Converter hum (gets louder...)

[tsteve65]

We recently purchased a 88 Coleman Newport (1st camper) and when I plug it in to 110v the converter has a slight electrical hum, which I expected and seems to be normal from a lot of reading/searching on here.  If I leave it plugged in for a couple of hours the hum becomes a lot louder (loud enough that it would be very obnoxious at night).  It still seems to be an "electrical" hum, not a fan.

The camper does not have a battery, not sure if it came with one.  I have seen on here where the converter will hum if no battery (load) connected, but I don't think this is a "charging" converter???

Is the loud hum also normal after being plugged in (heating up???) for awhile?

Thanks.  Todd.

[AustinBoston]

Our converter (which is several years newer than yours, so may be different) has a variable-speed fan, based on (I assume) the internal temperature of the converter.  If it's a warm day, or if we have several lights on simultaneously, the fan will run faster.  Some time after all the lights are off, it will turn down.  If it's quite cool, the fan may not run at all (or runs so slow we can't hear it).  Even on high, it is not offensive.

There may be something (leaf, scrap of paper, etc.) in the fan, and it gets louder and annoying when the fan is running higher.

If it is clearly not a fan issue, it may be a loose mounting somewhere.  There is no reason that solid-state electronics should hum, with just a few exceptions.  Things with magnetic fields (such as transformers or chokes) may want to vibrate under certain circumstances.  Usually, if they are screwed/bolted/glued securely, they don't, but sometimes that just means the panel they are attached to vibrates instead.  

Start by making sure the converter is mounted securely.  If that doesn't help, try removing it, and seeing if there is something causing the fan to make noise.

Austin

[tsteve65]

Was able to look into the converter buzz a little deeper last night.  Pulled out the panel the converter is mounted to...  It doesn't seem to have a fan and the buzz seems to be internal.
The converter is a B-W Manufacturers Inc. Model 6406 (Series 6400A). After a Google search it looks like this may have been a problem (buzzing) with others of this brand/model. Looks like B-W no longer exists.
So, next question is where to search for replacements (probably little chance of finding one with the same dimensions), this model does have a 110v outlet on the panel itself plus fuse, converter/off/battery switch and main breaker/on/off switch. There is only one other 110v outlet in the camper plus 2 12v lights.  Also has wires run for the heater but no heater installed.

[fritz_monroe]

This  is what they put in many of the newer popups.  This has a built in charger also.  These don't have an outlet on the front, but putting in a couple outlets a piece of cake.