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

ChanW

I went to warm up the Tab one morning last week, so we could have a little winter coffee-and-dominoes in the Tab, and found the Alde unresponsive. I figured it was the standard 'check the 2 fuses inside the Alde', but found them to be ok. Dang!

Electric was fine, battery was fine, propane was fine.

The Fleetwood Owners Club forum in the UK happened to mention F2, a 'safety fuse' according to the Alde service manual. It sits near the 2 'secret' fuses inside the Alde (F1 and F3), right beneath the 10pin connector for the control panel, so it was easy to test it for continuity without taking things apart. The device tested 'open'.

So I dug in. This 'thermistor' is called a 'thermal cutoff' or 'thermal fuse' here in the States, and it turns out it's not a multi-use device, contrary to the Fleetwood forum info. It doesn't reset.

I pulled the mainboard (the Alde service manual shows it to be a pretty simple process), and was able to desolder the 'fuse' from the board and then read the part number, DF91S. A check on the Digi-Key website found it available for $1.19 ea!

Specifications and cautions for handling and installing it can be found online, with helpful details like 'don't bend the leads too close to the body of the device', and 'be sure to use a heatsink when soldering'. Things I wouldn't have considered. thank goodness!
Got the new one put back in tonight, and the Alde came back to life!

Looks like dominoes and coffee in the morning!

I've attached the Alde service manual pdf.

The mainboard can be exposed by removing the 3 screws holding the plastic cover (after first removing the snap-on cover). I've reconnected all the connectors in this photo, to test the repair.


The Alde service manual describes unplugging all the connections, but be sure to make notes regarding colors of wires. I found them to differ from the documentation and the board markings.
The three black wires on the lower right of the board are not mentioned. I think they're connections for a relay. They're tough to reach with large hands, but lifting the board out a bit first will help.


The thermal cutoff is the little silver tubular thing right there below the 10pin connector:


Hope this helps someone. It was fairly easy for me, and I'm pretty out-of-practice when it comes to soldering.

Ramrod

Thank you!

gulfarea

A trick I would use would be to cut the old fuse out right close to the fuse leaving the old ends, then solder the new fuse ends to the old ones giving you more room to connect a heat sink while soldering. Then bend the extra wire to where it is not hitting anything. Thanks so much for bringing the answer to your problem to us. Another thing that might work would be to install an in line fuse holder with long wires to a more convenient place if it keeps going bad. Art

Nomad

Interesting - Haven't seen this mentioned before - Thanks

ChanW

Yes, leaving those leads in the board would have helped a lot! But it did give me the opportunity to try my luck again with the solder wick that's been in my toolbox for 20 years now. It worked pretty well. The old solder-sucker didn't work as well as it used to. B-)

I considered the fuse holder idea, but I couldn't think of one that will allow airflow around the cutoff.

I'll try looking around a bit for 'the next time'. Those leads are nice and long, so would be easy to solder onto.

gulfarea said:

A trick I would use would be to cut the old fuse out right close to the fuse leaving the old ends, then solder the new fuse ends to the old ones giving you more room to connect a heat sink while soldering. Then bend the extra wire to where it is not hitting anything. Thanks so much for bringing the answer to your problem to us. Another thing that might work would be to install an in line fuse holder with long wires to a more convenient place if it keeps going bad. Art

wizard1880

Hmm, that is unusual that those fuses would blow.  They're probably non replaceable for a reason, kind of like a last resort on the board when something really goes wrong.

If it doesn't blow again for another year, you're probably OK, and it was just a fluke somewhere in the system hopefully.  But if it goes again in short order, it's likely some other component like the blower fan, igniter, element relay(s), gas valve solenoid etc. is on the verge of failure, and it would need to be serviced by a trained Alde technician to identify and replace the faulty component.

You and I know how to solder, but we shouldn't expect everyone to, or be worried about carrying a soldering iron whenever you camp

ChanW

Yeah, good point. 

I tried contacting Alde to get some feedback on it, but got no response.

I'll be keeping a good eye on it for a while when it's all back together.

wizard1880 said:

Hmm, that is unusual that those fuses would blow.  They're probably non replaceable for a reason, kind of like a last resort on the board when something really goes wrong.

If it doesn't blow again for another year, you're probably OK, and it was just a fluke somewhere in the system hopefully.  But if it goes again in short order, it's likely some other component like the blower fan, igniter, element relay(s), gas valve solenoid etc. is on the verge of failure, and it would need to be serviced by a trained Alde technician to identify and replace the faulty component.

You and I know how to solder, but we shouldn't expect everyone to, or be worried about carrying a soldering iron whenever you camp

wizard1880

Coolness.

And hey, if they get enough feedback, perhaps future models will have replaceable fuses!

It would sure help if they reply though.  You're not the first person to find their support team unresponsive though, sadly.

Photomom

Excellent. I took a high reliability soldering course many, many years ago, but I'd probably have clipped the leads and soldered the new one onto them.

You know what? If you'd taken this to a service place they probably would have just replaced the board. No one fixes things any more.

ScottG

Thanks, @ChanW. Great post. I hope I never have to try my hand at soldering a circuit board, but I'm keeping a copy of your instructions and the Alde service manual in my T@B file just in case!

Let us know how the fix holds. Am I correct that you have one of the earlier T@Bs equipped with the Alde? Hopefully this is not a harbinger of things to come.

The Alde is a fantastic unit when it works properly, and mine has been great for two seasons. However, I can't shake the feeling that it is a far too complicated piece of equipment for my particular needs. Maybe if I take up camping when it's 5° below like some of you crazies!  :-)

jkjenn

Nice work, Chan! I stink at soldering, but I have a young friend who is very good at just this type of thing.

ChanW

ScottG, camping at 5° below, or just winter dominoes and coffee! B-) 

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.

The only problem I've had repeatedly, is the two 12V fuses inside the Alde. I've replaced one of those maybe 4 or 5 times in 3 years. Being careful that the Alde switches are all OFF when hooking up the power, either the TV or the shore power, hasn't seemed to make a difference, but not really sure.

Yep, we love the Alde. Hope it doesn't get any more temperamental. I don't know what 'replacing the mainboard' would normally cost at a service center, but it might be hard to justify the time and cost involved in doing it that way.

ChanW

boo, I considered a highly detailed tutorial, 'with 8x10 color glossy pictures with circles and arrows and a paragraph on the back of each one' (apologies to Arlo   ), but I think this info is more for the person who feels comfortable taking the Alde apart and seeing these things first-hand.

Just a few tips!

Smullis7

Thanks ChanW!!  This is great information that most would not have figured out.  Even some T@bbers that don't know how to solder may know someone who does and this would save them a ton.  While it would be fun to test out the old soldering skills from many years back, I'm hoping to never have this issue.  :-)

Photomom

If it doesn't happen again I'd write it off as maybe being marginal from the start and finally failing due to age. 

ChanW

For years I've had the suspicion that the industry was secretly using me as a tester of marginal equipment. Is it only me, or are everyone's electronic gadgets this way? 

Not really whining, kind of curious. I suppose I like the challenge of figuring out 'what is it this time?' 

ericnliz

Thanks for not only sharing ChanW, but also for the photos and descriptions as well. Curiosity question though...is that a burn on the corner of the plastic green fuse holder marked 'fuse 3.15amp?

ChanW

Darn, you noticed that!

Yep, I'm a little clumsy with the soldering iron. 

ericnliz

OOPS!

ScottG

ericnliz said:

...
Curiosity question though...is that a burn on the corner of the plastic green fuse holder marked 'fuse 3.15amp?

ChanW said:

...
Yep, I'm a little clumsy with the soldering iron. 

Good eye, ericnliz.

ChanW, at least the burn came from outside the fuse holder rather than inside--I was starting to think your Alde had bigger gremlins than a $1.19 thermistor!

Nomad

ChanW, know how you feel, I was the tester for the fridge :-(

Sharon_is_SAM

Nope, can't solder, but I can show this to a tech to help them diagnose the problem!

ChanW

That's right! You included a number of road miles in your test. Mine was only a back yard test. 
Lucky you.

PXLated said:

ChanW, know how you feel, I was the tester for the fridge :-(

DurangoTaB

I am impressed Chan!!

ChanW

Pretty lucky, I'll say. Hope it lasts! 

I'd love to know if the newer Alde boiler has the same thermal cutoff installed, with the same temperature rating.  The DF91S is rated at 91°C. I'd be curious if they perhaps changed it to one of a higher temp rating on later models.

Photomom

ChanW said:

Pretty lucky, I'll say. Hope it lasts! 

I'd love to know if the newer Alde boiler has the same thermal cutoff installed, with the same temperature rating.  The DF91S is rated at 91°C. I'd be curious if they perhaps changed it to one of a higher temp rating on later models.

That would be interesting. Can't check mine till April. 

Verna

Well, I wish I had seen this, because on January 30, 2017, my Alde was diagnosed over the phone as needing a new circuit board. I was camping without electric, so I had no heat for two days until I received the overnight delivery. It is not easy to remove the circuit board without disconnecting the gas lines, but I can tell you it can be done!  And, I can also tell you the circuit board was burnt on the rear at just about the place that this hidden fuse is located. @ChanW, my 2014 has a 2015 interior, but I wonder if I have the 2014 Alde like you.  But, now I have a later model of the circuit board, so maybe we’ll both be OK.

ChanW

Well shoot, @Verna, I don't remember you mentioning that your Alde had died.

I wonder how many others have had the same problem, and the solution was replacing the mainboard. I'm sure Alde would not recommend any soldering repairs,  though if you can do it, it's bound to be cheaper.

Did they have you send them back the old one to look at?

I'd love to know what they've done to rectify this in their design, if anything.

Verna

@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.)

ChanW

In western NY summers, the humidity minimizes the static, although I do tend to ground myself appropriately. 

I don't remember now if the thermal cutout device actually showed any indication. I'd think that because it's designed to burn out, like a fuse, it wouldn't actually burn the circuit board.

Hopefully, the problem's fixed!

Verna

@ChanW, actually, I wonder if the circuit board fuse was just a bit loose because my temps are now more consistent.

Everything is fine now.  I needed some heat the last two weekend mornings I Camp Hosted and Sunny Day and I were toasty.  I sure love the automatic set back feature of the digital thermostat—sleep in lower temps and wake up to warm T@B interior!