Community Forums

coeranch · 09-24-2018, 02:21 PM

Afternoon!

I tried to search and review old posts, but couldn't find my specific issue. I have 16K miles on my 2016 Palazzo 33.2, and this problem just recently cropped up - that I noticed, anyway. When I'm stopped at a rest area for lunch, and therefore just running on battery power, I hear a high-pitched hum/whine from my MW; and if I turn on the MW light, it flickers (on both high and low). Yet while on shore power it doesn't do that - works as advertised. I haven't tried the genny yet to see how it works then... Everything seems to work fine; so it appears I've developed a short or something somewhere in the inverter path to the MW. So - has anybody else experienced this? Thought I'd ask the community before calling the tech staff at Thor. Appreciate any help!

RVL14all · 09-24-2018, 02:28 PM

Hi,
My 33.2 does that same thing and I am worried that the microwave will get damaged. So, I start the generator anytime I am at a rest stop (etc) before using the microwave (unless I have shore power). It is good to run the generator often anyway. I no longer use the microwave on inverter. Everything else works fine on the inverter.

Spk64 · 09-24-2018, 02:31 PM

If your inverter is a Modified Sine type you may have some issues with electronics.

msturtz · 09-24-2018, 03:32 PM

Microwave ovens don’t like MSW power. The magnetron is trying to generate and emit RF energy in the microwave bands. She square wave input power creates problems for the magnetron and related circuitry. It will shorten the life of the microwave. My inverter was replaced with a pure sine inverter.

TonyMac · 09-24-2018, 03:35 PM

Maybe its humming because it doesn't know the words....

Palazzoteam · 09-24-2018, 09:56 PM

although the microwave can be ran with inverter(batteries close to full)..... We noticed it to humming(while on inverter).... but never with gen or Shore power. So we decided only to run microwave with those 2 options only. Just afraid of what it may do when it hums!! I've heard the same thing with WAVE inverters(if ours ever dies... we are going with PURE) 33.3 2013

iluvuk · 09-24-2018, 11:10 PM

Quote:

Originally Posted by coeranch

Afternoon!

I tried to search and review old posts, but couldn't find my specific issue. I have 16K miles on my 2016 Palazzo 33.2, and this problem just recently cropped up - that I noticed, anyway. When I'm stopped at a rest area for lunch, and therefore just running on battery power, I hear a high-pitched hum/whine from my MW; and if I turn on the MW light, it flickers (on both high and low). Yet while on shore power it doesn't do that - works as advertised. I haven't tried the genny yet to see how it works then... Everything seems to work fine; so it appears I've developed a short or something somewhere in the inverter path to the MW. So - has anybody else experienced this? Thought I'd ask the community before calling the tech staff at Thor. Appreciate any help!

I haven't noted this problem on mine. I use mine on inverter all the time.

vsheetz · 09-25-2018, 12:10 AM

MSW or PSW? If MSW not unexpected to sound differently.

coeranch · 09-25-2018, 07:28 AM

Sorry, I should have been more specific: I don't use the MW when not on shore power; it hums while just sitting there! Once I plug in shore power, it stops humming and the lights no longer flicker. So yes, I assume it's an electrical issue; either in the MW itself, or the inverter pathway. My next step is to call Thor.

But yes, TonyMac, I can at least start by providing the words to my MW!

firestopper · 09-25-2018, 08:40 AM

Take a multimeter and verify the voltage at the receptacle , perhaps the inverter is not putting out the recommended voltage. To me,it sounds like the MW isn't getting the required power from the inverter. Appliances or electric motors won't last long under these conditions.

msturtz · 09-25-2018, 09:23 AM

The problem is square wave vs sine wave. Thor installs a square wave (Modified Sine Wave or MSW) inverter. The square wave inverter does not produce the correct voltage or waveform that microwaves and motors expect. They also produce 1st, 2nd and additional harmonic distortions that also create other problems. Oddly enough switching power supplies can handle square wave power because they operate differently. In addition, most things that simply rectify the power to DC also usually work fine.

coeranch · 09-26-2018, 07:01 AM

I'll definitely check the voltage... What's bothering me is that this issue just started on our last trip - the fourth trip this summer. So something's changed, and not for the better.

Thanks for all your inputs!

NeeNee33.4 · 02-09-2019, 02:17 PM

Don’t use your microwave on inverter, turn on your generator

HaRVey 74.5 · 02-10-2019, 10:46 AM

I just went through a similar discovery with our new 2018 Palazzo 33.2 the first time dry camping.
My wife's heating pad controls got hot and burnt through the cover and her juicer wouldn't work.
Checked voltages and called Magnum thinking something was wrong with the inverter only to have Magnum advise that we had a Modified Sign Wave inverter (ME2012) which should NEVER be used with heating pads (had several fires reported) and are NOT recommended for anything with a motor (can you say, residential fridge..), microwaves, any heating device with digital controls (coffee makers, etc.) because they will run inneficiently and fail prematurely.
I ordered and installed a Magnum Pure Sign Wave replacement inverter (MS2812, upsized too), now everything works and we won't burn to the ground.
My question to Thor, was "why did they cheep out ($500 retail price difference, $100-200 wholesale) for a device which is not recommended by the manufacturer (Magnum Energy) and is in fact dangerous (no warnings in any literature or even 1 cent stickers). Thor is refunding me their cost of the ME2012 inverter ($500, which is better than I expected!)