Found a fix for "No Alde heat" when all fuses are good

Be careful soldering thermal cutouts as the heat of soldering can cause them to melt open.  91C is pretty hot for a circuit board and would only result due to a major fault that might otherwise cause a fire.  If you suspect you have had this part fail, be sure to inspect the circuit board for charging or damage.  Replace only with an identical part.  91C (195F) is at least twice the temperature a circuit board should ever see under normal conditions.

Verna said:

@ChanW, I was working with Marvin and we agreed it would be quicker for me to replace rather than troubleshoot any longer. We never discussed replacing a soldered fuse, and I do carry an inexpensive soldering iron.  After all, I was without heat, and even AZ gets cool at night. Thank goodness I always make room for a compression sack with my sleeping bag inside

But anyway, no, the circuit board was not sent back to Alde. After working with different circuit boards for most of my career, I’m always curious about burn marks showing what failed.  The phone company never allowed us to replace anything soldered on a circuit board, preferring to allow those companies with a static free environment to refurbish the circuit boards.  (I cringed at how many of my co-workers treated the circuit boards without regard to possible damage by static electricity.)

I'm guessing you carry a multimeter too, so if you still have the circuit board, it would be interesting to know if F2 is the culprit.

This is our 4th year with our 2015 (bought in 2014) T@B Max Q. We left Dec 31 from the KC area for 7 weeks on the road. The 1st night out we fired up the Alde for hot water and everything worked fine until the next morning when we noticed the water was only lukewarm and the Alde wouldn't come on at all. I checked all the obvious fuses as well as the 2 on the Alde itself, they were all fine(its never something easy).  I googled troubleshooting and originally came up with this post from a guy in the UK   https://www.motorhomefun.co.uk/forum/threads/alde-3010-blank-control-panel-solution-fix.154521/   Sure enough, when I tested the thermal fuse it tested "open" and I confirmed this by bypassing the fuse with some alligator clips (diagnostic only) and the Alde fired right up (you have some limited access to this fuse without removing the PCB).  Grrrrrr, 1st night out, seriously?????  Luckily we always carry our sleeping bags and can heat water with propane or an electric tea-kettle.   We purchased a small electric personal heater that helped take the "chill out" for the rest of the trip when we had electricity.
When we got home I went ahead and ordered the fuse, pulled the PCB and found a place in the KC area called Phone Medic that for $30 had the fuse replaced for me in less than 2 hrs. Plan B was to attempt the solder repair myself but without any of the tools or experience this seemed like money well spent. Everything is working fine again but a little disconcerting that this appears to be happening to several of us. Thanks for the great pictures and write up.  FYI,  I didn't notice any burn marks on the PCB.                                                                                       

Yes, that was initially how I found out about problems with a thermal fuse in the Alde and later found this post about the same thing. Point being, we’re all talking about the same problem with the same fuse.

Well our Alde up and quit today.  Had been using it all winter keeping the camper around 55 degrees. I shut it off 2 weeks ago as we were going on vacation.  Turned it on the morning, went out this afternoon, and camper was cold.  Checked the fuses, and all was good.  Remembered this thread, and jumped the thermal fuse on the control board, and it fired right up.

Apparently the newer Alde has a resettable thermal fuse.  Has anyone (ChanW?) put one on their Alde?    I'm hoping to do that.  If not, I'll be carrying a short wire with alligator clips to jump it in an emergency.  Not going to worry about frying the rest of the control board if it's a cold camp.

I never should have responded to that Alde reliability thread.

ChanW said:

Yes, ours is one of the first that Little Guy installed the Alde in. Our driver-side wall even has the hole cut in it for the old style furnace exhaust, right next to the Alde exhaust.

Ours has that too. It is a unique little "quirk". At first, I thought it was part of the Alde vent system but then I looked under the bench and saw it went nowhere and just laughed. It was probably installed in all the walls by default but when they switched to Alde, they already had the walls made. 

Here’s a very interesting article about the ethics of thermal fuses (they contribute to the problem of repairable products being sent to landfills). At the end of the article there’s a suggestion to crimp the new thermal fuse in place instead of soldering.

http://www.evonet.com/evonet/index.asp?Page=34&ID=34

So I chickened out on putting in a replaceable fuse, and ordered 10 thermal fuses from DigiKey just like the originals.

I happen to have a computer genius, inventor, motor head, Jack of all trades friend next door, with albeit rusty soldering skills.  We only ruined the first one because we spaced on the heat sink alligator clips for the first solder point. 

I now have a lifetime supply of fuses, and knowledge of how to repair.  I will be making a short 16 guage wire with alligator clips to jump this fuse if it goes bad on a trip, as long as there's no sign of something malfunctioning/burning.  Also taped a Torx 10 to the Alde so I can get to the circuit board.

Hopefully someone else will do the plug in fix and post, if this fails again I'd be tempted.

Photomom said:

Here’s a very interesting article about the ethics of thermal fuses (they contribute to the problem of repairable products being sent to landfills). At the end of the article there’s a suggestion to crimp the new thermal fuse in place instead of soldering.

http://www.evonet.com/evonet/index.asp?Page=34&ID=34

@Photomom ironically, that link is "faulty," lol. I'd like to read that article but couldn't find it on their site. Do you have a good link? TIA

Thanks @Photomom that works!