Soldering station simple modification - Page 1
Forum section: electronics / beginners

author: oskimac
author_rank: Contributor
timestamp: April 21, 2019, 02:22:33 am
content: Hi! these is my first post here, so please be patient! The thing is, my main soldering iron station (a cheap ATTEN937b) despite it works fine,keeps oxidating the tips.I know there is noting bad in it.is just me keeping it on and at high temp all the time.I just dont wanna be turning the F***** knob up and down each time. So i mind a mod. put a magnet in the stand and a reed switch inside the handle rigth were the handle ends. and run the signal using the earth wire. (it short this cable whit one of the 24v ac, i dont use the earth wire inside the unit)my goal is to put the iron on a lower temp setting automatically que left in the stand.these is the board front and back. flipped:https://imgur.com/a/bEnt1mGalready added a litle relay inside the unit that is activated by the reed switch.i think i should try change the pot resistance value or something but i already try it unsuccessfully..any help?already have a ts100 that arrived broken and a usb soldering iron that i use now

author: Chriss
author_rank: Frequent Contributor
timestamp: April 21, 2019, 11:04:04 am
content: Hi!I can say I use such of soldering station over 20 year and I don't have any problems with oxidation of the tip.The tip mist be always clean. When I power of the station I always clean the tip and add a bit of soldering wire to the tip. Jus to keep away the tip from oxygen.My setup of temperature on the unit when it works is between 190c - 240c.I'm not sire does a magnet tip would even trigger the electonic to reduce the current delivered from the mosfet to the heater element. Why? Because the Curie effect if the magnet inside the tip.I tried to understand what you mean under "high temperature". Can you please define on what temperature you soldering?I have also say does I use my soldering station over 20 years and I never changed the heatin element and I use my station frequently every day 5-8h/day.My suggestion would be to setup somehow a switch in the where you put the iron pencil so the switch will trigger some electronic to reduce the current across the mosfet....Sent from my GT-I8260 using Tapatalk

author: wasyoungonce
author_rank: Frequent Contributor
timestamp: April 21, 2019, 12:38:39 pm
content: You could put in a jiggle switch. A tilt switch that turns on a timer when it’s not activated aka resting.Put this in the handle every time you pick it up it activates the switch solder station heats up.When placed in rest switch not activated, after a period, it times out and reduces iron heat.Of course the drawback is changing iron leads plugs sockets....can you get good silicon wire with enough strands? FWIW...Sent using iPhone

author: oskimac
author_rank: Contributor
timestamp: April 21, 2019, 01:39:00 pm
content: Quote from: Chriss on April 21, 2019, 11:04:04 amHi Chriss and thanks for you answer but i think you dont understand my setup or my explanation was not clear."My suggestion would be to setup somehow a switch in the where you put the iron pencil so the switch will trigger some electronic to reduce the current across the mosfet...."i already put a switch! is in the handle and is activated bi a magnet in the stand. what i was not able to figure out is how to trigger the electronic inside the unit to reduce the current across the mosfet.

author: oskimac
author_rank: Contributor
timestamp: April 21, 2019, 01:43:26 pm
content: Quote from: wasyoungonce on April 21, 2019, 12:38:39 pmhi wasyoungonce! tnks for you answer. but seem that i was not clear. i has the switch setup working fine. how you suggest the second part. reducing the iron heat.

author: wasyoungonce
author_rank: Frequent Contributor
timestamp: April 21, 2019, 11:15:03 pm
content: My idea is just too difficult to implement a Proximity switch in the iron rest is a better idea. However both could activate a 555 timer which when after it’s time period switches off iron heat via a relay. There are probably many ways to decrease the iron temp without turning it off:Vary iron temp feedback which decreases iron temp;Alter triac switching of iron heater decreasing iron heat;

author: oskimac
author_rank: Contributor
timestamp: April 21, 2019, 11:59:10 pm
content: Quote from: wasyoungonce on April 21, 2019, 11:15:03 pmYES! these are the ones i am trying to achieve but unfortunately i cant.i measure the value off the pot when is set at my desired temp. and via a relay and cutting one trace, put a resistor of that value. it didnt work.i try to copy the circuit. i am sure the trick is in the inverting input of the op amp.

author: Jwillis
author_rank: Super Contributor
timestamp: April 22, 2019, 08:58:46 am
content: If you have your normally open magnetic reed switch tied to a relay that can bypass the temp control pot to a fixed voltage divider set to a lower temp.Edit : maybe a change over reed switch that when a magnetic field is applied, it closes activating a relay. You could even have a potentimeter that you can set to the lowest desirable temperature.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: April 22, 2019, 10:58:42 am
content: Tip oxidation can be partly the result of using your Iron wrong.At what temperature are you nromally running your iron, and why are y "always running high temperature" ?One of the ways of using the iron wrong is cleaning the tip before you put it in the stand. NEVER do that !!!If you put the iron in it's stand, it should always have a bit of solder on it (from the last solder connection you made)This thin film of solder on the iron protects the tip from corrosion. Instead, the molten solder on the outside corrodes.Then, just before the next conection, you clean the tip with such a steel wool sponge, to wipe of the old solder, together with it's corrosion and you have a shining freshly tinned tip.For your modification, I see 2 easy access points to modify the temperature setting.One is between the wiper of the pot and one of it's ends.The other is somehwere in the feedback loop of the thermocouple or RTD of the iron itself.Directly on the potentiometer is probably the easiest.Take a resistor that is about twice the value of the potentiometer, and connect it between the wiper and one of the ends.If the iron now gets hotter, then move the resistor to between the wiper and the other end of the iron.If your iron now gets cooler add the switch etc.If the temperature change is too big or to small, use another resistor.You said your TS100 arrived broken.What is broken? Did you complain?One of the fun details of the TS100 is that it has a built-in motion sensor, and can reduce it's temperature when it's not used for some (adjustable) time.

author: Psi
author_rank: Super Contributor
timestamp: April 22, 2019, 11:32:35 am
content: My 2 centsYou should be able to keep your iron on for 8 hours a day at 350C and be able to solder 95% of stuff you need at that temp. The tip should last a year like that without problems.If you have to run your iron above 400C to get work done there is something wrong. Most likely you are using the wrong tip for what you are soldering. Use a bigger/wider tip and you can reduce the tempYou should check that your solder is not acid core/plumbers solder. That stuff is not for electronics and will ruin iron tips coatings. Without the coating it will oxidize fast.If you use your iron for melting plastic then stop. Some plastics will ruin iron tips coatings with just 1 exposure. Without the coating it will oxidize fast.Make sure you buy iron tips for a proper authorized seller. Digikey/Mouser/RS/element14 etc. If you get tips from ebay/aliexpress because they are cheap then that will by why they keep failing. When it comes to iron tips there are many many fakes out there that will oxidize fast and disintegrate away.You can get good tips from china/aliexpress sometimes but unless you have had and used good tips before it's hard to know if a china tip is bad or not, since you have nothing to compare against. So buy genuine tips first, then experiment with china tips later to see whats available that works

author: oskimac
author_rank: Contributor
timestamp: April 22, 2019, 02:58:54 pm
content: Quote from: Doctorandus_P on April 22, 2019, 10:58:42 amHi, and thanks for your time!as i said it was my first time asking here and i have learned a few things, don't write details that might distract the main subject of my question. the oxidation, the high temp etc. people keep answering to tose things that arent the real problem.well, i tried already the two solutions you suggested. but i might be choosing the wrong resistor because it makes no difference. i will try different ones. the thing is, i check whit the multimeter the resistance of the potentiometer but it goes from 12 ohms at 11 k and the it lower again. strange. measuring from the middle to one end.

author: oskimac
author_rank: Contributor
timestamp: April 22, 2019, 03:02:59 pm
content: Quote from: Psi on April 22, 2019, 11:32:35 amculprit of all the above

author: oskimac
author_rank: Contributor
timestamp: April 22, 2019, 03:22:24 pm
content: Quote from: Doctorandus_P on April 22, 2019, 10:58:42 amyes. i can never use it, after powering it, make some estrange noise inside (not from a burning mosfet or something, i know that sound). the sound was like (flushhhhh flushhh) like when you drop a drop of solder on water. well the thingis at certain moment i noticed the tip glowing red! then "bad tip". i complain but the seller didnt take care. (from aliexpres to usa and then to Uruguay it take more than 45 days) boy another tip and it says bad tip again. so i asume something bad whit the mosfet. i replace it and keeps burning it. the tip is new. the mosfet is new. new firmware. so i ordered sgm8551 op amp the cjq4953 dual mosfet and the tmp36 . but these is for another time

author: oskimac
author_rank: Contributor
timestamp: April 22, 2019, 06:19:07 pm
content: Well! finally i can make it work as desired. Thanks to your help.it goes from 157 to 315 C°https://imgur.com/a/1EFabwo

author: soldar
author_rank: Super Contributor
timestamp: April 22, 2019, 08:25:46 pm
content: In irons without temperature control it was common to put a diode in series and a switch would short the diode when the iron was picked up.

author: oskimac
author_rank: Contributor
timestamp: April 22, 2019, 10:08:50 pm
content: Quote from: soldar on April 22, 2019, 08:25:46 pmsomething to have in mind. thanks.

author: Old Printer
author_rank: Frequent Contributor
timestamp: April 23, 2019, 02:31:03 am
content: Quote from: oskimac on April 22, 2019, 02:58:54 pmThe thing is, we see new posters say all the time - I know it's not that, I know that's not it.... then two pages later, oh shit, it was that. Most often the obvious gets brushed over because it's too obvious, but 9 times out of 10 that's what is wrong. It really sounds like you are running too hot on a steady basis. If you know that's not the case, a brief description of how you know that, will quiet the people pestering you about the obvious. Welcome to the forum

author: KL27x
author_rank: Super Contributor
timestamp: April 24, 2019, 08:02:48 am
content: QuoteThis might be slightly difficult to explain. I might have to draw a schematic.The pot is the easiest way to utilize your reed switch.1. Figure out which direction the voltage moves to turn the temp up/down.2. Bugger that voltage in the proper direction with the reed switch; one end of the reed switch connected to the wiper of the pot, and the other to ground (or positive rail, depending on the logic/direction) with a series resistor.So when the reed switch closes, the voltage at the wiper is skewed down/up by the pulldown/up resistor.If you had room in there, you could use another potentiometer to "skew" the voltage. There are many ways to do that. You could either use it like a variable resistor and wire it just as previously described, so the amount of temp drop will be adustable. Or you could use a relatively stiffer pot (lower resistance) than the original and wire the wipers in parallel. Then you can use the pot to change the temp up or down, so you don't even have to figure it out which direction does what until after you close the thing up. What you would really want to do in this case is cut the trace off the original adjustment pot wiper and bridge it back with a resistor. Then the reed switch will connect the wiper of your auxiliary pot to the original trace, bypassing this resistor you added. So your auxiliary voltage will largely override the original signal when the reed switch is closed.This is all operating on the assumption that the original pot is producing a variable voltage between DC rails, which the value of this voltage is what is ultimately controlling the temp.But it is also possible that the pot is used in other ways, as part of a ladder, as a variable resistor. In which case you have to figure that out and adjust your game plan. Figuring out what the rails are and seeing if the pot is attached to both power and ground or not would be a good starting point.

author: oskimac
author_rank: Contributor
timestamp: April 24, 2019, 10:32:56 pm
content: Quote from: Old Printer on April 23, 2019, 02:31:03 amYes! i totally agree what you says. and is true.but my point was that i dont care about the tip or the oxidation or how to solder or anything else. I just wanna mod my iron to be in a "sleep" state when in the stand. And was asking about that. thanks!

author: Psi
author_rank: Super Contributor
timestamp: April 25, 2019, 10:28:50 am
content: Your reed switch needs to adjust the temp sensor circuit in the handle so the electronics thinks the iron is hotter than it really is.That way the electronics will let the element cool down to some degree.You need to investigate your soldering iron handle to find out what kind of temp sensor it uses.Then measure it to see what property changes with temp, resistance, capacitors etc. and in what direction.Then you can figure out what you need to do with the reed switch to make it read hotter than it is.

author: KL27x
author_rank: Super Contributor
timestamp: April 25, 2019, 05:56:50 pm
content: QuoteNo it doesn't "need" to. Apparently, you did not read my directly preceeding post and/or maybe I am not explaining it very clearly.It is arguably better to put the reed switch in the stand and make it tweak the actual set temp. For one, if this is one of the irons with a digital readout, you can see it changing so you can figure out when it's working reliably. And you can also see/adjust the actual sleep temp you want. But also because the reading from the heater is probably very sensitive and gets amplified and buffered by opamps before it reaches the control circuitry. Making an adjustment there will be more twidgy. You would also have to stuff circuitry in the handpiece, assuming there is room for this. And how are you going to make the reed switch react to the stand when you are putting the switch somewhere in the back of the handle... you have to make a pretty funny stand.The pot on the station creates a straightforward, static voltage signal that is the input for a comparator or an ADC with no further signal processing. Tweaking it very precisely is child's play. And you have ample internal space and external real estate to at add additional switches, pots, indicators, circuitry to the station. You also have access to the power supplies. The handpiece has the heater output and a (likely) thermistor in/out that are two nodes in a resistor ladder. And a ground/earth, perhaps. The handpiece won't have the DC rail that feeds the logic circuitry, in most stations.So not only is there more than one way to skin this cat, the way you have deemed to be the "only" way has no immediately obvious benefit, IMO.Well, there's one benefit. If you could get the reed switch in the handle to work as you want it to, you would not need to wire your holder/stand to the station. But there are a lot of limitations if doing it this way.

author: Jwillis
author_rank: Super Contributor
timestamp: April 26, 2019, 07:00:13 am
content: This is what i would do.Simply desolder the temp control potentiometer bend up to the wiper pin and either on of the outer pins. Solder wires to pins ,solder wires into PCB holes and one wire to unbent pin of Potentiometer .Soldar wire to pin 2 of DIN plug .Wire up standby pot and relay as shown.Now you can have the reed switch in the stand or in handle .Makes no difference except attaching a suitable magnet to handle may be awkward.

author: KL27x
author_rank: Super Contributor
timestamp: April 26, 2019, 08:02:40 am
content: This is what I envision as a basic, ELI5 schematic of what I probably failed to describe with words.You add R3 series resistor on the temperature pot wiper (R2). You insert your additional potentimeter (R1) to adjust the sleep temp to w/e you want.Of course if you had a dual pole (or is it throw?... I'm throw/pole-dyslexic) reed switch, you could use that instead of adding R3. This would make the sleep temp completely stable despite any subsequent adjustment of the set temp, and would not introduce any noise in the set temp. I don't even know if they make dual pole (throw?) reed switches.()OP: If you cut power with a relay... your iron goes cold. Or you have to make a new thermostatic control to make it keep a sleep temp. Just use the controls that are already in there, dude.Jwillis, I have to admit I'm too tired to figure out what you even did there. Kinda complicated.

author: Jwillis
author_rank: Super Contributor
timestamp: April 26, 2019, 09:43:44 am
content: There are change over reed switches with 3 pins.Pin 1 is common ,pin 2 is open and pin 3 is closed.But I don't see it being necessary here ,since while the iron is in use ,the relay is simply not active.Provided the relay doesn't draw to much current .the small reed switch he has would probably work provided its normally open. A small 0.5 amp relay would be more than enough.A solid state relay would be even better.Not sure what voltage this iron runs on ,12v or 24v.Since the control pot is a voltage divider ,a single resistor approach might not work.Looking at the diagram I am under the impression the unit is externally powered so any feedback noise would be negligible.But I would try to keep the extra wiring as short as possible inside the enclosure.

author: Psi
author_rank: Super Contributor
timestamp: April 26, 2019, 10:35:33 am
content: Quote from: KL27x on April 25, 2019, 05:56:50 pmThat's possible but tricky, If the reed switch is in the stand then you need the magnet in the iron handle.A magnet will lose it's magnetism if it gets hot so you have to place the magnet away from the hot end of the handle.That is a problem because the hot end is what touches the stand where the reed switch is.

author: KL27x
author_rank: Super Contributor
timestamp: April 26, 2019, 05:04:54 pm
content: Psi, yeah, I guess I didn't think that thru.Jwillis, the way I would do it there is no relay.Sleep temperature is achieved the same way regular operating temperature is achieved. It's like you are turning the knob on the station down and back up. The station already has the circuitry to react to that.There's no need to use a relay. The station already has a triac in there to switch the heater via a temperature controlled circuit. You just have to change the set temp to an alternate setting.If you have a Space Shuttle in front of you, and you want to rig it to launch at 10 oclock, you hook an alarm clock to the Launch Button that has already been designed into the billion dollar vehicle. You don't jury rig a match to go off under the booster.

author: oskimac
author_rank: Contributor
timestamp: April 27, 2019, 07:43:53 pm
content: people! it has already been done. just the rele adds a series resistor at R3 in schematics. about the different approaches , the reed inside the handle was the best. due to space limitations. and the fact magnet will loose efficiency cause of the temp if was in the handle. ALSO my stand is separated from the rest of the base. so in my solution there are no cables from one side to another.