|
Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
|
Thread Tools |
26th May 2020, 7:56 pm | #1 |
Diode
Join Date: Apr 2015
Location: Stevenage, Hertfordshire, UK.
Posts: 5
|
Weller TCP soldering iron
Hi I have a Weller TCP soldering iron that started playing up and overheating and after having a read around I took apart the thermostat switch and cleaned the contacts and it seems to be behaving itself again.
I noticed that some TCP irons have got a capacitor across the switch, presumably to reduce arcing and stop the contacts welding shut. Would it be worth adding a capacitor to my iron to extend the life of the switch? What type of capacitor do I need? |
26th May 2020, 8:08 pm | #2 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
|
Re: Weller TCP soldering iron
In light of previous threads, please don't turn this into an A-Z of soldering irons
|
26th May 2020, 8:29 pm | #3 |
Nonode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 2,529
|
Re: Weller TCP soldering iron
As far as I know the capacitor is to reduce interference when the thermostat operates. Thermostat contact welding seems to be a well known issues which is why spares are available.
|
26th May 2020, 10:48 pm | #4 |
Dekatron
Join Date: Nov 2010
Location: Oxford, UK.
Posts: 4,942
|
Re: Weller TCP soldering iron
I have two Weller TCP soldering irons.
On one the connecting lead internal insulation broke down (went like biscuit - the pictures are in another thread on here somewhere) and, long story, burnt out the transformer. Weller refused point blank to accept responsibility. So I bought a new lead, and in true Franken-iron style used an ex-BBC valve heater transformer with 4 x 6.3V windings wired in series. The entire blue body, much modified is screwed on top of the massively overrated transformer. I then made the mistake of buying a new one around a year ago. That is incompatible with the older bits - so needs me to buy a range of bits that I typically use to suit. And that one has started to play up too! Goes cold - a good whack of the handle starts it working again. Internally it looks fine, but there must be a problem with the magnetically operated switch. I take Bill's point about A-Z, but twice bitten with declining customer care and flaky quality from Weller, I will never buy another of theirs. Craig |
27th May 2020, 12:24 am | #5 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
|
Re: Weller TCP soldering iron
Mine has one, I thought they all did!
I assumed for arcing, but interference is more or less the same thing in a different guise. |
27th May 2020, 6:58 am | #6 |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,639
|
Re: Weller TCP soldering iron
Mine had a small RIFA X type, finding a replacement of the right size was tricky amongst my spares. An X type would be best I guess.
Andy.
__________________
Curiosity hasn't killed this cat...so far. |
27th May 2020, 10:30 am | #7 |
Octode
Join Date: Feb 2009
Location: Bletchley, Buckinghamshire, UK.
Posts: 1,205
|
Re: Weller TCP soldering iron
I have never thought of this before, but I wonder if a worn-out RIFA is the reason why the switch contacts eventually suffer from the effects of arcing and need cleaning up?
At only 24 volts I have never seen one go *bang* (yet...) but the capacitance might gradually fall with aging in the same way it does with mains voltage transients. |
27th May 2020, 12:39 pm | #8 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
|
Re: Weller TCP soldering iron
Quite possible, that is how they work. Repeated transients are more or less guaranteed!
|
27th May 2020, 12:52 pm | #9 |
Dekatron
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 5,263
|
Re: Weller TCP soldering iron
I thought the early ones didnt have the capacitor and later ones did. I assumed that it was for EMC compliance in light of legislation.
I've never understood why a capacitor & resistor is not used. For example if a capacitor across a switch reduces rfi or sparking when the contact opens, by way of reducing the rate of rise of voltage, (dv/dt) why is it ok to close the contact and allow a rapid discharge of the same capacitor?
__________________
Kevin |
9th Jun 2020, 8:36 am | #10 |
Heptode
Join Date: Jul 2014
Location: Boston, Lincolnshire, UK.
Posts: 993
|
Re: Weller TCP soldering iron
I'm also just 'refreshing' a TCP iron, with a cracked RIFA cap - anyone know where I can source a suitably sized replacement ?
The existing RIFA is marked "PME 261 KA", 400V-/220V-MP, 40/070/56, and it's a small ca. 10mm lead pitch size. I'm reading it as 47,000pF, 220VAC, but most of the equivalents I'm seeing online are 15 or 20mm lead pitch. Alan |
9th Jun 2020, 8:49 am | #11 | |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,061
|
Re: Weller TCP soldering iron
Quote:
(Personally, I'd use capacitor in series with a few ohms of resistor, as you say). Weller irons - I have a mains-driven Magnastat which occasionally fails to open, the iron glows a very dull red. And I use a couple of 24V TCP irons. No trouble except a fatigue-broken lead near the connector. |
|
9th Jun 2020, 1:48 pm | #12 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,803
|
Re: Weller TCP soldering iron
The early TCPs without the capacitor showed no worse problems with sticky thermostats. I think they are entirely for EMC reduction.
David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
10th Jun 2020, 6:14 am | #13 |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,639
|
Re: Weller TCP soldering iron
Found this one Alan at Farnell - https://uk.farnell.com/kemet/r463f24...ial/dp/2495809 checked datasheet - = 10mm lead spacing. Here's the page for all 47n X series caps - https://uk.farnell.com/c/passive-com...itance=47000pf
Andy.
__________________
Curiosity hasn't killed this cat...so far. |
10th Jun 2020, 11:16 am | #14 |
Heptode
Join Date: Jul 2014
Location: Boston, Lincolnshire, UK.
Posts: 993
|
Re: Weller TCP soldering iron
Cheers Andy - just what I needed, thanks
|
14th Jun 2020, 9:47 pm | #15 |
Hexode
Join Date: Apr 2017
Location: Buderim, Queensland, Australia.
Posts: 428
|
Re: Weller TCP soldering iron
Weller TCP User Operation and Spares Leaflet, from about 1990.
I have two of these units which have worked perfectly for thirty years. . |