Weller Wtcpt soldering station??? - Page 1
Forum section: electronics / repair

author: kgavionics
author_rank: Regular Contributor
timestamp: May 28, 2016, 07:03:25 pm
content: hi guysi have a problem with my weller wtcpt soldering station.the unit is not heating up enough.so i took the unit apart and i was shocked to find only a transformer and a capacitor.Why they call it Temperature controlled soldering station? there no temperature control loop at all.can someone enlighten me this subject please?thanks in advance

author: linux-works
author_rank: Super Contributor
timestamp: May 28, 2016, 07:07:26 pm
content: its all in the tips, iirc. curie point and all that.magnetism causes the tip to get heat and then no heat via direct contact that is temperature-sense based.the tips have all the magic.

author: kgavionics
author_rank: Regular Contributor
timestamp: May 28, 2016, 07:26:41 pm
content: Quote from: linux-works on May 28, 2016, 07:07:26 pmthanks for the heads up linux-works.so the tip is not heating up well, because its defective?

author: Gyro
author_rank: Super Contributor
timestamp: May 28, 2016, 08:08:53 pm
content: It's most likely that it's the contacts on the magnetic switch (the thing that the capacitor is soldered to). It's basically a long tube that runs down the centre of the element with a sliding magnet inside and a rod and spring to actuate the contacts. The magnet is attracted by the slug on the back of the tip, closing the contacts. When the slug reaches its curie point it stops attracting the magnet and the spring opens the contacts.It's an accurate and reliable system, but the switch contacts themselves can get dirty, or the magnet-switch assembly can go faulty (magnet sticking or whatever) or just 'tired'. Once you've checked all the other things, cable connections, plug, heater continuity etc then you can try opening the top of the switch and try cleaning the contacts.Sometimes it's as simple as the handle not being assembled correctly, the whole switch assembly is sprung loaded so that it can slide to touch the rear of the tip. If the assembly sticks too far back in the barrel then the magnet will be too far away to be attracted by the slug. As you insert the tip into the end of the element you should clearly hear the click of the switch closing, if that doesn't happen then there's a switch problem.

author: Ian.M
author_rank: Super Contributor
timestamp: May 28, 2016, 08:27:36 pm
content: I did the maintenance for a workshop full of Weller TCP irons, mostly used when we got them, for about 10 years so I have seen just about every problem they can have.Running too cold is extremely rare - unless the bit is badly corroded and the Curie point pellet is not making good thermal contact. The commonest fault is total failure to heat caused by burnt or dirty Magnastat switch contacts or occasionally by mistaken substitution of a bit that looks similar but doesn't have a Curie point pellet to activate the Magnastat. Another nasty fault is gross overheating caused by a seized or contact-welded Magnastat switch jammed on - the barrel can get hot enough to start glowing in a darkened room and if you don't catch it soon enough, it is likely to damage the handle and the mounting frame inside it.IIRC the handpiece uses a 24VAC supply, and as its nominally 50W the DC resistance should be between 11 and 12 Ohms, with a cold bit in. With no bit in, the Magnastat switch opens and the iron shold read open circuit measuring from its base station plug. The third pin of the plug is Earth to the barrel covering the element. If you do some ohms testing you can see if the problem is the iron or the base station without having to dismantle the iron.

author: kgavionics
author_rank: Regular Contributor
timestamp: May 29, 2016, 03:40:29 am
content: Thank you guys.i fixed the problem, it was just a loose wire.

author: Gyro
author_rank: Super Contributor
timestamp: May 29, 2016, 02:15:27 pm
content: Glad it wasn't an expensive switch or element replacement. I'm sure it will serve you well.