Any opinions on the AiXun T3A?

[GnomeZA]

Use atx psu. Separate 5v and 12v.
https://www.eevblog.com/forum/reviews/new-aixun-t320-any-opinions-on-it-(with-inside-pics)/msg5302402/#msg5302402

If what Gnomeza say is true, then perhaps it is possible to modify cheaper mechanic c211 which have 24v transformer and use buck converter 12v.

Both ATX PSU and a buck converter is not isolated.  They are referenced to the same supply.  Current can flow from the 12v to 24v supply and ditto for ATX supplies, it is a common hack to use 12v as your positive and 5v as your negative for a 7v supply using an ATX supply.

But actually aixun t420d use different winding for heating element. And the controller use 15v winding. (Based on Steve video)

That is what I said.  They are isolated supplies.  Meaning they are not referenced to each other.  There is no current that can flow between those two supplies.  JBC also has galvanically isolated supplies for their control and heater.

[GnomeZA]

Good to hear the 420D behaves ok when ground is involved.

SDG said he tested it too and found no reference such behaviour.  In another post somewhere.  So at least we have a trusted public figure saying the same thing

Too bad the issues I highlighted were not public before I purchased mine - or at least I didn't find anything online when I looked. A T3A without the voltage leak and grounding issue would be a nice one.

I said this as a comment on your video also.  I would do exactly what you had done if it were my profession.  I'm a hobbyist, if I can't solder this weekend or whatever
But if it is my job, I wouldn't have risked it and bought a JBC station.
I honestly think you made the right call.

Even with me or SDG or "..." saying, well I think T420D is ok.
There isn't years of testing, it has been like, what? two weeks.
That is still a huge risk for you to take.

Do you think there is a way to develop a similar station with an SMPS supply without those issues? Just curious.

I've avoided commenting on this because I think I have some ideas to get past it.
But I wanted to test it on the T3A.

My hesitation is that Aixun actually do make really decent designs, they aren't stupid.
So there must be a reason they are using these hacks to get around this, even in the T320.

Instead of say two isolated windings on the SMPS not referenced to each other or isolated DC->DC converter (for logic control or thermocouple ADC).  Leading me to think I'm overlooking something obvious.

[tony359]

Even with me or SDG or "..." saying, well I think T420D is ok.
There isn't years of testing, it has been like, what? two weeks.
That is still a huge risk for you to take.

Well... it's a soldering station. A rod gets hot. The end.

What I am trying to say is that I still feel that £500 for a soldering station is too much for what it does.

My hesitation is that Aixun actually do make really decent designs, they aren't stupid.

You might be overestimating them

[Duglum]

On a kinda related topic.. did anyone try the AiXun C245 tips? They are producing a small range now and not only those useless two ultra-fine plus knife tip every chinese manufacturer seems to love.

https://www.aixuntech.com/product/c245-soldering-iron-tips-/

I found them on Aliexpress for around 7,60€ including VAT (plus 3-4€ shipping) which makes them about 25% of the price and really affordable compared to the ~30€ (plus 5€ shipping) genuine JBC tips go for.
But i understand that most other 3rd party tips have been more or less crap so far.. sooo the question is, are these any better?
JCID/AiXun at least seem to really want to get a foot into this market long-term with all these stations, constant firmware updates and now tips plopping up. Wonder how the T413 will turn out. 

[tony359]

Yes.

https://www.eevblog.com/forum/reviews/why-you-dont-want-to-buy-aixun-t245-tips

The "constant firmware update" is debatable. It's a soldering station. It shouldn't need so many updates. And most of the recent ones are to hide/mitigate hardware design flaws so be careful what you wish for

[GnomeZA]

The "constant firmware update" is debatable. It's a soldering station. It shouldn't need so many updates. And most of the recent ones are to hide/mitigate hardware design flaws so be careful what you wish for

The latest T420D firmware allowed me to turn off "temperature compensation" which I can only assume is the thing where they overshoot.
They also dropped the silly words like "dormancy" instead for English words people would actually deem appropriate for the situation.  Think it is "sleep" now.
There were also more configuration options around keeping the iron semi warm in the cradle and so on.
So for the T420D I think a lot of the updates are making the product better.

Covering up for hardware design problems might well be a problem for T3A at this point.
I'm not saying there are no bugs in T420D, but I think a lot of the firmware changes they made I really like, to the point that I'm not too eager to downgrade.

If only to never to see the word "dormancy" again.

[tony359]

I'm not against updates but, again, it's a soldering iron It really shouldn't need so many updates. If that happens, it means they didn't a good job in the start - see the translation mistakes and a feature which allows the tip to overshoot? Why would that be something you want to enable at all?

It's like they somehow managed to resolve the voltage leak on the T3A but instead of just fixing it they added a menu "Voltage leak and 160C overshoot: ENABLE/DISABLE"  

Anyways I see what you mean, they could just drop it and move to the next product.

[Paul_txl]

Hi,
I ordered a T3a a while back but haven't received it yet, I've also got a JBC T254 handle and bits. Unfortunately I read this thread too late but have been following it. Has anyone tried the new software options to see if they do actually cure anything?
I was also wondering if the problems with earthed workpieces exist with the T12 or 936 handles as I will be using those?
From what I can see the T3a drives these in a more orthodox manner due to the integrated thermocouple.
Also does the latest software still discriminate (if thats not too strong) against JBC tips or has that gone away? Hopefully I can answer these myself in a few weeks when the unit turns up.
Thanks for all the info,
Paul

[tony359]

I doubt any firmware could cure an hardware issue. An update might mitigate it at best - and apparently they also decided to go for the "hiding" option.

I'm not familiar with the T12 or 936 but I guess they all have thermocouples inside?

The problem with the T3A is that under some specific circumstances the signal coming back from the sensor becomes incorrect. The logic can only try to detect when that happens and stop pushing power into the tip like there is no tomorrow. But it won't be able to accurately control the temperature. It's like if someone covered your eyes while you're driving - you can only keep driving straight hoping there isn't a bend coming. You can get better glasses but they won't make things better when you cannot see

Happy to be mistaken of course!

[Paul_txl]

Thanks for the info Tony, I realise you've probably committed your t3a to the dustbin now. I think there has been some investigation into the cause of this  further up this thread, but it didn't seem conclusive. AFAIK the T12/936 have thermocouples in series with the heater normally, so would be generally be driven in a similar to the T3a, although there seem to separate connections on some "936" handles. I'd be happy to use it with the workpiece on a dissipative mat or connected through a resistor to ground if that prevents the problem but its a nuisance if the board is still in the chassis.

[c0d3z3r0]

Updating without vendor software is now possible: https://github.com/c0d3z3r0/aixun_t3x_updater

[c0d3z3r0]

... and finally we got the T3B bootloader: https://github.com/c0d3z3r0/aixun_t3a_rev/blob/master/bin/t3b_boot_v0.04.bin
Many thanks @ruslan_nesterenko