In some designs, the tip is deliberately isolated from the mains supply and the earth. This "double insulation" approach means that the user is less exposed to electric shocks and equipment failure, i.e. accidentally goes soldering a live board and BANG! The manufacturer is just hedging their bets! At least there's an option on the PCB though as maybe some countries demand it?
Very good comment imho. I'd say: Either ground it properly or build a floating power supply with reasonably low common mode noise. Or add a capacitor to ground or something. Can be done. Not a good comparison, but my trusty old Agilent E3632A linear bench supply measures ~2V AC/1uA... I guess it will be more difficult with a SMPS, generally speaking. I wouldn't feel comfortable using this station tbh.
Thanks for sharing this! On a side note: the Fluke 87v "LO" function is a low pass filter for weeding out higher freq noise from VFDs and inverters. Unfortunately, it doesn't have a "LoZ" function for low impedance.
Probably was intended to have a 1k PTC thermistor there, and it was cost cutted out. A 1k PTC will work well, low resistance, and limits current if you accidentally touch a voltage source, and the PTC side will also limit current as it heats up. A second 2k unit in parallel, with a small bridge and a red LED, will show if there is high voltage drop across the resistor, though not really needed.
I am not an expert on how the 245 works but I think wiring the negative to ground is what Aixun did and it ended up with the controller losing connection with the thermocouple when soldering something with ground connected (it can happen to have it in the way). When that happens the controller sees a momentary "low temperature" coming from the thermocouple and tries to compensate by sending full power to the tip. I showed my Aixun overshooting up to +160C on my tips. And that genuine JBC tip only lasted 12 months, wonder why... :( Maybe removing the ground connection is the "lessen of the two evils": you get 90V but - as you noticed - very little current so it's kind of "safe" for the components? After all that's how USB soldering irons work - they have a voltage and they are ungrounded. Call me old-fashioned but I'm happy with a soldering iron which is grounded and has no voltage at the tip :) Thanks for showing us the mod :)
I want to see the followup @Defpom to see if this is still holding up and to see if your iron tips are getting accurate temperature readings with this modification
If did not want to ground the tip, you could have used a capacitor. The voltage on the tip i expect is ac coupled to it so there will be no problem with decoupling it to earth. Any conductor floating around ac will get a voltage induced on it, current available will be based on impedance of the coupling. Magnetic or capacitive will not provide much to a floating conductor. Could be to reduce noise if they emc tested it😂
Ich habe das gleiche an meiner DWS 200 Festgestellt. Ich habe überlegt, die Erdung direkt zur Erde über eine Klemme (die in der Station eingebaut wird) und nicht über das (Netzkabel) T-Netz, wo der Schutzleiter einer Hausinstallation am ende auf dem Neutralleiter verbunden ist. Eine Externe Erdung ist in jedem Labor Pflicht. Deshalb habe Gute Lötstationen eine Klemme für die Kolbenetdung Vorgesehen.
Please do check what happenns if you now touch something earthed with the tip. Asking, because I've tried that after soldering a 0-ohm onto those pads, and afterwards it appeared to mess up temp sensin. The iron would start pumping significant heant into the tip while the temp indication seemed to sag somewhat - however, when the tip to earth contact ends, it then shows a significant temp overshoot, like 450C instead of the set 300C. And I'm affraid it could fry the heater in the tip, or something, if I'd held the tip on the earth for longer.
Now all you have to do is the same for the Sequre soldering tweezers. That too has the same problem due to the PSU not having an earth connection. One solution I have seen is to plug in a USB A cable into PSU and attach its 0v wire to earth.
I use Hakko soldering equipment and the tips are absolute direct earth grounded. No way should that have been left floating. Missing part was probably intended as a fast blow fuse in case the tip touches a live circuit, like a mains line or DC supply, that has earth ground reference. Good video!
They get those power supplies from other manufacturers and just plug them in. I heard that some soldering stations from china don't work properly if you ground the tip, probably there's some sensing circuitry in them that relies on a floating negative. I'm surprised this one works. I'm waiting for mine to arrive, and this is the first thing I'll do.
@@MadaraUCHIHA-hy9xe I haven’t used it much yet as I’ve spent most of my time recently writing code for someone’s website, working on this was actually the last electronics work I did !
@Defpom It would be good if you could do a short followup video or comment, letting us know what happens if you connect the tip to mains earth following your mod. Does it behave well or does it exhibit the same, pretty nasty, problems that tony359 had with his Aixun T3A? If it does work well it would be interesting to know how FNIRSI avoided it - beyond eliminating the ground connection altogether.
EMC problems? Maybe it failed an EMC test with the iron grounded as any HF leakage current from the switching PSU could be coupled back to the iron lead which would act as an additional antenna.
igual en la jbc esta conectado a tierra una resistencia de bajo valor + un fusible de 1.25 A y en paralelo al fusible una resistencia de 1 mega y no se pueden soldar circuitos con alimentacion en vivo el fusible saltara
I just received this station and it seems to have trouble melting solder even though I have it set to 450 degrees Celsius (way too high I know). I don't have a tool to calibrate it so should I just return the thing? Has anyone experienced anything like that before and have any tips? It seems like the tips temp fluctuates even though it does not show it on the display. I find I have to touch the solder near the upper sides of the tip as well which doesn't seem right. These are brand new tips and I have a lot of trouble getting it to work.
Now put a note on the unit. "Never work on a live voltage connected device " Imagine touching your "earth" solder pen on the hot side...😮 Even on the low side could be a problemow
Now you are not allowed to solder on board with live voltage. There are cases where you just do not or cannot eliminate voltage from the board you are soldering (machine has to keep running while you replace spare part). At least they left traces open, so you can do the mod and be responsible for it. Of course, there are pros and cons, sensitive electronic that is without voltage, now cannot be damaged with grounded tip.
I would have thought a y2 capacitor would be better? Could be right about the usbc need to test it you said the resistor as a fuse!!! you don't want it as a fuse that's defeating the point of having Earth! I would say something like a 200 300 ohm resistor or an induction coil 3 mH 1 mm gauge
J'ai vérifié le mien, j'ai un voltage qui varie 30 à 40 volts dépendant du voltemetre utiliser. D'après moi c'est un voltage induit par effet capacitif. (Varie en fonction de l'impédance du multimetre) C'est la raison pour laquelle qu'on lit un voltage AC et non DC En ajoutant une résistance de 5.58k en parallèle avec le multimetre,le voltage mesuré est de 0.470 volts.
when I measured with the multimeter I went from 40 volts to 0.470 volts. what confirms it for me is by capacitive effect. I did not modify the soldering station after this. resistance between soldering tip and ground > 2 G ohms at 250 volts.
*BAD MOVE!!!* (Part 1 of 2 in attempt to avoid YT deletion) The tip thermocouple is connected between the tip and heater element common. The latter will be connected via the iron's flex to the station's -ve. So you've just created an alternative return route for the heater current should you try to solder a joint that is mains grounded -through the thermocouple, tip, grounded equipment, mains earth, 2ohm resistor back to station supply -ve. A few amps of heater current going through your precious, pride and joy, device-under-repair might not make it betterer! Also bad, if not worse, the new 2ohm resistor + plus the parallel mains earth route are now shorting out the tip's thermocouple so the station will likely pump up the power to maximum!
Y que pasa si pones 0.22 ohm en lugar de 2 ohm que posee la jbc ( la jbc tiene 0.22 ohm mas un fusible de 1.5 amp.) conectado a tierra , funcionaria ???
@@orlandoalarcon4158 Maybe, but I doubt it. As far as I can remember (it was a year ago I looked at the JBC schematics), JBC ground the actual tip - not the TC/heater common lead/-ve power supply via the fuse + resistor. The fuse has a parallel 1.2MOhm resistor to keep it ESD safe should the fuse blow and the series resistor is only there, I believe, to allow them to measure any earth leakage current. You could do the same to the DWS-200 but the mains leakage current through the class Y EMI/filter cap in the SMPS would then flow through the TC (thermocouple) potentially swamping the tiny (uV) TC signal upsetting the tip's temperature regulation. The JBC station doesn't have that problem because it uses a mains transformer and thus does not need a class Y cap to filter high frequency switching noise.
Never ever connect a soldering tip to PE. Think what happens if you get in touch with something still powered. Guess why weller still uses legacy transformer PS in their WX Series. I own a WX2 and the tips are definitely not grounded. Nor are they grounded in my old Magnastat stations. This is not the right way to assure ESD protection.
This is total BS , I don't know any technician ever touch live unit with soldering iron! Potentials in some cases could be even worse as we seen. I have the same unit , but I'm still in investigation what is the proper way to solve this issue.
entonces jbc tampoco serviria si tiene conexion a tierra una resistencia de vajo valor + un fusible de 1.25A y dice que no se pueden soldar con circuitos alimentados caso contrario el fusible saltara
Finirsi seems to pride themselves in poorly designed and implemented products. . I avoid Finirsi like the plague. Good thing you weren't using it on ESD/Voltage sensitive components! Not sure why you would even risk having that c ... unit on the bench when you have a JBC!
"Ahh fucks sake" lol.. I feel that in my soul. That fact that you didn't edit that out got you my sub. :P
In some designs, the tip is deliberately isolated from the mains supply and the earth. This "double insulation" approach means that the user is less exposed to electric shocks and equipment failure, i.e. accidentally goes soldering a live board and BANG! The manufacturer is just hedging their bets! At least there's an option on the PCB though as maybe some countries demand it?
Very good comment imho. I'd say: Either ground it properly or build a floating power supply with reasonably low common mode noise. Or add a capacitor to ground or something. Can be done. Not a good comparison, but my trusty old Agilent E3632A linear bench supply measures ~2V AC/1uA... I guess it will be more difficult with a SMPS, generally speaking. I wouldn't feel comfortable using this station tbh.
Thanks for sharing this! On a side note: the Fluke 87v "LO" function is a low pass filter for weeding out higher freq noise from VFDs and inverters. Unfortunately, it doesn't have a "LoZ" function for low impedance.
Give that wee cat a cuddle 😀
Probably was intended to have a 1k PTC thermistor there, and it was cost cutted out. A 1k PTC will work well, low resistance, and limits current if you accidentally touch a voltage source, and the PTC side will also limit current as it heats up. A second 2k unit in parallel, with a small bridge and a red LED, will show if there is high voltage drop across the resistor, though not really needed.
That intro! sms, wifey, CAT. Everything at once 😂
Yep😅
I am not an expert on how the 245 works but I think wiring the negative to ground is what Aixun did and it ended up with the controller losing connection with the thermocouple when soldering something with ground connected (it can happen to have it in the way). When that happens the controller sees a momentary "low temperature" coming from the thermocouple and tries to compensate by sending full power to the tip. I showed my Aixun overshooting up to +160C on my tips. And that genuine JBC tip only lasted 12 months, wonder why... :(
Maybe removing the ground connection is the "lessen of the two evils": you get 90V but - as you noticed - very little current so it's kind of "safe" for the components? After all that's how USB soldering irons work - they have a voltage and they are ungrounded.
Call me old-fashioned but I'm happy with a soldering iron which is grounded and has no voltage at the tip :)
Thanks for showing us the mod :)
If you try to unsolder a charged capacitor now (e.g. 60V) what would happen?
It would discharge very rapidly…. Worst case the resistor would act like a fuse.
Depends on capacitance and which side desoldered first.
Scary what this😮 9:25 allows to be imported snowflake country
I want to see the followup @Defpom to see if this is still holding up and to see if your iron tips are getting accurate temperature readings with this modification
Tengo 2 preguntas???
Que pasa si No tengo POZO a tierra.
Y profe como obtuviste los voltajes y corrientes en la punta ,gracias.
what is the model of that tweezer soldering iron
@@thehitman5007 it’s the Sequre HT140, I reviewed it last week 👍
@TheDefpom i purchased the yihua 938d and it was absolute garbage. Wasted my money on it.
@ yeah I should probably take that video down, there are much better options now.
If did not want to ground the tip, you could have used a capacitor. The voltage on the tip i expect is ac coupled to it so there will be no problem with decoupling it to earth. Any conductor floating around ac will get a voltage induced on it, current available will be based on impedance of the coupling. Magnetic or capacitive will not provide much to a floating conductor.
Could be to reduce noise if they emc tested it😂
Just a thought! I wonder if it caused problems with the domestic RCD tripping?
Ich habe das gleiche an meiner DWS 200 Festgestellt. Ich habe überlegt, die Erdung direkt zur Erde über eine Klemme (die in der Station eingebaut wird) und nicht über das (Netzkabel) T-Netz, wo der Schutzleiter einer Hausinstallation am ende auf dem Neutralleiter verbunden ist. Eine Externe Erdung ist in jedem Labor Pflicht. Deshalb habe Gute Lötstationen eine Klemme für die Kolbenetdung Vorgesehen.
Please do check what happenns if you now touch something earthed with the tip. Asking, because I've tried that after soldering a 0-ohm onto those pads, and afterwards it appeared to mess up temp sensin. The iron would start pumping significant heant into the tip while the temp indication seemed to sag somewhat - however, when the tip to earth contact ends, it then shows a significant temp overshoot, like 450C instead of the set 300C. And I'm affraid it could fry the heater in the tip, or something, if I'd held the tip on the earth for longer.
You wouldn't get that problem with a y2 capacitor I don't believe
Now all you have to do is the same for the Sequre soldering tweezers. That too has the same problem due to the PSU not having an earth connection. One solution I have seen is to plug in a USB A cable into PSU and attach its 0v wire to earth.
Not an issue in my case, my USB=C supply is earthed, so the voltage on my tweezer is fine.
A little voltage never hurt anybody 😂
I use Hakko soldering equipment and the tips are absolute direct earth grounded. No way should that have been left floating. Missing part was probably intended as a fast blow fuse in case the tip touches a live circuit, like a mains line or DC supply, that has earth ground reference. Good video!
Have you checked for voltage on the tip of the soldering tweezer ?, Some usb power adapters can have the same voltage leakage
@@AndyDeay yes, only getting 1.9V as my usbc supply is earthed, most are not
What type of usb c supply do you have
They get those power supplies from other manufacturers and just plug them in. I heard that some soldering stations from china don't work properly if you ground the tip, probably there's some sensing circuitry in them that relies on a floating negative. I'm surprised this one works. I'm waiting for mine to arrive, and this is the first thing I'll do.
Que pasaria si pones un fusible ?
Un video de control de temperatura despues de madificacion profe
What was your experience with the station till now, especially with large ground traces?
@@MadaraUCHIHA-hy9xe I haven’t used it much yet as I’ve spent most of my time recently writing code for someone’s website, working on this was actually the last electronics work I did !
@@TheDefpomdidn’t know you are coder too
its safe with that resistor to update firmware via USB-C ?
@@Rudimaximus that is the question, it probably depends on how your computer handles earth connections on its ports.
@Defpom It would be good if you could do a short followup video or comment, letting us know what happens if you connect the tip to mains earth following your mod. Does it behave well or does it exhibit the same, pretty nasty, problems that tony359 had with his Aixun T3A? If it does work well it would be interesting to know how FNIRSI avoided it - beyond eliminating the ground connection altogether.
@@tonyh6309 it’s been working fine.
EMC problems? Maybe it failed an EMC test with the iron grounded as any HF leakage current from the switching PSU could be coupled back to the iron lead which would act as an additional antenna.
igual en la jbc esta conectado a tierra una resistencia de bajo valor + un fusible de 1.25 A y en paralelo al fusible una resistencia de 1 mega y no se pueden soldar circuitos con alimentacion en vivo el fusible saltara
I suspect a bi-directional avalanche TVS diode is the right component for the missing position.
I just received this station and it seems to have trouble melting solder even though I have it set to 450 degrees Celsius (way too high I know). I don't have a tool to calibrate it so should I just return the thing? Has anyone experienced anything like that before and have any tips?
It seems like the tips temp fluctuates even though it does not show it on the display. I find I have to touch the solder near the upper sides of the tip as well which doesn't seem right. These are brand new tips and I have a lot of trouble getting it to work.
sounds like you should send it back.
i received this station today and i dont have problems to metling solder with 300 degrees, maybe you need to calibrate it.
Now put a note on the unit. "Never work on a live voltage connected device "
Imagine touching your "earth" solder pen on the hot side...😮
Even on the low side could be a problemow
@@MiguelHernandez-ef3pw I would never work on live equipment anyway, that is just asking for trouble, is a great way of killing yourself.
en jbc tambien debes poner esa NOTA pues esta conectado a tierra con una resistencia de vajo valor
China doesn't seem to care much about grounds. That's my experience with most devices I've gotten from there.
I trust Pace, Hakko, and maybe Weller. These no-name ultra-cheap Chinese stations have no place on my benches.
Now you are not allowed to solder on board with live voltage. There are cases where you just do not or cannot eliminate voltage from the board you are soldering (machine has to keep running while you replace spare part). At least they left traces open, so you can do the mod and be responsible for it.
Of course, there are pros and cons, sensitive electronic that is without voltage, now cannot be damaged with grounded tip.
This is not a unit I would buy.
I would have thought a y2 capacitor would be better? Could be right about the usbc need to test it
you said the resistor as a fuse!!! you don't want it as a fuse that's defeating the point of having Earth! I would say something like a 200 300 ohm resistor or an induction coil 3 mH 1 mm gauge
It should be MOV between earth and GND common.
J'ai vérifié le mien, j'ai un voltage qui varie 30 à 40 volts dépendant du voltemetre utiliser.
D'après moi c'est un voltage induit par effet capacitif. (Varie en fonction de l'impédance du multimetre)
C'est la raison pour laquelle qu'on lit un voltage AC et non DC
En ajoutant une résistance de 5.58k en parallèle avec le multimetre,le voltage mesuré est de 0.470 volts.
Can you let us all know how you went with that resistor in there please
when I measured with the multimeter I went from 40 volts to 0.470 volts. what confirms it for me is by capacitive effect. I did not modify the soldering station after this.
resistance between soldering tip and ground > 2 G ohms at 250 volts.
*BAD MOVE!!!* (Part 1 of 2 in attempt to avoid YT deletion)
The tip thermocouple is connected between the tip and heater element common. The latter will be connected via the iron's flex to the station's -ve.
So you've just created an alternative return route for the heater current should you try to solder a joint that is mains grounded -through the thermocouple, tip, grounded equipment, mains earth, 2ohm resistor back to station supply -ve. A few amps of heater current going through your precious, pride and joy, device-under-repair might not make it betterer!
Also bad, if not worse, the new 2ohm resistor + plus the parallel mains earth route are now shorting out the tip's thermocouple so the station will likely pump up the power to maximum!
Y que pasa si pones 0.22 ohm en lugar de 2 ohm que posee la jbc ( la jbc tiene 0.22 ohm mas un fusible de 1.5 amp.) conectado a tierra , funcionaria ???
@@orlandoalarcon4158 Maybe, but I doubt it. As far as I can remember (it was a year ago I looked at the JBC schematics), JBC ground the actual tip - not the TC/heater common lead/-ve power supply via the fuse + resistor. The fuse has a parallel 1.2MOhm resistor to keep it ESD safe should the fuse blow and the series resistor is only there, I believe, to allow them to measure any earth leakage current.
You could do the same to the DWS-200 but the mains leakage current through the class Y EMI/filter cap in the SMPS would then flow through the TC (thermocouple) potentially swamping the tiny (uV) TC signal upsetting the tip's temperature regulation. The JBC station doesn't have that problem because it uses a mains transformer and thus does not need a class Y cap to filter high frequency switching noise.
Never ever connect a soldering tip to PE. Think what happens if you get in touch with something still powered. Guess why weller still uses legacy transformer PS in their WX Series. I own a WX2 and the tips are definitely not grounded. Nor are they grounded in my old Magnastat stations. This is not the right way to assure ESD protection.
This is total BS , I don't know any technician ever touch live unit with soldering iron! Potentials in some cases could be even worse as we seen. I have the same unit , but I'm still in investigation what is the proper way to solve this issue.
entonces jbc tampoco serviria si tiene conexion a tierra una resistencia de vajo valor + un fusible de 1.25A y dice que no se pueden soldar con circuitos alimentados caso contrario el fusible saltara
Wouldn’t use that on my bench fire hazzard
Finirsi seems to pride themselves in poorly designed and implemented products. . I avoid Finirsi like the plague. Good thing you weren't using it on ESD/Voltage sensitive components! Not sure why you would even risk having that c ... unit on the bench when you have a JBC!