Aixun T3A overshooting?

[CapLeaker]

Re: Aixun T3A overshooting?

Is the device you solder on connected to power mains? Other than that it doesn’t make any sense what your saying. None of my soldering irons do that.

[tony359]

Re: Aixun T3A overshooting?

Thanks.

no power, just ground. No batteries on the board.

And if someone said "disconnect it from ground" then my question is "so the T3A won't work when I am pre-heating a board as the pre-heater is grounded".

Do you have a T3A as well?

[harp]

Re: Aixun T3A overshooting?

Please do some measurement, voltage and current (carefully) accross your ground clip and soldering tip, both ac and dc?

Also check voltage of your ground clip against mains socket, with one pin should be 240v and with another 0.0v (earthed from distributor)

[tony359]

Re: Aixun T3A overshooting?

Here are the measurements

GND to TIP resistance is 0.7Ohm when the station is off (my leads read 0.4 Ohm when shorted).

If I take the tip to 100C and then ask the station to go to 400C - so the tip is heated constantly for a few seconds - during that time my Fluke measures OL.

When the tip keeps the temperature steady, resistance jumps around, clearly when the tip is being heated continuity to ground is lost??

VOLTAGE

GND to TIP: 0.584V AC when heating (same trick than before)
GND to TIP: 0.915V DC when heating (same trick than before)

CURRENT
GND to TIP: 1.5A DC when heating (same trick than before)
GND to TIP: 1.74A AC when heating (same trick than before)

MAINS check
The chassis is indeed grounded and the GND clip too.

station GND to Mains GND: I do have continuity
Station GND to Mains: 0.26AC on one mains leg and 242VAC on the other.

I'm not sure I should read that amount of voltage and current on a soldering iron to be honest. My older iron doesn't read anything like that, it reads 0V at all times.

[harp]

Re: Aixun T3A overshooting?

Station GND to Mains: 0.26AC on one mains leg

Ground clip is mounted on station gnd? (that black aligator ground clip that you show on video)
I ask because it is possible that ground clip have loose resistive conection with wire - ground clip must be 0.0Vac to earth ground, otherwise it is not well grounded.

The measure is very suspicious, its look like major leaking, and I am not expert to give value conclusion, but yout tip may damaged some sensitive devices, maybe is best to do not use that soldering station till somebody with identical model compare and confirm measure reading...

[tony359]

Re: Aixun T3A overshooting?

Yes ground clip is mounted on the station. I used that for my measurements as I read 0.7Ohm with mains ground so it does seem to be a direct connection.

I thought the same, that station would be able to damage some sensitive stuff.

I hope someone can help me, I have to get back to the seller tomorrow though to report the issue. I'll make a video explanation and let's hope they don't BS me or offer a partial refund...

[CapLeaker]

Re: Aixun T3A overshooting?

Thanks.

no power, just ground. No batteries on the board.

And if someone said "disconnect it from ground" then my question is "so the T3A won't work when I am pre-heating a board as the pre-heater is grounded".

Do you have a T3A as well?

Yes, I do have the T3A and run the T245 and the T12 pens and elements. I can solder copper pipe, or something that has a ridiculous heat sink on it with my T245 no problem.

Look for something copper that is bigger like a copper pipe / sheet and see if you can solder to that.

When I saw your video, it seems like each time the T3A heated the pad a bit harder, I could see the T3A ramping up heat fast and in the peaks is seems to go “crazy”. Yours does it every time the power demand from the pen is high. Check it out and see if you can verify this.

[tony359]

Re: Aixun T3A overshooting?

Look for something copper that is bigger like a copper pipe / sheet and see if you can solder to that.

.

I believe you might be suggesting that the issue happens when the PSU is being driven harder.

I can assure you this is not the issue. On the latest video I am barely touching a small solder joint - it doesn't melt as there is no flux and it's oxidised - and it misbehaves immediately. The spike you see on power is caused by the issue and not vice versa. The very same solder joint doesn't trigger the issue when the PCB is not grounded.

https://www.youtube.com/watch?v=8OXDOZTy7t0

Anyways, yes I did try the 5p copper coin test. I've melted 10cm of solder on a 5p coin and waited until it flows on the whole coin. It takes 40 seconds while with my old station it takes 100 seconds. That's why I really like the T245!

But I am pretty confident it's not the PSU.

It sounds like you've never experienced this issue yourself - would you think you're soldering on grounded PCBs sometimes? Again, it's not touching ground itself which causes havoc.

Thanks for now!

[harp]

Re: Aixun T3A overshooting?

Yes ground clip is mounted on the station. I used that for my measurements as I read 0.7Ohm with mains ground so it does seem to be a direct connection.

This is not solve your problem, but be aware of chinese creativity - they may using a aluminium or ferrous wire instead of copper, and to do so is offen only plated with copper to look like copper wire... the wire have noticable resistance (about you measured) and heating while carry more amps (car bulb etc). Also, they regulary ommit soldering wire to aligator clamp, and contact is not reliable, like to coroded due to difference in material potencial...

On pictures is wire that hang on regular magnet - this is my test and later I do a label of this wire with "Fe".

[tony359]

Re: Aixun T3A overshooting?

thank you - I am aware that by buying on Aliexpress it's a shot in the dark.

Just so that I understand correctly, what you point out is not relevant to the issue I am experiencing, just a general comment, am I correct?

[harp]

Re: Aixun T3A overshooting?

Yes, general comment.

[CapLeaker]

Re: Aixun T3A overshooting?

Ahh! Now I get it! I don’t use the ground wire! I don’t ground to the device I work on to the soldering station ever. What pencil station do you have? I have the fancy one where the tip turns off when the pencil is resting in the holder.

[CapLeaker]

Re: Aixun T3A overshooting?

That ground I thing is either to go to ESD device or to a docking station. Not to ground your PCB with

[tony359]

Re: Aixun T3A overshooting?

Ok but that was only an example, ignore that it comes from the station and imagine it comes from the mains socket, the result is the same.

Scenario 1: My motherboard is on a GROUNDED preheating station. I cannot un-ground it!
The motherboard will inevitably touch the pre-heater hence the motherboard is grounded.

In that scenario, I see the issue you see in the video. This is how I discovered it. I was soldering on a pre-heater.

We also have the 1V 1.5A at the tip which is concerning, IMHO.

Can I possibly be the only one on the planet noticing this "design feature" with this very well reviewed station?

[CapLeaker]

Re: Aixun T3A overshooting?

I am going to try that with my solder station tomorrow and see what happens, if I can find a plug to fit that jack in the back.

I don’t have a pre-heater, just use the brute force of the T245.
If memory serves me right there are ungrounded pencils for it too.
Very interesting feature, for sure. My Weller WD-1 has a transformer inside.

[tony359]

Re: Aixun T3A overshooting?

The crocodile lead came with the station so you might have it somewhere - and thanks for testing for me!

Pre-heating is mostly for BGA rework - I wish the T245 could do that

Once a BGA chip is pulled I need to clean the pads. The board is still going to be on a pre-heater at that stage. And at that point I would be concerned about injecting 1V into components which might not like 1V at 1.5A to be honest.

Anyways the pre-heater is an example. I'm sure there are tons of situations where you might have ground connected to the item you are soldering.

And again the measured voltage is a concern IMHO.

thanks again!

[stj]

Re: Aixun T3A overshooting?

so this is related to the sleep-function?
can it be disabled in the menu's?

[tony359]

Re: Aixun T3A overshooting?

sleep function?

What did I miss? Are you suggesting it could be related to the sleep function?

[tony359]

Re: Aixun T3A overshooting?

little update: I tried FW 1.34 and... well the "NO TOOLS" error is not there anymore but I can see the power jumping 0-100% most of the time on those "affected" joints. The display keeps saying 350C but if I quickly measure the tip it's at 450C. +100C overshoot.

I feel this is a design flaw they're trying to hide by software.

And yes, the handle is making a much quieter buzzing noise with 1.34.

I really can't believe I'm the only one reporting this online.

[stj]

Re: Aixun T3A overshooting?

so the buzzing is the tip/cartridge, not the base?