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Mar 20, 2016

How to Reset a Comcast Cable Box

Disclaimer: Do the following procedure at your own risk. I'm not a Comcast insider. I'm just good at debugging.


Your cable box has lost signal without being able to recover. Comcast’s customer support has sent a reset signal, but the box is not responding to it.


What I believe has happened is the box has lost trust in Comcast. Now it refuses to accept any signal from the remote port including a reset signal.


The solution that has worked for me is to deactivate the box, and then to reactivate it.


1. Reset/deactivate the cable box:

  • Press and hold "0" on the remote control for about 5 seconds until the diagnostics menu comes up.
  • Quickly press "1", "3", "7", "9". This will reset/deactivate the box.

2. Wait until any visual activity stops. Reboot the cable box.

3. Verify the box appears as "not activated":

  • Press and hold "0" on the remote control for about 5 seconds until the diagnostics menu comes up.
  • Switch to the item that looks like "DTA status" and click on it.
  • You should see something like "Activated: No".

4. Call Comcast (or do it over an online chat - it's much faster) to ACTIVATE your box. You'll need the serial number of the box which is printed on a label on the bottom of the box.

Within a couple of minutes, TV signal should come in.

Mar 17, 2016

Systems of Linear Equations - Free for All

Some of my friends are familiar with the Windows Store app I wrote a couple of years ago that teaches kids how to solve systems of linear equations. The app generates problems with up to 5 unknowns, describes full step-by-step solutions, or shows just answers.

The news is that I've ditched the Windows Store, and I've made the app freely available as a web service. It is available for all smart devices from all geographical regions:

The app is designed for small form factor devices. So please try it from your phone.

This was made possible by the free web hosting at GitHub Pages.