<p>So, the answer in the other referenced post was correct, the slots were turned opposite how they should have been. AND YES: you can create a &quot;crossover&quot; ribbon cable and everything works great, so physically turning the slots is not necessary.</p>

CC BY-SA 4.0
2020-10-28T19:48:08.937Z
2020-10-28T19:48:08.937Z
Bill in Kansas City
<p>Main board: MKS GEN L V1.4</p>
<p>The SD card reader on the original controller LCD (from four years ago, or so) went out, so I replaced it with a touch screen. I found, however, that I don't like the touchscreen interface as much as the LCD home screen, so I ordered what I thought was an identical LCD controller. They certainly look the same.</p>
<p>The original controller is plugged in now and working. It should just be a matter of the EXP1 and EXP2 cables between new and old, but when I plug it in and fire up the printer, the beeper starts a constant, weak beeping, the screen sort of flashes on/off, on/off... Is there something I'm missing? Some fundamental difference between the old LCDs and the new? Is there firmware I'm missing?</p>
<p>EDIT: <a href="https://3dprinting.stackexchange.com/questions/8091/lcd-full-graphic-smart-controller-no-character-display-and-screen-blinking">I saw this post that talks about turning the slots</a>, but they don't move and I'm afraid of applying too much pressure. How hard should it be? Can I accomplish the same thing by reversing the connector on one end of the ribbon cable?</p>

<reprap>
New RepRap Discount Smart Controller blinks and beeps, but doesn't display
Bill in Kansas City
# New RepRap Discount Smart Controller blinks and beeps, but doesn't display

(Asked by: username_0 on 2020-10-28)

Main board: MKS GEN L V1.4

The SD card reader on the original controller LCD (from four years ago, or so) went out, so I replaced it with a touch screen. I found, however, that I don't like the touchscreen interface as much as the LCD home screen, so I ordered what I thought was an identical LCD controller. They certainly look the same.

The original controller is plugged in now and working. It should just be a matter of the EXP1 and EXP2 cables between new and old, but when I plug it in and fire up the printer, the beeper starts a constant, weak beeping, the screen sort of flashes on/off, on/off... Is there something I'm missing? Some fundamental difference between the old LCDs and the new? Is there firmware I'm missing?

EDIT: [I saw this post that talks about turning the slots](https://3dprinting.stackexchange.com/questions/8091/lcd-full-graphic-smart-controller-no-character-display-and-screen-blinking), but they don't move and I'm afraid of applying too much pressure. How hard should it be? Can I accomplish the same thing by reversing the connector on one end of the ribbon cable?

**Tags:** reprap

---

## 1 answers

### Answer by username_0 on 2020-10-28. Score: 0

So, the answer in the other referenced post was correct, the slots were turned opposite how they should have been. AND YES: you can create a "crossover" ribbon cable and everything works great, so physically turning the slots is not necessary.


---

