Quecoo T12-958 soldering station - INVER error?

[redwire]

I can see a few mistakes in your posted schematic. For alternate firmware like David's you need the I/O pin assignments.
What's interesting is Quicko is also monitoring heater current, this is not done anywhere else.
I've drawn a bunch of detailed KSGER T12 controller schematics. I quit after people took my schematics made a few edits and plastered their name all over it, for fame and glory.

[spleenharvester]

lol I tore the display ribbon and lack the dexterity to replace it. Just less of a pain in the ass to buy a new one.

I finished tracing the board - have attached the schematic if anyone is curious!

[stj]

there isnt much to kill - fix it

[spleenharvester]

Hi all

Long story short I tried to flash CFW and bricked it - turns out this is a brand new T12-958 board design with different pins, and until a few days ago the original firmware dump was unavailable. Myself and someone else over EEVBlog traced the pins and got a relatively complete schematic of the controller, and David kindly released a new CFW for it that I'm told is working. But I accidentally killed my T12-958 in the process of tracing the schematic so that's the end of that!

Quicko have actually released a 'T12-A' station that is designed specifically for Milwaukee/DeWalt/etc batteries recently - I might buy that as it's better suited to what I'm doing anyway, and see if they've done anything different to make it work with tool batteries. Would also be good to see how it compares to the new T12-958 board as it looks like they are possibly the same or very similar.

Cheers

[redwire]

It's puzzling. I can't tell if it's a hardware or firmware problem. Doubt it's the ground- the mains cord PE goes to the chassis and to the 24V(-)? Other brands float the entire 24VDC side, heater+tip included, which is a disaster for noise and HV potential when running off mains. Just wondering how TC noise could be worse running off a battery, isolated from everything.

[spleenharvester]

Yep INVERT on battery power with cold heater cart below about 100C. The temp is increasing as normal before the error so unless something is happening in a split second I think we can rule that one out.

I'm going to try the cap thing and if that doesn't work I'm going to flash with custom firmware, will update

[redwire]

Also note the battery jack input has two SS26 Schottky diodes 2A each for reverse-polarity protection. Hopefully they can take the current but I would check their voltage drop.

Just to be clear - it gives INVER error message on battery-pack power, with cold heater cart below 70-80C?

I thought the INVER error happens when the TC signal appears INVERTED, tip temp looks like it's dropping despite the heater being on. Backwards-wired thermocouples act like this.
Or the op-amp is unstable and flipping out, not so rail-rail as advertised lol. Picking up PWM noise is common especially on Aixun T3A etc.

I think you have a bad connection to the heater somewhere but why it shows up on battery power, I can't guess. Doesn't make sense.

[stj]

well the iron will peak just below 4A so that fine

[spleenharvester]

Cool thanks I'll give that a go.

Yeah first thing I did was bin that power switch lol. I replaced it with a metal DC jack, torpedo switch (one of the decent ones with screw terminals) and 14AWG wires. I think lowest rating in there is 10A max but better than it was at least.

[stj]

a low impedence cap - maybe 1000uf 35v FR series.
right across the battery terminals on the board.

if your battery pack can give 30A then the weak point is probably the connection terminals
as for Amazon - soon as it's mentioned i have to check what shit they are miss-selling!
that round power switch is rated for 12A resistive or 4A inductive load - NOT 30A
i have one in my hand right now!

[spleenharvester]

It's interesting this battery can run a 700W hoover no problem but struggles with this. I don't really understand enough about it I think. Quecoo have concurred it's something to do with the battery and someone elsewhere thought the [INVERT] error might mean it thinks it's not getting enough power from the AC/DC converter, which makes sense considering it won't know which one it is running from.

What cap do I need/whereabouts do I need to put it? Battery is wired to it with 14AWG wires. I wonder it is worth putting one inside the battery adapter casing so that it's already charged before plugging in. I use this adapter, modified with a female DC jack.

[stj]

the iron heater is pulsed and it's gonna peak at about 75w
so you need a good electrolytic cap at the board, and decent wires to the battery to avoid dips

[spleenharvester]

Thanks both, that's good to know,

With the Einhell battery the power is a stable +20.9V sagging slightly to +20.1V under load. The DC adapter behaves similarly. Neither is tripping the low voltage cutoff which is set at +19V.

Quecoo do a version that fits Worx, DeWalt, Makita, Milwaukee and Devon batteries, so presumably it is possible to tool battery power them (granted no one has done a teardown of these yet): https://www.quecoo.com/products/t12-...42322818793612

I had presumed they didn't do an Einhell version as it wasn't a significant enough brand, but maybe the power from Einhell batteries is too dirty or something? Is there anything else you can think of worth trying?

Worst case I might buy one of those battery powered ones and a few Milwaukee batteries, it's just more convenient for me to use Einhell because all of my other tools are Einhell. Tbf it would interesting to do a teardown and compare it to the T12-958 to see if they've done anything 'extra' to clean up the battery power.

[redwire]

You know, I don't see anything to change!
That looks like a Quicko STM32 T12 controller, they have better hardware design than KSGER. Not afraid to have a few extra parts and beefier mosfet etc.
The thermocouple op-amp is a 3-Peak TP1541A smt marking 541. I see they already have the 106 resistor pull-up I've been talking about.

Also, the PSU has the 24V battery input and so the 680uF caps are in-circuit then and no need for extra capacitors. There should be a menu to set the low voltage cutoff to say 18V.

That leaves your troubles to the cartridges or maybe the grounding but I can 't see a reason for battery operation to make the unit malfunction so.

[sam_sam_sam]

You do have to use a 24 volt battery pack you can not use a 18 volt battery pack it gives weird issues I know because I have tried it and I can tell it will work on a 24 volt battery pack

They also have a version that is battery powered with a BMS board but the BMS board has some strange issues with charging the battery cells even if the battery cells are closely matched I talking about no more than 50 milliamperes difference in milliampere hours which to this BMS board is not close enough for it to completely charge the battery pack this is unacceptable performance so I do not use it I have use a battery pack from Lowe’s brand power tool and converted a charger base to house the soldering controller board it works pretty good for my use

[spleenharvester]

Gotcha thanks that makes sense, I'll stick a 1M resistor on T+ to VCC, and a 100uF between VCC and GND. Is a 1/4W resistor sufficient in the former?

My T12-958 has no version marking on the PCB but reports HW version 3.20 and SW version 3.2S. I've attached some pictures for anyone else who stumbles upon this thread. The only modification done to this unit is moving the green earth wire from the connector (where it didn't actually connect to anything) to the GND pin of the GX12 connector (under the hot glue I added), everything else is stock. There are two 680uF 35V caps and a choke on VCC regardless of whether on AC or DC. On the AC side there's a 400V 33uF cap and a 22uF 50V cap.

[redwire]

I don't know exactly what your controller looks like. Quicko has 4 or 5 wire models. I have a Ver3.3 STM32 pic and sch I worked with a Russian fellow on it.
First add 1MEG resistor from GX12 pin 5 (T+) to +24V (VCC). It is so a floating op-amp does not pick up as much noise if the heater cart goes open--circuit.
The 24V bulk cap depends on the controller board regulator circuit and how stable power is on the battery. The mains PSU usually has two 1,000uF caps - you have one 680uF?
Point is, off the battery you have none of that so I suggest 47-100uF 35V added but not mandatory unless more is known about ctrl board.

[spleenharvester]

Just add a 1MEG pullup at the GX12 pin 5/heater/thermocouple input, to power +24V. It ends up being across the mosfet D-S. This stops the spazzing and freaking out, an open cartridge will now give a stable OPEN error message instead of picking up hum and noise. This is also aggravated by how noisy your PSU is. Your battery does float from PE ground so hum and noise pickup at the tip will be greater. Or add more bulk capacitance to the 24V rail, some controller boards are really cheap and have no 100uF cap there.

The tips have bad connections inside, new ones they sometimes need to be cooked it can sorta work. I think it's just dirty spot welds inside the white caps or in the maybe in the heating element, but using it seems to eventually fix the bad connection.
Some cartridges I have taken apart (caps) and tried to solder that bad connection to stop the drama.

There are also lots of other fixes to T12 quirks.

Thanks, this sounds promising. I'm struggling to figure out which pin that is on my GX12 connector you're referring to - I have T+, T-, GND, NTC, and SLP, is it one of those?

There's no 100uF cap on the controller board or on the power side, only one 680uF cap - do I just need to put a 100uF 35V electrolytic across +24V and negative?

[redwire]

Just add a 1MEG pullup at the GX12 pin 5/heater/thermocouple input, to power +24V. It ends up being across the mosfet D-S. This stops the spazzing and freaking out, an open cartridge will now give a stable OPEN error message instead of picking up hum and noise. This is also aggravated by how noisy your PSU is. Your battery does float from PE ground so hum and noise pickup at the tip will be greater. Or add more bulk capacitance to the 24V rail, some controller boards are really cheap and have no 100uF cap there.

The tips have bad connections inside, new ones they sometimes need to be cooked it can sorta work. I think it's just dirty spot welds inside the white caps or in the maybe in the heating element, but using it seems to eventually fix the bad connection.
Some cartridges I have taken apart (caps) and tried to solder that bad connection to stop the drama.

There are also lots of other fixes to T12 quirks.

[spleenharvester]

OK I tried another power supply, this time an Asus ROG AC adapter that outputs DC20.4V. Worked perfectly. So seemingly it does not like the tool battery, any ideas why? (It does still work perfectly after unplugging and re-plugging the tip to clear the error?)