LCD Screen replacement on KDM20g Keypads - MultiCam USA CNC cutting machines

LCD Screen replacement on KDM20g Keypads - MultiCam USA CNC cutting machines

KDM20G Keypad LCD Screen Replacement — Step-by-Step Repair Guide

MultiCam CNC Tech Hub  |  KDM20G Keypad Repairs  |  By George  |  11 July2026


KDM20G keypad LCD screen replacement — complete guide.

The LCD screen on a KDM20G handheld keypad displays all critical machine information — axis position, machine status, menu navigation and error codes. When it fails or is physically damaged, the keypad becomes unusable. The good news is that screen replacement is a straightforward procedure if you follow the correct sequence and take care with the ribbon cable connection — the one step that catches most people out.

This guide covers the complete LCD screen replacement process for KDM20G handheld keypads used on MultiCam USA CNC routers, plasma, knife, waterjet and laser cutting machines.

What you'll need: Replacement KDM20G LCD screen (with or without Rev2 holder), small Phillips screwdriver, fine-tipped tool or fingernail for ribbon cable latch, double-sided tape approximately 1.5mm thick (if reusing the HDPE mounting layer), soft cloth or mousepad for working surface, marker or scribe for alignment marking.

Step 1 — Disassemble the Keypad Housing

Remove the six screws from the keypad housing.

NOTE — Screw lengths: Some KDM20G keypad models use two shorter screws at the top of the housing. Take note of which screws came from which positions before removing them — they must go back in the same locations on reassembly.

Separate the internal assembly from the outer housing frame. In most cases no soldering points need to be disturbed — the assembly lifts free cleanly. Place the internal assembly face-down on a soft surface such as a folded cloth or mousepad to protect the overlay and prevent it sliding around while you work.

TIP: While you have the housing open, take the opportunity to blow out any dust, swarf or debris from inside with compressed air. This is the easiest time to do it and makes a significant difference to long-term reliability.

Keypad housing disassembled — internal assembly separated from outer frame and placed on a soft surface.

Step 2 — Remove the Graphics Card and LCD Assembly

Unscrew the four screws holding the graphics card (KDM20G_CNT) and LCD assembly to the PCB mounting posts. Lift the assembly clear and place it on a soft surface. Handle this assembly with care — it is the most valuable and sensitive component in the keypad.

CRITICAL — Mark the LCD screen position before proceeding: Before separating the LCD screen from the HDPE mounting layer, mark the exact position and orientation of the screen on the layer. The screen must be replaced in precisely the same location for correct alignment through the overlay window. Use a marker, scribe line or tape reference. Mark the screen side (S) and orientation (up arrow) so there is no ambiguity when fitting the new screen.

Graphics card and LCD assembly removed from PCB. Mark the LCD position on the HDPE layer before proceeding.

Step 3 — Release the Ribbon Cable

Before you can separate the LCD screen from the graphics card, the ribbon cable must be released from the ZIF (zero insertion force) connector port on the card.

Locate the small black locking strip at the ribbon cable connector port. Using a fine-tipped screwdriver, small spatula or fingernail, carefully lever the black strip upward — it will click up and release, exposing the ribbon cable for removal. Do not pull the ribbon cable before the latch is fully open or you risk tearing the cable.


Locating the black ribbon cable locking strip on the graphics card connector port.


Black locking strip levered up — ribbon cable now free to be removed from the port.

NOTE: The black locking strip pivots up from one edge — it does not pull out. Apply gentle upward lever pressure only. Once it clicks up the ribbon cable slides out freely with no force required.

Step 4 — Remove the Old LCD Screen and Fit the New One

With the ribbon cable released, separate the old LCD screen from the HDPE mounting layer. Insert a thin blade or scraper into the double-sided tape bond at the edge of the screen and work it free carefully.

Clean the HDPE layer surface where the screen was mounted. Apply a new strip of double-sided tape — match the thickness of the original as closely as possible. The recommended thickness is approximately 1.5mm. Tape that is too thin will leave a gap between the screen and the foam buffer on the PCB; tape that is too thick will push the screen too far proud of the surface and cause assembly issues.

CRITICAL — Screen handling: Keep the protective plastic film on the new LCD screen until the very last moment before final assembly. Do not press directly on the screen surface with fingers — finger pressure on an LCD panel can cause permanent damage. When pressing the screen onto the tape, invert the assembly onto your mousepad and apply light, even pressure to the back of the HDPE layer using the palm of your hand or a flat object such as a book.

Align the new screen to your reference marks from Step 2 and press down firmly and evenly onto the double-sided tape.

Old screen separated from HDPE layer — clean surface and apply new double-sided tape to the marked position.

New LCD screen aligned to reference marks and pressed onto the new tape — protective film still in place.

Step 5 — Engage the Ribbon Cable

This is the most critical step of the repair. Take your time — an incorrectly seated ribbon cable will result in no display or a corrupted display after reassembly.

Before attempting to insert the ribbon cable, orient the graphics card so the connector port is close to the ribbon cable end. Do not stretch the ribbon cable to reach the port — bring the card to the cable.

Confirm the black locking strip is in the fully open (up) position. Orient the ribbon cable so the printed side faces the correct direction — the cable is exactly the width of the port and the port has guide walls on both sides to assist location.

NOTE — Depth of insertion: The ribbon cable must slide all the way into the slot behind the brass contact pins on the card. There is a tiny gap/slot just above the pins — the cable must positively locate into this slot, not just rest against the pins. The white marker arrows on the ribbon cable are a useful reference — when correctly inserted, some of the arrows will be hidden inside the connector.

Ribbon cable oriented and being guided into the graphics card ZIF connector port — note the cable width matches the port exactly.


Ribbon cable correctly seated — white marker arrows partially hidden, confirming full depth insertion.

Once the ribbon cable is fully seated, press the black locking strip firmly back down. It must click closed positively and feel completely solid — no movement or looseness. If it will not click closed or feels loose, the ribbon cable is not correctly positioned. Open the latch, remove the cable completely, and repeat the insertion.

CRITICAL: A locking strip that will not click closed or feels loose after closing means the ribbon cable is not correctly located. Do not proceed with reassembly — a loose connection will cause no display or intermittent display issues. Remove and re-seat the cable until the latch closes with a positive click and zero movement.

Black locking strip closed and confirmed solid — ribbon cable correctly locked in position.

Step 6 — Reassembly

Remove the protective plastic film from the new LCD screen immediately before fitting the graphics card assembly back onto the PCB.

  • Carefully align the graphics card connector port onto the corresponding port on the PCB (the board with the button contacts). Ensure the card is flat and correctly located before tightening any screws.
  • Refit and tighten the four mounting screws evenly — do not overtighten, which can crack the mounting posts.
  • Reassemble the housing, ensuring the correct screws are returned to their original positions (short screws at the top if applicable).
  • Power up the machine and confirm full display function before returning the keypad to service.
TIP: If the display shows corrupted characters, partial lines or no display after reassembly, the most likely cause is the ribbon cable connection. Power down, open the housing, check the locking strip is fully closed and the cable is fully seated, and retry.

Final Notes

The ribbon cable engagement step is what separates a successful LCD replacement from an unsuccessful one. Everything else in this repair is straightforward — but the ZIF connector requires patience and confidence. If the latch clicks closed solidly, you have it right. If it does not, you do not — and it is always worth taking the extra time to get it correct rather than reassembling and finding you have a dead display.

If you are replacing the screen as part of a full keypad refurbishment, this is also the ideal time to fit the Rev2 LCD screen holder — which prevents the post fracture that affects the original holder design.

Need parts or support?

Replacement LCD screens, Rev2 LCD screen holders, overlays, button layer assemblies and all other KDM20G keypad components are available in our parts store.

If you run into difficulty with the ribbon cable connection or any other part of this repair, our remote technical support service is available worldwide — typically within 24 hours.

 

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