Community Forums

Tboh · 02-15-2008, 07:01 AM

I have an Onan 7.5 in a Class A. There are lines rolling from bottom to top on the TV's when on Generator.

Anyone hear of this? Have a fix?

Thanks,

Tboh · 02-15-2008, 07:01 AM

I have an Onan 7.5 in a Class A. There are lines rolling from bottom to top on the TV's when on Generator.

Anyone hear of this? Have a fix?

Thanks,

bjbkkb · 02-15-2008, 07:40 AM

Do you have an Electric Monitoring System (EMS) that tells you voltage, frequency and current? That might give you an indication if the power isn't clean.

Kablewizard · 02-15-2008, 08:20 AM

The lines slowly scrolling up your screen are called HUM bars: that is AC voltage that gets into your system. That is caused by several things mostly a bad ground. Those of us in an RV with a generator have several more possibilities then others. If you don't notice it when hooked to park power that helps limit the cause. I would start with checking the ground on your generator and then look at your power system (Inverter) to be sure your ground has not gotten loose from vibrations of driving. It's just a matter of insuring all the screws are tight on the ground bars. Depending on your unit there could be several locations. Also insure the frame grounds are tight also. We had lines on 1 TV only, checking the power plug I found it was turned wrong and the problem went away. I don't understand how it affected AC but it did. I hope this helps.

Tboh · 02-15-2008, 12:12 PM

Thanks guys, I'll do some research on the numbers coming from the rig.

The inverter and from shore power show no hum bars. Only with the gen. It changes with the load on the gen too.

Hummm.

RedneckExpress · 02-17-2008, 09:31 PM

See if you can get an electrical shop to test your output voltage with an ocilliscope to check the sine-wave pattern of your 120. If its not a smooth 65hz wave, you're genny is creating unclean power which messes with electronics and electrical motors.

Bob (WA0MQE) · 02-18-2008, 03:45 AM

Most smaller generators, including the ones in RV's, do not have very clean power. This is because it's expensive to build a generator that will give you the same clean power as commercial power. The generators are a mixture between modified sine wave and pure sine wave. It's not unusual at all to have this problem in your a television set. This also depends on the filtering built into the television's own power supply. Some are better then others.

Tboh · 02-18-2008, 03:50 AM

All good info.

I also should have mentioned this is a new issue and the gen has only 600 or so hours on it.

I'm going to check those grounding points first, then seek out some expertise if thats not it...

Thanks

Gary RVRoamer · 02-18-2008, 04:25 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">If its not a smooth 65hz wave, </div></BLOCKQUOTE>

Should be 60 Hz, not 65.

NeilV · 02-18-2008, 06:50 AM

Try turning off the roof vents or other DC motors (those that have brushes) and see if that helps.

Tboh · 02-18-2008, 07:26 AM

The Onan 7.5 seems to be all solid state with no adjustments possible. Must be something 'environmental.

I did have the fans running this last trip... you may have something there.

Hummm, interesting.

Route 66 · 02-18-2008, 07:31 AM

The 7.5 QD has pure sine wave inverter built in and it has a high quality output.

Tboh · 02-18-2008, 07:47 AM

Thats what I'm reading. Neat gizmo for sure. Seems to be an all or none system so the ground or the back interference seems to the the likely culprit. I'll have to get under it and check arround.

Thanks,

george henry · 02-27-2008, 06:21 AM

Always let the gen run for about 3 minutes to warm up before putting any load on it . Also lots of folks forget to let the gen run a few minutes on it's own without any load before shutting it down.. I think your small problem was the power fans in your vents running at the same time your Tv was on when you were on gen.
Mine did the same with I when back to shave while my wife was driving on the gen with 3 tv going on the same time and yes I had the blender running to make margaritas yes it had lines all three tvs at the same time , but when I shut off the electric shaver and blender that I had plug in , it when away on all 3 tvs.
No big thing , I can live with that. just takes two minutes or three to shave and make drinks.