Weller soldering iron.

[sigmolio]

I hope this is not cheeky but I'm having problems with a soldering iron that I use, not for electronics but stained glass. I have found it difficult to get help anywhere and if you don't mind, perhaps you can help. It's a Weller 101W, so 100 W iron with a magnastatic temp control. it has packed up after very little use.

Multimeter shows the heating element at 0.538K ohms.

The cap is marked as 0.01micro farads and reads 15.12nF on meter.

The switch contacts engage and disengage when the tip is inserted and removed. It's had so little use that I don't see how it could be corrupted contacts.

Any help or advice gratefully received.

[Silicon]

I did a search for 'weller magnastat' and found a web site article 'weller magnastat autopsy and repair' at the codeandlife.com website.

Are there two heating elements?

[duncanlowe]

Have you used your multimeter, to check continuity through the eintire circuit? As in does it show the resistance, at the plug itself?

The contacts on the switch can go faulty, especially if not used but stored in a damp place. Also worth checking the fuse, and loose connections in the plug.

In general these are reliable irons.

[Leon Crampin]

I have a 100W Weller which is pretty ancient - maybe similar to yours. A long time ago the thermostat failed o/c rendering the iron useless, with no spares apparently available.

With nothing to lose, I bypassed the thermostat and fitted a diode in series with the element. It works perfectly well and seems no worse for losing its control facility. The temperature is just right for big soldering jobs and the bit has not eroded much - so it's not far too hot. It has been in use for the last 10 years for the occasional heavy job.

It also now no longer randomly triggers my Tek when investigating low level signals.

Leon.

[Uncle Bulgaria]

What type is it? The Weller Magnastats are still current. I have a TCP with PT bits. The different tips have different Curie temperatures which affect when they change their magnetic properties. You'll find the temperature stamped on the changeable tip. The number part (say PT7) is the temperature in hundreds of fahrenheit (in this case 700F or ~370C).

Different adaptors allow for different bit styles. This page from Rapid explains it.

New parts are available, but TCP irons also regularly come up on eBay or local auctions, Facebook Marketplace, Gumtree etc. for very little money.

You can post a picture to help out the experts here, too.

[Craig Sawyers]

Watch the cable between the Weller Magnastat iron and the power supply. The cores of mine went as hard as biscuit, crumbled and shorted out. And burned out the power supply transformer. Piles of acrid smoke - they had wound the transformer using solderable wire, which by definition is a low temperature insulation.

The unit had occasional hobby use - not a production environment.

Weller walked away. No representation by me made any difference to their position. Tough luck customer.

So I bought a Metcal. Other brands are available that are not Weller.

Craig

[Diabolical Artificer]

You don't say if the iron is new or an old one new to you. If the former can you not return it?

If the latter, have used checked the fuse in the plug?

Andy.

[CambridgeWorks]

Ref post 5 & 6. This iron is a direct mains powered one. There was one sold recently on ebay with the fault of not powering on, so might be a common problem?
Rob

[Steve_Bell]

I have the same iron, used for the same purpose as yours. I measured the element resistance and it was 0.540K, so it looks like your element is OK. Sorry I can't help further with your problem though.

[Station X]

With the iron cold what resistance do you measure between the Live and Neutral pins of the mains plug? If you see an open circuit work your way round until you locate the break. My money's on dirty contacts.

[Leon Crampin]

I don't think the thermostats on the mains voltage Weller irons are reliable. I should have made it clear that fitting a diode to a transformer driven iron is not an option due to core saturation.

Leon.

[sigmolio]

Originally Posted by Silicon

I did a search for 'weller magnastat' and found a web site article 'weller magnastat autopsy and repair' at the codeandlife.com website.

Are there two heating elements?

Just one

[sigmolio]

Originally Posted by Craig Sawyers

Watch the cable between the Weller Magnastat iron and the power supply. The cores of mine went as hard as biscuit, crumbled and shorted out. And burned out the power supply transformer. Piles of acrid smoke - they had wound the transformer using solderable wire, which by definition is a low temperature insulation.

The unit had occasional hobby use - not a production environment.

Weller walked away. No representation by me made any difference to their position. Tough luck customer.

So I bought a Metcal. Other brands are available that are not Weller.

Craig

its a Weller 101w AC so no transformer

[Maarten]

Just for completeness sake, using a diode instead of the thermostat, will turn a 100W soldering iron into a 50W one. Which will work perfectly fine for most normal applications, but the extra power isn't there when needed anymore.

If the thermostat is not repairable and not avalilable anymore, you might want to add a boost switch in parallel to the diode.

[sigmolio]

Originally Posted by Diabolical Artificer

You don't say if the iron is new or an old one new to you. If the former can you not return it?

If the latter, have used checked the fuse in the plug?

Andy.

10+years old but hardly used . checked fuse and connects in plug, all good.

[Station X]

This should be a very simple fault to diagnose, although fixing it may be more difficult.

You just need to prove continuity from the Live pin of the mains plug to the Neutral pin of the mains plug.

[Leon Crampin]

The 100W Weller dissipates more than 100W when actually energised. I would estimate that the rated 100W is the dissipation at idle, and my recollection is that the duty cycle at idle is about 2:1 off to on. So, possibility a 300W element if I'm right.

Assuming the Weller element has a near zero coefficient of resistance vs. temperature, as with nichrome, a measurement of the element resistance will give the answer.

Leon.

[Station X]

538R according to post #1.

98.32 watts at 230VAC.

[Wellertcp]

The burning question (excuse the pun!) has been asked by StationX; the test to do is to set your meter to resistance and connect across the L and N pins of the plug. (With the iron NOT plugged-in obviously)
The meter should read the resistance of the element, plus possibly a bit for wire resistance, internal connections, etc.

You say that inserting the tip attracts the magnastat, so mechanically that sounds ok.

My money is with Station X; dirty contacts.

My experience is with the 24V Wellers, but, same thing different gravy.

IME, the 24V Wellers draw more that their rating; so my 50W Wellers draw about 55W, (the early) 48W Wellers draw just over 50W, 45W Wellers draw about 50W, etc.
Also IME, when the magnastat is inactive (Curie point) the cap across the contacts will still pass some current through the element.

[factory]

Originally Posted by Craig Sawyers

Watch the cable between the Weller Magnastat iron and the power supply. The cores of mine went as hard as biscuit, crumbled and shorted out. And burned out the power supply transformer. Piles of acrid smoke - they had wound the transformer using solderable wire, which by definition is a low temperature insulation.

The unit had occasional hobby use - not a production environment.

Weller walked away. No representation by me made any difference to their position. Tough luck customer.

So I bought a Metcal. Other brands are available that are not Weller.

Craig

Same thing happened at work with a Weller made around 2008-ish, it was like Weller had found a source of vintage rubber cable, it went hard, crumbled & shorted, we spotted it before the PSU went into thermal runaway mode.

Never had a problem with the older ones, which were still in use years after this incident. The Pace irons at home & work never had this trouble, we have recently got a Metcal at work, much better than all the old stuff, still waiting for them to re-instate a air line for the de-solder part.

David