DJ's souved and dissected Weller carcass should be retrieved from the ---Bin Of Unfused Shame--- and reassembled with a suitable 120/120 CT to 24 volt isolation transformer
($35 to $60 depending on VA requirements > any decent cheapie tranny should be better enameled than the honey coatings on the crusty deceased one,
and come stock with a thermal fuse fitted with a -MUST- recommendation to use a primary fuse and the value. Reference: Altronics and Jaycar catalogues)
...
I'm betting a properly rated fuse will pop faster, perhaps crack or shatter, and the unit will survive unscathed and back to work
Its the combo of bodged in secondary side fusing and no primary side fusing that doesn't inspire confidence. The secondary side polyfuse positioned where the transformer can heat it is IMHO legitimate to reduce the risk of cooking the transformer as line voltage polyfuses aren't cheap or common, but why in the nine billion names of god is the extra ordinary fuse on the secondary side not the primary side?
The bottom line is that Weller can't admit they've done something wrong (for potential liability reasons); I'm actually surprised that a lot of people here think that the response wouldn't have been pretty much exactly what it was.
Common sense tells us that something which is apparently so blatantly bad should be easy to prove, but no real quantifiable evidence has been brought forward. Considering this has been going on for many pages now, you have to wonder why this evidence is consistently absent. That there is no real issue seems ever more likely. Angrily disagreeing doesn't change that. Providing something tangible does.
Its the combo of bodged in secondary side fusing and no primary side fusing that doesn't inspire confidence. The secondary side polyfuse positioned where the transformer can heat it is IMHO legitimate to reduce the risk of cooking the transformer as line voltage polyfuses aren't cheap or common, but why in the nine billion names of god is the extra ordinary fuse on the secondary side not the primary side?
All for the sake of a few cents in the BOM of a product which is being promoted using $100,000 stands at large trade fairs (alongside competitors who've seen Dave's video and will happily tell their clients about it).
Its the combo of bodged in secondary side fusing and no primary side fusing that doesn't inspire confidence. The secondary side polyfuse positioned where the transformer can heat it is IMHO legitimate to reduce the risk of cooking the transformer as line voltage polyfuses aren't cheap or common, but why in the nine billion names of god is the extra ordinary fuse on the secondary side not the primary side?
I argued against this earlier in the thread, there is no thermal coupling from PTC to the core or windings at all, so I don't think it will do much.
There is a reason when a thermal fuse is used on a transformer it is either buried inside the windings or directly coupled to them then tape over top.
Some estimations:
Fuse is 7A (trip of 14A), and secondary is using approx 3A (peak), so 20% of rating. A PTC curve shows we would have to hit over 115C to reduce the fuse rating to 20%, who knows what the winding temp would be at that time, over 200C? I don't think anything could cause the transformer to heat up that much and not already be blowing up/burning something else already.
The secondary side actually has two fuses, plus thepolyswitch. One is on the PCB.
The secondary side actually has two fuses, plus thepolyswitch. One is on the PCB.Yes. hence my description of the black wire ended one as the 'extra ordinary fuse'. Knowing that there's a fuse on the PCB, its sheer presence hanging off the secondary terminal indicates a design process SNAFU.
Did anyone note the ratings of all the fuses?
All for the sake of a few cents in the BOM of a product which is being promoted using $100,000 stands at large trade fairs (alongside competitors who've seen Dave's video and will happily tell their clients about it).
I'm waiting for some smart competitor to realise the marketing potential here and a make video with one of their product designers tearing down their product
and showing how they have a primary side fuse and how they select the rating and test it etc, and how they take safety more seriously than their competitor
SCNR
The secondary side actually has two fuses, plus thepolyswitch. One is on the PCB.Yes. hence my description of the black wire ended one as the 'extra ordinary fuse'. Knowing that there's a fuse on the PCB, its sheer presence hanging off the secondary terminal indicates a design process SNAFU.
Did anyone note the ratings of all the fuses?
Both are 4A. Why you'd have two 4A fuses in series is beyond me.
Please don't intentionally misattribute quotes to people.
the owners of Weller soldering irons now know that there's a safety issue.
For the dozenth time now, and I'll keep saying it every time someone brings it up, if there is no potential issue then why does Weller have a primary fuse on almost all of their other (identical function) products?
For the dozenth time now, and I'll keep saying it every time someone brings it up, if there is no potential issue then why does Weller have a primary fuse on almost all of their other (identical function) products?Say it as many times as you like. It doesn't make it any more true that there's an issue with this stations OR all the other appliances out there without a fuse as you seem to suggest.
For the dozenth time now, and I'll keep saying it every time someone brings it up, if there is no potential issue then why does Weller have a primary fuse on almost all of their other (identical function) products?
Nope.
The problem is that post-Dave's-video, the owners of Weller soldering irons now know that there's a safety issue. If they have any sort of a conscience then they have to be a lot more careful about selling/giving them to random strangers.
It's not just a simple case of them not working when they arrive after a mixup, it's about them going up in smoke within seconds of being plugged in.
Would you still sell them on eBay, knowing what happens?
A safe failure isn't a safety issue.
The secondary side actually has two fuses, plus thepolyswitch. One is on the PCB.Yes. hence my description of the black wire ended one as the 'extra ordinary fuse'. Knowing that there's a fuse on the PCB, its sheer presence hanging off the secondary terminal indicates a design process SNAFU.
Did anyone note the ratings of all the fuses?Both are 4A. Why you'd have two 4A fuses in series is beyond me.
Smoke pouring out is not a safe failure.
Smoke pouring out is not a safe failure.Didn't we discuss this before? If it were to be massive amounts of smoke it may be a problem
Dave's words were "big wide billow of smoke" and "...by the amount of smoke that escaped from this thing, it's not going to be pretty".
Dave's words were "big wide billow of smoke" and "...by the amount of smoke that escaped from this thing, it's not going to be pretty".I think he also reported the smoke detector not going off despite it happening the office building, but maybe hecovered up the sensor. I'm not sure.
How do you guarantee the safety of a transformer that smoked the enamel of it's primary windings? That stuff is isolating every winding. It's no surprise that pretty much everyone else, including weller on more expensive models include a well-known safety device: a fuse.
Unless weller reponds something that makes more sense, i will think that they removed the fuse for strictly economical reasons. If weller had some kind of transformer that didn't needed a fuse, why would they use it only on their cheapest models? Because the more expensive ones do have the fuse, which wouldn't be needed with the "better transformer from the cheapest models". How would a blow-proof transformer cost less than a fuse anyways?
Makes no sense.