Crafty Home Repair Thermal Fuse - Melted internals!

[gbutter]

Hi guys, first time poster here, long time lurker and S&B user.

My Crafty has the Red Yellow blinking light error which apparently indicates a thermal fuse issue.

I've been down the rabbit hole of finding the much-used repair video, ordering t6 screwdrivers and a thermal fuse, and I was ready to take the plunge. I've also been in touch with @JCat about replacement battery packs, but in the meantime, I thought I'd give this repair a shot.

Opened up the Crafty like in the video (link below) and found that I couldn't pull the circuit board out of the unit because somehow part of the internal black plastic seemed to have melted onto one of the light blue wires. I don't have any specialized knowledge and was just hoping to follow along with the video, but I'm not sure how to handle this curve ball, photos below. Any advice? Does this particular wire look safe to be a little rough with and pull out? Should I find an electronics guy to replace this wire? Any advice appreciated.

Also, the fuse I ended up getting here in India is 210C rated. Would that work?
Here's the repair video:

Thank you!

Alright, poking around a bit more after posting, and most of the thing has come out, and I now have a better view of the wire that's stuck. Attaching more photographs in case anybody can advise me on how to move forward.

Also, does this particular melted cable need to connect back to the circuit board, or does that metal bit just hang free?

Thanks again in advance!

For anyone following along with my play by play from home, I used flathead screwdriver to slowly chip away at all the black melted casing until I managed to free the wire. Used a combination of videos to reassemble things and am charging the crafty.

There's no red/yellow error light yet, so I'm wondering if that melted wire might have been the cause somehow? I was getting battery overheated and faulty thermal fuse error messages initially, but perhaps this wire excavation might help with those?

Anyway, let's see how much this thing charges up and then if it actually works.

For future crafty DIY-ers, here are the videos I used when I was panicking about what goes where:
- Vaporizers Reviewed Teardown - very high res and useful:

- @JCat battery replacement video -

- Flashing light repair video -

 

[blackstone]

Well, basic electric knowledge tells me that when the voltage is halved, your current is doubled.
And high current at weak points in the circuit can result in, among other things, excess heat.
Besides the smaller sized layout, this in my opinion is where they found challenges with early versions of the single cell Crafty, even while using a lower wattage heater than the 36 watt heater of the dual cell Mighty.
(My rough calculation shows the Crafty might run at about 7.5 amps, while the Mighty could run at around 5 amps by having more voltage available, or as low as 3 amps using the 12volt charger)
It might have been an unintended cause of heat related issues in those early Crafty models.
At least one connection inside is a gold pressure spring contact from memory of pictures I saw.
Although I've never seen melting or a wire that went as astray as yours. I wonder if your casing will still function properly for you.
I think the fact that you were at the point of needing a new battery cell, or possibly running at lower voltages than normal may not have helped but that's only a guess.
At some point, perhaps 2017, Crafty models appeared to become a lot more reliable and not overheat and/or blow the safety temperature fuse, maybe you do have an earlier one.
The current should be at normal levels with a new battery, although still quite high so you'll need to be really sure of those connections for it all to work reliably at this stage.
Not sure about the fuse question, what was the old fuse rated for?
What hours or how old is the device now?

 

[gbutter]

Thanks for the reply @blackstone.

I think you are right about the current doubling - perhaps a drop managed to dislodge the wire from it's circuit board connection, which subsequently got pushed up against the chassis on the inside, and ended up generating extra heat and melting.

That might explain why I was not able to get the device to power up from rest (red-yellow flashing error), but I was able to sort of jumpstart it by plugging in the usb cable and turning on the power button right as the vibration happened. It was a gamble but it would half work - perhaps this unruly behaviour of mine compounded the problem from just a dislodged wire to the flambé horror story I found within. The wire itself was one that I put into one of the two golden slots in the centre of the PCB - maybe these are the gold pressure spring contacts you mentioned.

For now though, I am pleased to report that even without replacing the fuse, the crafty seems to be functioning reasonably well! All the abnormalities around charging and power up errors might have been caused by the dislodged wire and the melting, because it is charging enough for about 2.5 bowls and isn't giving me red yellow flashing light anymore. So, I am quite chuffed.

To your point though, this crafty was actually purchased in 2018, and I think it's a later version with a slightly reinforced chassis design near the bowl. It does have about 230 hours on it, but I have a strong feeling that it was a physical drop at the root of the problem. Oh and the old fuse is rated for 184C I think, but this new one that I bought is 210C. Not going to mess with it now though. If it ain't broke...

 

[JCat]

Hi @gbutter,

Been just super busy so didn't have a chance to reply here, but here's some thoughts on it.

I had a look at your picture, and I had a hard time figuring out what's going on; where's the thermal fuse? It appears to be missing ... that metal clip is usually connected to one end of the thermal fuse, then the other end of the thermal fuse goes into the circuit board (maybe the prior owner removed the thermal fuse?)

Here's a picture of what it looks like on a "non-melted" assembly (from a broken unit I have--dead circuit board)

Glad to hear you got it up and charging though! That's a good sign

I have more parts in stock (wire and connectors, I still had batteries), and will try to get some battery packs assembled this weekend.

 

[gbutter]

Hey @JCat, thanks for the reply.

So I didn't end up opening the plastic case around the heating element at all - and if I understand correctly the thermal fuse is inside that right? In which case, presumably, it is still there. the melted wire looked like it wanted to curve around the rest of the assembly and enter the circuit board, so that's where I put it. Right next to the hole that the wire with the translucent casing is going into on the circuit board. Does that make sense?

I'm hoping it does and that I haven't screwed something up worse than before hehe.

 

[JCat]

It does make sense ... but that metal clip is only inside where it connects to the fuse ... there is none on the other end ... that’s why I was saying that it looks like maybe the prior user removed it.

it looks like they cut the fuse and then used that cut end to insert into circuit board and bypass the fuse. (Maybe not the best idea as is evident by your melted case )

 

[gbutter]

Hrm, that would be super strange since I bought it new and had to cut open the label. Maybe in one design this clip came up on both sides of the wire?

 

[danielsdelgado]

Hi guys, I got replace my thermal fuse but my device still has more de 55% battery. Any tips how can I drain the crafty battery before replace the thermal fuse? Thank you

 

[Green Kiwi]

,I don't understand.
Why would you want to drain the battery,after replacing the thermal fuse?.
but, anyway, what I do think your crafty needs is a reset.
This is simply done by holding the on/off button for 10 seconds.
please post back, I reckon we all can learn of your case..
have one on V....o!.

 

[danielsdelgado]

Hi buddy, I think I need drain the battery before to change the thermal fuse but as my device don’t turn on any more I don’t know how to drain it tu do a safe exchange of thermal fuse. Thank you

 

[badbee]

Hi buddy, I think I need drain the battery before to change the thermal fuse but as my device don’t turn on any more I don’t know how to drain it tu do a safe exchange of thermal fuse. Thank you

You must be misunderstanding. You can never drain a Li Ion cell below 2.5 V and whether is at that voltage or 4.0 V is an irrelevant detail. You can work on it as it is without further draining.

 

[blackstone]

Hi guys, I got replace my thermal fuse but my device still has more de 55% battery. Any tips how can I drain the crafty battery before replace the thermal fuse? Thank you

I'm not sure if the Permanent bluetooth or Find my Crafty features would work if you're in a fault mode as I haven't experienced such problems, but those may be options to slowly take down the charge level, if it's even needed.
I had a skim through that fuse replacement video, but it didn't seem to mention lowering the charge level first.

 

[1800]

Did anyone change the thermal fuse on Crafty+?

The above linked video details the process for the original Crafty but supposedly on the +, the fuse is soldered on hence making it harder to change.