ATT CL4940 Motherboard Replacement

Introduction

Use this guide to replace a faulty or broken motherboard in your ATT CL4940 telephone.

The motherboard is the main circuit board which provides all connectivity between the hardware components of the device. A faulty motherboard can cause your device to run slow, and in some cases not work at all. Some reasons for motherboard failure include overheating, dust, power surges, and old age.

Before using this guide, make sure to check out the page on soldering and desoldering as this will be an important skill in step 5.

Be sure to unplug your device before starting as to avoid any electrical related injuries and/or damages.

What you need

Step 1 Motherboard

ATT CL4940 Motherboard Replacement, Motherboard: step 1, image 1 of 2

ATT CL4940 Motherboard Replacement, Motherboard: step 1, image 2 of 2

Disconnect the phone line and power cord from the back cover of the device.
Disconnect the phone cable from the side of the device.

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Step 2

Turn the device over on its front so the back cover is facing you.
Use a bit driver to remove all five 4mm X 10mm Phillips head screws from the back cover.

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Step 3

ATT CL4940 Motherboard Replacement: step 3, image 3 of 3

Using a metal spudger, start at the bottom of the device to separate the top cover from the back cover.
Work the spudger between the top and back covers of the device starting downwards, then to each side, and finally upwards.
There are brackets every few inches along the edge of the device which may be difficult to pull apart.
The top and back cover will separate and the internals will be accessible.