Hi,

I have an old lk204-25 rev 2.0 witch seems to be dead i think.
It is serial model.

Display is full of weird characters when powering it up and it dosen't show any kind of boot logo. Witch it use the do when it was new.

Is this totally dead, or are there any possibility to fix it somehow. ?
I maded reset but i didn´t notice any difference.

Any ideas what to try, please.

thank you
Poikkis

Do a manual override and see if that allows you to communicate with the display.

Nope, didn´t help. Can´t communicate with the unit.

Is it possible to remove the back pcb and replace that
some universal serial backpack unit. ?

- like how many 44780 parallel lcd controllers are builded.
(eg. Hitatchi 44780 display with serial backpack unit)

Thank you.
Poikkis

Hi Poikkis,

Sorry to hear the display did not respond to the manual override procedure. What are you using to communicate to the display?

Make sure you are communicating at 19200 baud with 8 bits data, no parity bit, one stop bit, and no flow control. If you are using a micro controller you may need to put the unit into TTL mode.

If you'd like to attempt a hardware repair, the X-Board would be your backpack unit; the S-Series will provide a serial interface.

The fix won't be easy and will require some soldering skill. You'll have to remove the back communication PCB from the screen and clear all 14 mounting holes. You'll then solder the proper header to the X-Board and solder that to your screen. Finally, you'll program the board to work with a 20x4 VFD. All assuming the screen is still in good working order of course.

If you have any further questions regarding your VK204-25 or the X-Board, please don't hesitate to post.

Thanks,
~Troy