LCD Pinouts

Today I was at my friends shop. He recycles all manor of Electronics equipment, printers, computers, projectors etc. Today he was tearing down several large printers. Since I do all his network maintenance he pretty much lets me have what ever I want. I have recently been collecting all his NEMA stepper motors and the DC motors that some of these printers have. Some of the DC motors have rotary optical encoders and I managed to pick up three of them last week. I have another post on analyzing the pinouts of those motors.
Today I picked up two lcd boards. One is a 18 X 2, the other is a full size screen, about 4 X 10 inches, but that board is for another day.
I was wondering if anyone has found a way to analyze an LCD board to determine the correct pinouts. I have wired 16 X 2 boards and OLED boards successfully, but never tried to use a salvaged LCD screen. Thought it might be a good learning experience. I have to assume that most wiring on these is pretty much standardized, unless printer companies make their own boards.
Here are some pictures of the board(s). Yes I was able to salvage the control board along with the lcd board. Thought I might be able to use it in some way.
It appears that the ribbon cable (11 pins) connects the control board to control options on the printer and display data on the LCD. the white 7 pin plug is probably used to transfer information to the printer and probably provide power to the LCD and backlighting. Maybe even screen contrast. I haven't even begun to trace circuits yet, I may be over my head doing that on this board.
Any help appreciated.

Here are some photos of the control board

Here are photos of the LCD board itself

Thanks for any help.

Sorry, but that really is an orphan part. :astonished:

There are two chips on the board, the larger EA212-00770A is clearly the graphic LCD driver but completely undocumented and unlikely to resemble in any way any chip with which people here are familiar.

The MB624496 which according to this article is found in another printer, the HPLJ4P, is essentially a OTP microcontroller, again completely undocumented in a practical sense.

Essentially 100% useless! :sunglasses:

Paul__B:
Sorry, but that really is an orphan part. :astonished:

There are two chips on the board, the larger EA212-00770A is clearly the graphic LCD driver but completely undocumented and unlikely to resemble in any way any chip with which people here are familiar.

The MB624496 which according to this article is found in another printer, the HPLJ4P, is essentially a OTP microcontroller, again completely undocumented in a practical sense.

Essentially 100% useless! :sunglasses:

OK, good to know. Many thanks. It was worth the try.

It's all about "proprietary" equipment, both software and hardware.

Without documentation, it is all essentially encrypted. :grinning: Re-use is not just not intended, it goes completely against the commercial ethic.

That's life! :roll_eyes:

Yeah, and that's really too bad. Because now something that could have been used will end up in the recycle bin, or worse the land fill.

It would be nice if someone could pop up and prove me wrong, but ... :roll_eyes:

The modul is quite useless without any documentation. The only this you can try is to attach it back to the printer and try to figure out how it is controlled.

First you need to identify the power rails.

  • GND
  • 12V?
  • 5V?
  • 3V?
  • some negative LCD driving voltage?

The remaining 3 to 4 pins should be used for communication.
Hook up a logic analyzer and try to identify

  • clock
  • data
  • chip select?
  • read/write?
  • data/register select?

Try to make any sense of what you see

  • figure out the command structure
  • figure out the supported commands
  • ...

When you are desperate enough or having fun figuring things out, give it a try.