In April and May the HPS Light on the back wall of my house ten feet above the ground and above the air conditioner and concrete patio next to the basement back door started showing signs of the bulb burning out.  The light would take extra-long to light up at night compared to all of the almost 5 years before ever since it was first installed by myself in July 2018 when at dusk the bulb would start lighting up automatically by the photocell switch located on the top of the fixture.  Day after day the light would take a little extra time to come on.  I realized that the bulb was burning out, so I started shopping for one.  I found one locally and got it and tried it out, but by then the bulb had burned completely out and the new bulb did not light up.  What next?  I really like this light, so I want to keep it. 

     This light fixture is a "Heath Zenith Model 5679 Dusk-To-Dawn Patio Light" and is no longer manufactured.  Bulbs are available and so are the other replacement parts.  The HPS light puts out a yellowish/orange color light and is very efficient.  The color of the light emitted doesn't attract insects in the summertime as do many other exterior lights, isn't too bright, and it lights up the entire backyard very well.  It uses a 70watt bulb and is at least as efficient as an equivalent LED light fixture.  The light fixture is in very good shape and needs repaired.

     Looking over the fixture "Installation Instructions" I found the "Ballast Assembly Replacement Instructions".  Of course, I am a trained and very capable Electrician (licensed Master Electrician) and have changed light fixture ballasts before.  This is something I do and have expertise in.  #1 the bulb was definitely burned out.  #2 the replacement bulb (70watt HPS type S62 bulb) did not light up when it was installed.  #3 the most likely cause is a defective ballast.  A replacement Ballast Assembly (ballast and ignitor) was purchased online widely available in the needed 120volt 70watt S62 type--capacitor not required.  One week later the package arrived, and the ballast assembly changed.  Complete details and pictures of the repair are available as a YouTube video at https://youtu.be/6XR0wAT80c0