes in there and stepping down to 5V with something like a lm7805.

dusty20 said:

and yea it is turning into a PITA. I really want to fix it for a couple reasons 1 being not having to buy a new unit and the 2nd because it is really interesting. The problem is I am just not sure if there is a real solution - am I just chasing something that can't be resolved?

Click to expand...

You may try going in the other direction...that is, see what is out there with a KS0713 at 128 X 64, rather than trying to force a ST7565 . I have not looked extensively, but there may be something...this one is 'retired' as well but you get the idea.

That is one thing I don't know is if the 3V supply can handle the extra. Not sure how to tell other than try it.

this one doesn't use the OBD port it actually plugs into the PCM under the hood and has a little module that sits under the hood then there is a 5 or 6 pin connector that leads to the main PCB of the module that goes in the cab. I haven't checked the power coming in to the main PCB but know that there is a voltage regulator that has something like a -1.5 then common then +1.5 to give 3v across the outside legs if I read it right..

With character LCDs, the problem operating at 3.3 volts with a 5 volt display is that the voltage required on the Ve pin for contrast becomes negative.

Say it requires 1 volt when operating from 5 volts, so it's 4 volts less than the supply voltage. When operating at 3.3 volts, Ve still needs to be 4 volts less than the supply or -0.7 volts.

This works. I can't say how well or how long it will work in a real application.

DrG said:

You may try going in the other direction...that is, see what is out there with a KS0713 at 128 X 64, rather than trying to force a ST7565 . I have not looked extensively, but there may be something...this one is 'retired' as well but you get the idea.

Click to expand...

Yea I would love to find something else with a KS0713 but I haven't found anything. I can't find anything that appears to be a ks0713 chinese knockoff, I did find some 5V LCD modules that claim KS0107 compatible so that may be closer. Even some of the sights will show you replaced with xxxxx then you follow that and it shows another and then eventually just ends. I have had some of them lead to an ST7565 driver - I guess that works if you can modify the code to mirror the image.

JonSea said:

With character LCDs, the problem operating at 3.3 volts with a 5 volt display is that the voltage required on the Ve pin for contrast becomes negative.

Say it requires 1 volt when operating from 5 volts, so it's 4 volts less than the supply voltage. When operating at 3.3 volts, Ve still needs to be 4 volts less than the supply or -0.7 volts.

This works. I can't say how well or how long it will work in a real application.

Click to expand...

interesting. This is my ignorance here but what happens when the VE pin is negative - do you mean it will work with it negative or that I need to make it positibe? I will look at the schematic again and see if I can understand a little better.

Looking at the diagram I am not seeing VE? Would that be interchangable with something else on there?
This is the pinout for the 64128E with the KS0713 driver for reference.

JonSea said:

With character LCDs, the problem operating at 3.3 volts with a 5 volt display is that the voltage required on the Ve pin for contrast becomes negative.

Say it requires 1 volt when operating from 5 volts, so it's 4 volts less than the supply voltage. When operating at 3.3 volts, Ve still needs to be 4 volts less than the supply or -0.7 volts.

This works. I can't say how well or how long it will work in a real application.

Click to expand...

What do you think about trying to add in a 5V dc/dc step up to power the 5V LCD ?

Actually wouldn't a DISPLAYTECH 64128COG be close? There are a few around that seem to be available like here https://www.ebay.com/itm/DISPLAYTECH-64128COG-CCTW-DISPLAY-128X64-R4S5-7B4-/302324784180 or **broken link removed**

I just spoke with someone at focusLCD on their live chat deal and they stated I could use an S61713 or the ST7565 but they would require that the firmware be modified so that it will work. How involved is that?

DrG said:

Actually wouldn't a DISPLAYTECH 64128COG be close? There are a few around that seem to be available like here https://www.ebay.com/itm/DISPLAYTECH-64128COG-CCTW-DISPLAY-128X64-R4S5-7B4-/302324784180 or **broken link removed**

Click to expand...

That is interesting, I don't know what the COG is? so would this essentially not have a driver? Would I connect directly to the terminals on the display and forego the display pcb?

dusty20 said:

That is interesting, I don't know what the COG is? so would this essentially not have a driver? Would I connect directly to the terminals on the display and forego the display pcb?

Click to expand...

COG=chip on glass. It seems to take the original KS0713 controller. It *may* be functionally identical to the E which is what you have. Here are the datasheets for Displaytech **broken link removed** which you have and the **broken link removed** - you can compare them for compatibility (I have not done that carefully).

The one on the right is the 64128E and the one on the left is the 64128COG. I didn't see the LED but I'm sure I can figure that out. The spec sheet says refer to KS0713 all over the place. I knew that COG was chip on glass but wasn't sure what that meant compared to something with a driver IC. Also, since it didn't state a driver I wasn't sure how it functioned since the others use the driver to decipher the code and relay it to specific pixels.