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Akronguy · 05-23-2014, 01:32 PM

Just bought the 93 Excella a couple of weeks ago and in the process of fixing it up.

Loud humming is coming from the converter. It seems to have become loder in the past week. WHen we turn on the radio it is 90% humming noise. Also, when I unplug from line in garage, the battery is not supplying any voltage for lights etc. (see pic). The batteries are less than 2 years old.

1) Is there a reset switch somewhere that would charge the battery?
I ask because I had a MH where a tiny switch had to be pressed if it
popped out to charge the battery when connected to 110.

2) Is the converter original? (See pic) If replacement is warranted what converter/charger should I replace it with? Preferably I would want one where the lines match up with the new unit.

**DKB_SATX** · 05-23-2014, 02:02 PM

Generally the converter humming is a sign that the converter is energized and working (and old), though it's possible that there's some discontinuity between the converter and the batteries. The converter shouldn't be a loud hum, though.

When the converter is plugged in do the 12v lights and devices work in the trailer?

If memory serves, some Excellas had a switch to turn off the converter, but I don't think Airstream had started putting in the battery-disconnect switch by then (I may be wrong about the disconnect switch.) Newer trailers do have a store/use switch that disconnects the battery via a solenoid, and some previous owner may have installed a manual disconnect in yours.

You can have the batteries checked out by someone with a tester, or you can try charging them from a known-good source and see if they recover. If something is wrong with the converter (and they don't hum loudly or interfere with the radio when everything is working properly) it may have been over-charging the batteries, or it may be as simple as a broken connection or bad fuse between the converter and the batteries.

AWCHIEF · 05-23-2014, 02:23 PM

I consider mine a very good white noise machine. As long as it is humming it is working.

Akronguy · 05-23-2014, 03:35 PM

Well, I went and checked the batteries which are not 2 years old as had been stated. They are Interstate batteries (srm-24) and were bought in 2000. Both were bone dry.
Guess I will start there, but would that cause the converter to hum loudly and the radio to also drown out music by the hum?

overlander63 · 05-23-2014, 05:09 PM

Open batteries will no longer filter the current, so it is very possible if you replace the batteries, the hum will stop. If not, you will have two choices. First, replace the converter with a more modern unit with 2 or three stage charging. Second, try supplying a songbook so it won't have to hum any more.

Okay, that was bad...

**DKB_SATX** · 05-23-2014, 05:10 PM

Quote:

Originally Posted by Akronguy

Well, I went and checked the batteries which are not 2 years old as had been stated. They are Interstate batteries (srm-24) and were bought in 2000. Both were bone dry.
Guess I will start there, but would that cause the converter to hum loudly and the radio to also drown out music by the hum?

Trying to charge dry batteries old enough to get their learner's permit didn't help it any.

It may quiet down with good batteries. In the worst case, a better, modern 3-stage converter will likely eliminate the radio noise and isn't too expensive if this one turns out to be damaged.