GLCD Board not working

I have a k40 with upgraded cohesion 3D board, GLCD controller, stepper motor for z table.
I am just now able to work on upgrading my k40 with parts I bought from you a while back. I am having an issue with the GLCD not working. At first I thought it was the board (I dropped the first one I ordered) so I bought another and it is not working either. I am attaching pictures of my setup to see if you can help.

I put tape on the ribbon from 2


With external power supply for z table connected.

When powered on there is a red light in the middle and green lights with a couple flashing

machine:Board: _cohesion 3D

Does the screen get a backlight or dark?

Can you flip the cables around as shown here?

Did you mean to attach more pics or is it just the 4 at the top?

The screen does nothing. I’ve reversed the cables with no affect. I can attach other pictures if you’ll let me know what you’d like to see

Is there anything else I can try? I have tried both lcd boards with cables each way. Did turn GLCD adapter around as well. Still nothing. When I power the unit on there is a hum from the gantry but no response when I try to entries from to dark lcd board.

Have you tried to use both sets of cables, just to rule that out also?

Would you be able to take clear pictures of the front and back of the LaserBoard, GLCD Adapter, and a GLCD screen for me please?

I have tried both sets of cables. I will send pictures late Thursday the 9th.


I have used two sets of cables and both glcd boards. With same result. Nothing to the board.

Does the LCD backlight come on at all? If so, there’s a potentiometer on the left side of the GLCD that controls LCD contrast. Have you tried adjusting it? From your picture it appears to be in the minimum position.

That’s for contrast, not backlight. There should be a backlight. I don’t see any evidence of manufacturing problems from the board pics, and it’s very strange that the board operates (ie: produces the required 5 volts to operate itself, but not the GLCD), and that the issue persists across 2 screens. I’m thinking about it…

@CJEnterprisesLft can we see pics of the GLCD Adapter top and bottom also?

Right. If the backlight fires and the board is getting power, the contrast could be all the way down and that’s why there’s nothing on the display :slight_smile:

But he says there’s never a backlight. And that’s what stumps me.

I missed that. Yeah. this is a strange one.

I’ll try but there seems to be nothing. When I try to toggle x, y and z by guessing, counting how many times I press the knob, and then jog nothing happens.

Any suggestions? I sent an email earlier today as well

Hi Corey, we have received your messages, are currently working on figuring out a solution, and will be in touch shortly.

The new laser board arrived but still having same issue with the lcd board doing nothing. Here are pictures of how it is connected.

The first picture shows the adapter connected backwards.
The second picture shows the adapter connected correctly.

Then, if your sharpie on the ribbon cables is accurate, you have the ribbon cables switched with each other.

Okay thanks will try tomorrow