Electric Pulsation
 

Hi All,

I have two roundie color tvs that seem to be sensitive to the pulsations in the electric current. I notice it in the incadescent light bulbs in my house also, but not in my flat panel sets. Am I correct in assuming that the electric service is the cause, or is there something I should check on the tvs? One is a 1964 Magnavox comb, and the other is a 1967 Zenith.

Thank you for any advice you can give me.

Frank

normal for sets to react to sudden changes in voltage due to loads like AC coming on, I have a printer that causes it, you can see the pic effected about every 15 seconds when the printer is on and acting up.

Like I said, both sets do it, so I knew it wasn't something peculiar to one set or the other.

AC units kicking on are the worst offenders, they can make the picture fall out of sync if bad enough.

You might also notice it when the icebox kicks on. A washing machine (older one with an AC motor and transmission) could also cause it while agitating. Older homes are the worst offenders. A neighbor I had years ago had a home that ran on a total of 4 breakers... any item that used significant current would be noticed throughout the entire house.

Very noticeable in older homes with just a couple of fuses and appliances going: typical washing machine pulsation making the TV picture shrink slightly in time with the load on the motor. I knew a family in Beaumont TX where in the summertime the lady would start ironing, then get too warm, and switch on the attic fan. The starting load of the fan motor would blow the fuse. They had to teach her to unplug the iron, turn on the fan, then plug the iron back in. Living on the edge!

I had a increasingly noticeable problem like you're describing about 5 years ago. If the central air or heat came on, I'd lose width on my sets. The washing machine caused problems as well.

The power transformer on the pole outside only services my house. That tranny was pretty old... even starting to show a lot of surface rust. I called Entergy, and they came out to have a look. At first glance, the guy said it could be the problem. He told me he'd come out again with a device to put it under a heavy load and determine if the tranny needed changing. A couple of weeks later, I went to sea and was gone for two months. When I returned home, there was a brand-new tranny on the pole, and the voltage drop issues I had been experiencing completely went away. No problems since then.

The house is only about 15 years old, but the electrical service outside is ancient. Here on Long Island, LIPA is a joke.

You mentioned a computer printer. Most laser printers have a heat fuser assembly that can draw 1000 watts plus or minus. Keep that in mind. Newer flat TV's have regulated Switching power supplies that do well regulation wise so you won't see line volt prob's.

Wow... that's a lot of juice for a printer!

Keep in mind the older sets used a straight foward power supply with no form of voltage regulation. The newer sets all have voltage regulators with for the most part can handle a wide swing on the input voltage.

I know this may sound strange, but where I live, there's no above ground power poles or anything like that, it's all underground.

Where would they even put the transformers for situations like this?

In subdivisions with underground wiring, there will often be metal transformer boxes above ground, sometimes in between houses, to serve several houses. I'm not aware of underground transformers but there may be some but wonder about such an installation flooding.

You ain't kidding!
I was from Mastic myself....

Ha-ha... some people here might be too young to know what an attic fan is! :D