Replacing PC Parts

Computer Repair with Diagnostic Flowcharts

Starting Your Own Computer Business

The Laptop Repair Workbook

Questions? Comments?

Copyright 2011 by Morris Rosenthal

All Rights Reserved

Replacing a Modem

Copyright 2011 by Morris Rosenthal -All Rights Reserved contact info

Illustrated How to replace a modem (Internal 56K)

All of the other replacement illustrations on this site are shown with computers built in mid-tower cases, so just for variety, I've illustrated installing a 56K modem in an old style desktop case. The only difference is how the cover comes off and how the case sits, the ATX motherboard and modem are identical to those used in tower cases. As with pretty much all generic case designs, you remove the cover by removing the screws on the back are through the painted surface of the case cover.
Once the screws are removed from the desktop case (three in this instance, some use five), the whole cover lifts and slides out. If what remains looks familiar, it's the standard mini or mid-tower cases are essentially desktop cases stood on end. You can see the ports on the modem we are installing between the video and sound card ports on the back of the case.
Standard PC adapters are secured with a single screw (unless the case employs a locking bar system), so the first step to install our modem is to remove the screw. Note the brown capacitor near the top of the card, the exposed circuitry on internal modems can give you a nasty little jolt if you handle them improperly, even though the power cord has been disconnected. Doesn't do much good to know how to install a modem if you can't get the old one out without zapping yourself:-)
Our new 56K modem has the capacitors mounted vertically rather than horizontally, so you can see I'm not cheating and just putting the same modem back in:-) The most common reason for modem failure is lightning strikes, and modem often fails open. This means if you come home one day and your telephone is dead (no dial-tone), and all the phones in the house are hung-up, the next step is to disconnect the computer modem. If the phones in the house are fine after the line connection is disconnected, it's time to replace the modem.
When you install the modem, be careful not to touch the contact edge (the gold stripes) when handling the adapter, and hold it by the metal bracket the back corner of the card. Seat the modem in the PCI slot with even pressure on the top of the card. Once it settles into the slot, secure it with the screw, but don't tighten it until you confirm that the ports fully exposed through the back of the case (below). Also, make sure the "line" port on the modem is connected to a live phone jack in the house. The "phone" port on the modem is for attaching a regular telephone.

Don't replace anything without seeing the cable, DSL and 56Kbs modem troubleshooting flowchart!