Aixun T3A overshooting?

[tony359]

Re: Aixun T3A overshooting?

yes it's coming from the handle.

This is the video I have sent Aixun for review.

https://youtu.be/KzfpZB6R6js

That said, @Capleaker, I won't be able to go back to my standard iron. For fun I tried de-soldering a power connector from an XBOX 360 board. Half of the pins were the shell of the connector itself. It's taken a while, with braid, but I did it and didn't damage anything. Impressive.

[CapLeaker]

Re: Aixun T3A overshooting?

I think your T3A is faulty.
Indeed there was a cable that came with it, just mine has banana plugs on both sides. I plugged that in, put a crocodile clip to it and grounded out the outside of a USB port, then started solder around on the case and everywhere else, no problem. Grounded out an old VHF tranceiver and I solder around like nobody’s business. I did exactly that what you did in the YouTube video. My T3A works just fine, as it supposed to. My T245 pencil does not hum and that ground point on the back of the T3A is connected to the earth pin on the AC cable. I measured abou 0.05VDC between the hot tip and that ground point.
So yours must have “special features”. Lol

[tony359]

Re: Aixun T3A overshooting?

well that's great news I guess! What FW are you on?

Let's hope Aixun replies with something helpful!

Really appreciated the time you spent on doing this test for me!

[CapLeaker]

Re: Aixun T3A overshooting?

Running firmware 1.26

[tony359]

Re: Aixun T3A overshooting?

Maybe I should try that LOL!

[CapLeaker]

Re: Aixun T3A overshooting?

Nah, it’s something electrical related, not firmware based. That’s what I think anyway.

I did buy mine from Aixun official store through Ali.

[tony359]

Re: Aixun T3A overshooting?

I didn't know Aixun had an official store but I bought it from a recommended store based on SDG Electronics review. So finger crossed.

1.34 behaves differently than 1.33. On 1.33 I have "no tools" when the "fault" shows up. On 1.34, the power jumps 0-100% until I remove the tip and by that time the overshoot is +120C.

Slightly off topic, what is an alternative for a T245 station without spending an arm and a leg?

[CapLeaker]

Re: Aixun T3A overshooting?

The Aixun was the best bang for the buck when I researched and ordered mine. I am so happy with mine, I even got the T12 pencil and elements. Wouldn’t consider trading it.

[tony359]

Re: Aixun T3A overshooting?

Ok, then I hope mine is defective!

[tony359]

Re: Aixun T3A overshooting?

Aixun asked me to contact their support team directly at this address? https://www.jcprogrammer.com/

Who is making those stations in the end?

[tony359]

Re: Aixun T3A overshooting?

I've now found others reporting the same issue I am reporting. As speculated, it sounds like it's something to do on how the station is measuring the temperature. I'm yet to get a feedback from Aixun but the fact that others are seeing the same probably means it's "normal".

I guess the vast majority of people won't use a pre-heater or solder on grounded equipment.

[CapLeaker]

Re: Aixun T3A overshooting?

Can’t be. Why doesn’t mine have your symptoms? If you don’t mind, in what countries are the others? Does it have to do using 220 vs 110V?

[tony359]

Re: Aixun T3A overshooting?

It really needs a specific PCB and specific pins. Could it be that you didn’t stumble into that? On the mobo I was soldering only 4-5 pins of an ISA connector were showing the issue.

I’m 220V, UK. Not sure about the others.

[harp]

Re: Aixun T3A overshooting?

Nobody concerned about 1.5A - 1.74A...?

[tony359]

Re: Aixun T3A overshooting?

I am.

But as you noticed nobody else seems to be so I’m not sure what to think ��

[redwire]

Re: Aixun T3A overshooting?

What is happening is the thermocouple op-amp is picking up noise due to the ground loop from touching the tip to something earth-grounded.
Usually this noise is from the SMPS, high frequency say 66kHz.
You could prove it by taking a say 10nF cap one leg to earth ground, and touch the tip to the other leg. If it freaks out then that is the problem.

There's a few ways to fix it.

[CapLeaker]

Re: Aixun T3A overshooting?

I don’t understand why some units have that problem, while others not. I only had 0.05VDC measured coming out of my tip to earth ground. Could the problem be the T245 element itself? How else would voltage to be able to get on the tip?

Yours definitely went crazy if you used that earth pin. Mine absolutely does not care if the earth ground touches the soldering tip. I’ve tried a few times now hooking the earth ground to everything I repaired.

I fixed a HDMI port on a PS5 today and used the earth ground. No problem. Voltage between the tip and earth ground was again 0.05V. Yesterday, I fixed a PA phone Paging speaker and a Motorola CDM1250 VHF. No problem then either. What gives?

[redwire]

Re: Aixun T3A overshooting?

They're trying to fix the hardware issue with software. What F/W rev are you running?
You have a lot of noise on the temperature signal, you can only take a temp reading when the heater is off due to voltage drops in the wiring.
If you are skilled at writing real-time code, you can read the sensor and filter out noise before going into the PID routine. But... the firmware is not any good at that yet.

Is the tip connected to PE? Or is it floating?

Another issue I have seen is the SMPS transformer wound by some villagers end up really noisy with the primary coupling too much noise to the secondary. Or the SMPS is not stable.
Also the thermocouple op-amp can vary widely in quality. That was the cause of many problems with bad temp readings.

[tony359]

Re: Aixun T3A overshooting?

I don't understand why some units have that problem, while others not. I only had 0.05VDC measured coming out of my tip to earth ground. Could the problem be the T245 element itself? How else would voltage to be able to get on the tip?

I see you are using the station extensively so I don't mean to patronise you here, just clarifying things.

Voltage is only measured when the tip is actively heating. If I measure when it's keeping a stable voltage, I'd probably get the same reading.

To reproduce what I did, set one pre-set to 400C, then cool down the tip to 100C, then place your meter on the tip (not in auto mode, it won't be fast enough, I selected an appropriate range on my Fluke and set the Fluke to display the maximum reading).

Now the tip is 100C, select the 400C channel. The tip will be constantly heated for 3-4 seconds and then is where I measure the voltages I reported.

Yours definitely went crazy if you used that earth pin. Mine absolutely does not care if the earth ground touches the soldering tip. I've tried a few times now hooking the earth ground to everything I repaired.

I fixed a HDMI port on a PS5 today and used the earth ground. No problem. Voltage between the tip and earth ground was again 0.05V. Yesterday, I fixed a PA phone Paging speaker and a Motorola CDM1250 VHF. No problem then either. What gives?

Again, just a clarification: not an earth pin. Nothing happens if I touch an earth pin. It's "some" pins on a grounded PCB.

I don't know what to say though. I had that issue 10 minutes into using the station. 3-4 pins of each ISA slot would show the issue.
Then I was practicing on an XBOX on a pre-heater and the USB connector was buzzing loudly when touching the pre-heater itself.

What I am trying to say is that it feels like an obvious behaviour to me, I didn't do anything so special to see that.

They're trying to fix the hardware issue with software. What F/W rev are you running?

I agree with that.

I tried 1.34 and 1.33. 1.33 is "louder" but at least keeps the temperatures where they are supposed to be. Also 1.34 doesn't show "NO TOOL" when the issue happens but the power level goes 0-100 like crazy until the tip is on the affected pin.

Is the tip connected to PE? Or is it floating?

I read full continuity to ground but only when not heating. It could be because my Fluke won't like sensing voltage when in continuity mode though.

You could prove it by taking a say 10nF cap one leg to earth ground, and touch the tip to the other leg. If it freaks out then that is the problem.

Will try that thanks!

[CapLeaker]

Re: Aixun T3A overshooting?

Ok, redone the voltage measurement as you suggested, but at 0.5V I am still nowhere near the 1.5V. What elements did you get? Mine are made by Aixun with the black rings. Maybe there are low quality elements that are the problem? Dunno… I give up, as I can’t replicate the crazy behaviour of your station no matter what I try.