Weller failure

[Craig]

My Weller TCP soldering station started blowing fuses. This went on for a while, but because of work commitments just kept plugging away with occasionally replacing the fuse. It eventually refused to work at all - instantly blowing fuses. Checked pin for pin on the 3-pin locking DIN plug and found they were all shorted. When I opened the handle the pictures show the horror story. This iron was 11 years old (bought new in 2007, confirmed by date codes). The wire insulation was crumbling - it fell off the wire with the slightest touch. Trying to strip back to find a good bit, I found that the wire insulation was crumbling along the entire length of the cable - there was no good bit!

I urgently suggest that anyone with a Weller TCP bought any time around then check the integrity of the insulation inside the handle. I've been using Weller soldering stations for forty-odd years, and I have never seen anything like this.

[Murphyv310]

Two things come to mind. Possible overheating due to faulty thermostat or a partially shorted element. I'm not telling you how to suck eggs but if the reason for fuse blowing was investigated earlier you may not have had the damage you've shown.

[Craig]

Nope - no overheating. Element and magnetic switch absolutely perfect. Bought new lead (putting hope before experience).

Run from 25V 70VA transformer, rather than the Weller transformer, and it works perfectly. Absolutely perfectly. Without a bit the magnetic switch is open circuit. With a bit in place and cold the contacts close. The heater element is 12 ohms (so 24W from a 24V AC transformer. The heater is insulated from the soldering iron metal using an AVO megohmmeter to a high standard (150M at 250V). Resistance without a bit in - 10^12 ohms at 100V (so the magnetic switch is open circuit without a bit, quite correctly). With bit in, 12 ohms at room temperature.

With 100% certainty the problem was the lead - incompatible insulation. I hope they have got it sorted out properly since I bought this in 2007.

I know a thing or two about reliability and wire insulation, having had an instrument I was responsible for (the Mercury Imaging X-Ray Spectrometer) launched on 10th October by ESA on a 7 year journey to Mercury. A darned soldering iron is not, however, Rocket Science.

[Refugee]

That looks like the cable has been made up with fake wires in a good sheath.
Contact Weller and see what they have to say. It won't do any harm.
All my Weller irons were made up from several broken ones and none of the leads are like that. Some date back to the 1980s.
Your ohms law is playing up too.
12 ohms at 24V gives 2 amps and 48W.

[Craig]

That looks like the cable has been made up with fake wires in a good sheath.
Contact Weller and see what they have to say. It won't do any harm.
All my Weller irons were made up from several broken ones and none of the leads are like that. Some date back to the 1980s.
Your ohms law is playing up too.
12 ohms at 24V gives 2 amps and 48W.

Already contacted them. They were less than sympathetic. I lost patience after I sent them the photos and they went quiet.

I reckon that it is possible they procured a bunch of leads from supplier X - probably in the Orient - that were made with inappropriate insulation. If that were they case, they should have just fessed up and won everlasting customer loyalty by doing a product recall. Or an exchange.

And yes - slip of the finger on the numbers - the Weller is a 50W iron, and of course all the numbers stack up.

[Refugee]

I would have just said oops if it had been my typing

[Murphyv310]

Certainly sounds like a defective lead, do you think it was intermittently shorting out causing the fuse blowing? What annoys me is Weller soldering irons are not exactly cheap and you'd expect a better response from them than you received, at the end of the day they loose a customer to another manufacturer.

[Craig]

Certainly sounds like a defective lead, do you think it was intermittently shorting out causing the fuse blowing? What annoys me is Weller soldering irons are not exactly cheap and you'd expect a better response from them than you received, at the end of the day they loose a customer to another manufacturer.

Yes - I'd have expected a better response from Weller. And the initial intermittent short was definitely the cause of the fuse blowing. I'm going to measure the iron current today just to make sure that there is not a short somewhere in the handle when it is hot. I suspect that it will be just fine.

[Craig]

OK - with the new lead, and a chunky double C-core ex-BBC 70VA transformer that produces 4 x 6.3V it works a treat. With the windings in series it produces 26V when the magnetic switch cuts in with a current of 1.95A - so a power of 50.7W just about bang on.

So I'll adopt that transformer as the power for the iron.