Author Topic: T12 STM32 V2.1S Soldering Station Controller - schematic etc.  (Read 2371 times)

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Offline floobydust

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Here's a schematic I drew of the KSGER soldering station controller V2.1S
Please PM for any corrections and I will keep it updated.

Known Issues:
-The RTC battery goes dead in a few weeks. Remove resistor R10 10k, it adds unnecessary 0.28mA load.
-The encoder body is not grounded which is a problem for ESD.
-The heater and wand cable has ~4uH inductance and -ve spikes occur switching which stress the MOSFET and thermocouple amplifier. A small cap C8 is across the MOSFET to absorb this, but I added a fast recovery reverse diode across the heater.
- The vacuum desoldering pump MOSFETs/diodes/connectors are not populated.
- Silkscreen has duplicate ref. designators.
- S/W 2.10 my cold junction temperature from NTC is not working despite A/D voltage changing. A replacement controller works.

Controller board H/W versions:
2.1S (blue PCB) has pump control and buck-converter.
2.1S (green PCB) has pump control and SPX2954 LDO for 3.3V
2.1  (sometimes called 2.1S) has no pump control and an LDO for 3.3V, not buck-converter.
2.01 fixed the (2.0) LDO overheating, added copper-pour heatsink.
2.0  is a failed design using SOT-89 LDO for 3.3V that overheated from no heatsinking, and no snubber on the MOSFET.
1.5  oddball design using dual buck/LDO vregs, 4-pin GX12 connector like Quicko, and dual op-amp for thermocouple amp. PT Dreamer's Blog reverse engineered it and made custom open firmware for it.

Lately, firmware needs an activation key first run. STM32 CPU ID1, ID2 and then activation codes.

The T12 thermocouple is oddball metallurgy, measured empirically in Hakko Patent US6087631A for the look up table, 20-21uV/°C accurate from 200°-600°C.

edit: uploaded the wrong sch (huge file), fixed, added thermocouple info, V1.5 url.
« Last Edit: July 12, 2019, 02:51:44 am by floobydust »
 

Offline bitwelder

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #1 on: June 06, 2019, 10:41:45 am »
Voltlog was showing some of the station issues in his recent video https://youtu.be/QESGY5LzPPw
 

Offline android

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #2 on: June 06, 2019, 11:53:25 am »
You might want to preemptively replace C8 (Chongx brand 100μF 35V electro) with something from Japan. Mine was open circuit. Edit: oops I meant C4
« Last Edit: June 06, 2019, 12:04:40 pm by android »
Lecturer: "There is no language in which a double positive implies a negative."
Student:  "Yeah...right."
 

Offline voltlog

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #3 on: June 06, 2019, 05:18:39 pm »
After a hint I got from another user on twitter, I assume R10 was intended as protection to prevent reverse leakage current from flowing through the diode into the battery when system vcc (3V3) is present. This is sometimes shown in RTC chip datasheets but KSGER somehow got that wrong and the resistor is slowly draining the battery. I have removed R10 on my unit, problem solved.

Another known issue (but related to the power supply, not the controller board) is poor isolation between primary and secondary, caused by the output diode heatsink which extends on the top side from the primary high voltage tracks up to the secondary low voltage side.
« Last Edit: June 06, 2019, 05:20:35 pm by voltlog »
 
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Offline floobydust

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #4 on: June 06, 2019, 09:51:01 pm »
Schematic I drew of the KSGER soldering station 24V power supply. KSGER 96W 24V 5A Electric Power Supply Unit For STM32 STC OLED T12 Digital DIY Soldering Station Controller.
'Soldering Power V2.04' and pig with bull horns icon on the silkscreen. Earlier version PSU's like V2.01, V2.02, V2.03 look the same but no pads for a mystery DPAK part or have a different DC connector.

I find some clearance/spacings mistakes, a thin PE ground trace, and no connection to the chassis.
The TL431 is set to over 25VDC output and it has no bias resistor. The snubber cap is only rated 100V. Could not find datasheets on the CR8642S PWM controller.

One clearance mistake is the HV DC trace going under the LV rectifier heatsink fin. The diode is insulated TO-220 fullpack, but the heatsink mounting pins/pads have small clearances I was leery about, so I lifted the heatsink and put Kapton tape over the offending trace.

Definitely connect PE GND to the enclosure for safety. This "use a 1MEG resistor" people are advising is only OK for a double-insulated product. There's no approvals here, no idea how the transformer is wound if it would pass the few kV hipot test for the double-insulated test.
 
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Offline Hemi345

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #5 on: June 07, 2019, 05:33:32 pm »
@voltlog, I believe the delay you mentioned in your video on power up might be related to initializing the OLED display.  I've played a bit with these OLEDs and found that I needed to include a 1-2 second pause in my program at startup to give the display some time before I sent the initialization commands to it.  KSGER might be a bit generous in the startup delay to make sure the display is definitely ready to go before trying to initialize it and display something.  Only a theory.  Maybe @PT_Dreamer can chime in on the startup delay as I believe that person wrote alternative firmware for some of these stations.
 
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Offline floobydust

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #6 on: June 07, 2019, 07:47:30 pm »
The power supply takes 3 seconds (on 120VAC) to come up, and then the controller another 3 seconds before the OLED is lit up.
So for 6 seconds I wonder if I have the thing plugged in or turned on. Both delays are too long.

edit: the long boot time 3 seconds is apparently the copy protection and RTOS delay. The power supply is another 3 seconds even after replacing capacitor.
« Last Edit: July 11, 2019, 01:51:36 am by floobydust »
 

Offline Hemi345

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #7 on: June 09, 2019, 02:42:44 am »
I see the power LED on the power supply board light up on mine in less than a second, but no signs of life on the front for a few seconds (with my 2.01 station) so I wonder if it got unplugged too.  It's kind of annoying.  But other than that, I'm enjoying this station.  For the money, it works well.
 

Online Gandalf_Sr

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #8 on: July 11, 2019, 10:33:04 am »
Nice work floobydust.  One WARNING to users of the KSGER V2.1S is that, if you put the station to sleep and power is interrupted and then comes back, the station will come back up ON! At least mine does.

[EDIT]
I'm drawing up a replacement PCB for this, does anyone have the dimensions for the GX12-M5 connector (pins) (I measured this from a new part and the PCB but confirmation would be good.

[EDIT2]
Any part number suggestions for the beeper and the small locking connectors would be helpful too
I figured out the rotary encoder; it's a Bourns PEC11R-4120K-S0018 (the 20K is 20mm shaft length knurled and I could go with a 25mm 25K but they are not as easily available)

[EDIT3]
The AT24C08N 8k I2C flash memory IC is obsolete and there is no stock at Digikey or Mouser; if this design is going to take PTdreamer's code, is the memory actually required? If yes, then can we switch to a SPI device?
« Last Edit: July 11, 2019, 07:26:30 pm by Gandalf_Sr »
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Offline Hemi345

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #9 on: July 11, 2019, 03:33:09 pm »
Nice work floobydust.  One WARNING to users of the KSGER V2.1S is that, if you put the station to sleep and power is interrupted and then comes back, the station will come back up ON! At least mine does.

The default initial state is "ON" when the unit is powered up so that sounds like normal behavior to me.  I have my unit's initial state set to "StandBy" when powered on because sometimes I'm not actually ready to solder when I first turn it on, habit of turning on the soldering iron while getting ready from years of using my old Weller.  It'll also maybe offer a little fire protection in the event it gets powered up without the handle in the stand.
 

Online Gandalf_Sr

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #10 on: July 11, 2019, 04:49:01 pm »
Oh, can you change the initial state?  My point was a safety issue where I had been leaving my KSGER T12 station on standby and then there was a glitch in power and next thing I notice is that my iron is 300 C.
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Offline floobydust

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #11 on: July 12, 2019, 03:38:23 am »
One WARNING to users of the KSGER V2.1S is that, if you put the station to sleep and power is interrupted and then comes back, the station will come back up ON! At least mine does.
Menu 12 to set the power-up state, but it must be Boeing software. If it was sleeping when power goes off, it must only look at Menu 12 setting to run, on power up?

I'm drawing up a replacement PCB for this, does anyone have the dimensions for the GX12-M5 connector (pins) (I measured this from a new part and the PCB but confirmation would be good.
GX12-5 I never found decent mech. dimensions and had to reverse engineer it for the pin radius or was it from a Japanese mfgr I forgot. The PCB has 1.6mm holes for 1.5mm pins, tight fit.
I wouldn't solder a PCB to it - it's murder to desolder to get your board out, if you can do it. The GX mounting nut locks it in.

Any part number suggestions for the beeper and the small locking connectors would be helpful too
I figured out the rotary encoder; it's a Bourns PEC11R-4120K-S0018 (the 20K is 20mm shaft length knurled and I could go with a 25mm 25K but they are not as easily available)
The encoder seems to be a chinese clone of Alps EC11 17.5mm shaft I measure. It's an odd length to match the knob. Watch the underbelly has sharp edges that short to soldermask and short out, you need some keepouts. ESD hits the housing too so it needs some path to GND, a cap or resistor.

The AT24C08N 8k I2C flash memory IC is obsolete and there is no stock at Digikey or Mouser; if this design is going to take PTdreamer's code, is the memory actually required? If yes, then can we switch to a SPI device?
STM32 family has no internal EEPROM, so you have to add one to store settings and calibration for your project or maybe you can use a block of FLASH. There are many other mfgr 24C08 parts i.e. M24C08 ST or AT24C08D Microchip.
A lithium battery is something silly for a soldering station, I could care less what time it is.
 

Offline Hemi345

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #12 on: July 12, 2019, 04:14:21 pm »
Oh, can you change the initial state?  My point was a safety issue where I had been leaving my KSGER T12 station on standby and then there was a glitch in power and next thing I notice is that my iron is 300 C.

Yeah, in your situation, I'd probably set the intial power state to Sleep (I think that's an option), so if that happens again, it'll just boot up to the iron being off.  Note that these OLEDs can burn in the image when left on for long periods of time.  It does that little race track animation after a while (also configurable in the menu) but I'm not sure all the pixels go dark for very long.  Not that it would be hard to swap out the old screen with a new on for a few $ if that happens.
 

Online Gandalf_Sr

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #13 on: July 12, 2019, 09:02:09 pm »
Thanks for all the info.  I've done some work on the schematic today with component selection, here's some notes:
1. There are multiple 1.3" OLEDs available and some have the order of VCC, GND reversed so I have incorporated a cross-patch 0603 resistor setup to handle either.
2. The STM32F103C8T processor is crazy expensive ($6) so I'm considering a Cypress CY8C4025AZI-S403 in its place, I've worked extensively with this processor and they're $2 in 100's
3. The alternative suggestion for the 8k EEPROM was good, I chose a M24C08-RDW6TP which is dirt cheap (15 cents).

What do you guys think about the new processor or could you care less? Changing CPU would mean I'd have to port over the code but I can handle that or share the work with you guys.
I tried to unsolder the GX12 from one of my KSGER's I have a Hakko desoldering tool with a 1.6 mm tip which would seem perfect but I gave up in the end; I can see the advantage from a manufacturer's perspective of having the connector solder to the PCB as it almost makes it impossible to remove without destroying the PCB (maybe a feature rather than a bug?)
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Offline Hemi345

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #14 on: July 13, 2019, 04:52:25 am »
I tried to unsolder the GX12 from one of my KSGER's I have a Hakko desoldering tool with a 1.6 mm tip which would seem perfect but I gave up in the end; I can see the advantage from a manufacturer's perspective of having the connector solder to the PCB as it almost makes it impossible to remove without destroying the PCB (maybe a feature rather than a bug?)

My hot air station made quick work of removing the GX12 when KSGER sent me a replacement controller (replace the board with the crappy SOT-89 LDO w/one that has the switch mode regulator).

It'd probably be better to design it to use wire for connections if you put standoff holes on the board to fasten it to the case.  Or are you planning to use the KSGER case and face plates with your design?  If so, the GX12 soldered to the PCB, keeps the PCB/screen aligned in the case, where as I've seen the screen tilted on the 2.1S because it's only held on one side by the rotary encoder.
 

Online Gandalf_Sr

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #15 on: July 13, 2019, 09:45:33 am »
Yes, I am sure I could remove the GX12 connector using a hot air rework station but it's kind of a weird design. I'm thinking that I will match the form factor for the KSGER as many will prefer this (and I can get all the components onto the PCB) but the PCB could still be put in a more ergonomic case.  In the KSGERs I own, the PCB includes holes to feed wires from so that the GX12-5 can be remotely mounted but they are there because the GX12 connector can be sawn off and anyone could simply run wires from the GX12-5 footprint to the connector.

I looked at PTdreamer's schematic yesterday and he's doing something weird with the drain of Q1 where he seems to be measuring the signal across a diode which, I think, is to do with allowing use of JBC tips - any comments on this and whether or not I should incorporate that into my PCB?

So, I think position of display and controls will allow use in KSGER case but I'll add features that maybe allow for a bigger display.
« Last Edit: July 13, 2019, 10:01:27 am by Gandalf_Sr »
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Offline floobydust

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #16 on: July 13, 2019, 07:20:24 pm »
I would start a new thread for OSHW requirements and design of a soldering iron controller, or porting PT Dreamer's code to these existing controllers. His board is old V1.5 and oddball I would not use it.

GX12-5 footprint I took the 4-pin part and trigonometry to get the pin radius as 3.536mm (9/64"?), hole 1.6mm, pad 2.1mm. Let me know what you find.
The problem is JST connectors to the GX12 pcb can't handle 3A. So it's directly soldered to the PCB which means you will never remove the board and I would rather the solder 5 wires.

The open-source soldering iron controllers I see support 936, T12, JBC. I can help with the schematics for something low cost and not Fendi or Gucci.

These stations use the popular 88mm extrusion out of china for an enclosure.
« Last Edit: July 13, 2019, 07:22:25 pm by floobydust »
 

Online Gandalf_Sr

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #17 on: July 15, 2019, 11:53:48 am »
I would start a new thread for OSHW requirements and design of a soldering iron controller, or porting PT Dreamer's code to these existing controllers. His board is old V1.5 and oddball I would not use it.

GX12-5 footprint I took the 4-pin part and trigonometry to get the pin radius as 3.536mm (9/64"?), hole 1.6mm, pad 2.1mm. Let me know what you find.
The problem is JST connectors to the GX12 pcb can't handle 3A. So it's directly soldered to the PCB which means you will never remove the board and I would rather the solder 5 wires.

The open-source soldering iron controllers I see support 936, T12, JBC. I can help with the schematics for something low cost and not Fendi or Gucci.

These stations use the popular 88mm extrusion out of china for an enclosure.

For 'pin radius', do you mean to the radius to the outer edges of the pins?  If yes then I concur, my measurements have the radius to the center of the pins at 2.5 mm
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Offline floobydust

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #18 on: July 15, 2019, 07:04:59 pm »
Good, hard to find the dimensions with pin radius.
 
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Online Gandalf_Sr

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #19 on: July 16, 2019, 10:15:51 am »
Nice find floobydust.  That clearly shows that the pin diameter for the 5-pin GX12 is 5 mm so my radius is good at 2.5 mm.  I have been doing some more work on the design, I'm leaning towards designing a board that is the same dimensions as the KSGER one so it could be a replacement but that doesn't mean that it can't be made to fit in a different case; I can also change the PCB layout at any time I like.

I also think I'll start a new thread when I've done a bit more work - anyone want to volunteer to port the code over to PSoC Creator? I've already started the project in that IDE.
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Offline mematyi

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #20 on: October 18, 2019, 09:27:22 pm »
Hi!
I just received this station from Banggood today, and it has a "Ve2.12S" marked pcb.  It still shows 2.1S in the menu, but the board is a bit revised. The components moved a little bit, and R10 is simply missing from the board.  My RTC battery came fully charged.
Power Supply is still a 2.04 thing.
 

Online Gandalf_Sr

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #21 on: October 19, 2019, 12:56:17 am »
Cool, any change of a photo?  I should pull my finger out and finish the design for my replacement PCB.
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Offline mematyi

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #22 on: November 04, 2019, 08:11:05 pm »
Hi!
Sorry for the late reply.
Here it is. That Famous R10 resistor is completely missing.
 

Online NANDBlog

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #23 on: November 04, 2019, 08:45:06 pm »
Thanks for the schematic. I cannot believe I even considered buying this. Not even a fuse on the output or on the input. if you micro locks up, the iron becomes hotter than the sun. or if ESD kills Q2 gate. Not to mention all the routing and assembly problems. What a piece of junk.
 
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Offline Johnny B Good

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Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Reply #24 on: November 07, 2019, 02:27:36 am »
Thanks for the schematic. I cannot believe I even considered buying this. Not even a fuse on the output or on the input. if you micro locks up, the iron becomes hotter than the sun. or if ESD kills Q2 gate. Not to mention all the routing and assembly problems. What a piece of junk.

 I do think you're being a little harsh in your criticism and since I haven't contributed very much to these forums of late, I'll explain why and add a little balance to counter this criticism. Incidentally, do you have any reason to think the gate of Q2 is particularly at risk of ESD damage? It's location in the circuit, as far as  can see, makes it no more vulnerable to ESD than anything else within that Faraday Cage enclosure, earthed or not.

 It's true the control unit, as delivered, has some serious electrocution hazard risks due to the kakameemee diode heatsink choice and layout and absence of connection of the PE to the metal casing and ground bonding issues to the controller PCB but these are issues readily addressed by anyone buying one of these controllers as an upgrade to an existing soldering iron collection (and hey! at least the soldering tip is grounded making it ESD safe :)).

 Anyone who has had even just one previous experience of Chinese Kwality in regard of mains powered kit will be well aware of the need to open these things up to make sure that they're actually safe to use (either by them uncharacteristically already being safe, or more likely requiring a few simple alterations to ensure all the ESD, electrical fire and electrocution hazards have been neutered).

 Such modifications are fairly trivial to apply and well worth the additional work by anyone into electronics and DIY repairs/modifications to get their hands on such cheap Chinese bargain versions of kit that could otherwise easily cost ten times as much from Western manufacturers (who can't always be trusted to employ even minimal safety measures - Weller being a case in point with at least one current model of soldering station that has no protective fusing whatsoever).

 As for your "What if?" concern over the cpu locking up and the lack of protective fusing leading to the possibility of a T12/T15 tip glowing "hotter than the sun", that's always been an ever present but vanishingly small risk with any such control systems. The Lord Murphy is forever hovering in the background waiting His chance to punish Humanity for such hubris in believing they have made a totally safe and reliable 'gadget'.

 Most sensible designers (but not the Chinese it seems) don't aim for complete perfection, just enough 'perfection' to avoid suffering punishment of the "Capital kind" at the hands of Our Lord Murphy (i.e. minimal fire or electrocution risk). The Chinese don't seem to be able to distinguish between the level of consequences from their carelessness in design and manufacture of such electrical goodies, hence the safety check on Chinese electrical gadgets being SOP for the seasoned purchaser of such items.

 When you refer to the lack of fusing on the input and output, you neglected to specify the object in question. The PSU for all its faults, unlike the aforementioned Weller soldering station, actually has not one but two mains voltage fuses (a user replaceable fuse in the C14 socket assembly and the obligatory soldered in safety fuse on the smpsu board itself). Since smpsus typically incorporate overcurrent protection on their outputs, I can only assume you're reference is the controller board attached to the front panel itself.

 If this is the case, this is a situation where it would be impossible for any simple fuse protection (on the input or the output of the controller board) to protect against "the iron becomes hotter than the sun." risk. Since it's extremely unlikely that the iron could reach a temperature in excess of 2000K whilst the Sun's surface temperature is reckoned to be three times this at 6000K, this hyperbole detracts somewhat from your expressed concern over the lack of such protection.

 Quite frankly, the only situation where I can see such an event leading to loss of life or financial ruin is where the user needs to be under tight supervision by a competent adult. Making the reasonable assumption that any such soldering tools will normally  only be used in a safe working environment by persons with a reasonable level of awareness of the risks in their inappropriate use, the worst outcome will be merely that of a ruined soldering iron. No biggy in the case of a cheap T12 clone and merely an annoyance in the case of an overpriced Hakko T12 or T15 tip - it's only money after all!

 Personally, if I ever saw my clone T12 tip starting to glow bright cherry red, I'd make a grab for my camera and use the opportunity to record just where the heating element is placed within these "Direct Drive Cartridge Tips" before hitting the off switch. Sacrificing even a genuine Hakko tip is far cheaper than investing in a relatively low resolution infrared camera to obtain such information at normal soldering temperatures. Besides which, photographic or even movie evidence can be useful when making a warranty claim against KSGER or their sales agent. >:D

 Although power transistors have become somewhat more robust during the past half century, that truism about such semiconducting devices being defined as "Transistor - a ten dollar device designed to protect a ten cent fuse", still rings true today. Ordinary fuses, as I've already mentioned, don't offer effective protection against a lock up state that results in the iron overheating. Carefully crafted slow blow thermal fuses, accurately matched to the anticipated fault current in such a scenario could provide some limited form of protection against such an eventuality.

 Considering the rarity of such events (I can't recall anyone reporting such an event with these KSGER soldering stations[1]), such provision of slow blow thermal fusing seems extremely unlikely as well as an unnecessary complication. It's a risk of failure I'm happy enough to accept, especially when I'm not going to be using the iron in such a way as to elevate such a risk to a life threatening level. I would be very surprised if other members contributing to this thread don't also take a similar view of this risk.

 You seem to forget that this product is aimed at a market demographic that will not only be all too grateful to get their hands on such a cheap clone soldering station based on Hakko's T12/T15 soldering iron direct drive cartridge tips but also have the necessary skills to render it safe and reliable for everyday use by applying the most basic of remedial measures.

 However, this does mean it can't really be recommended as a first time purchase to a soldering virgin without access to help from an experienced mentor, prepared to apply such remedial work on their behalf or to guide them in the necessary reworking by way of a practical lesson in soldering (using ordinary soldering tools of course!).

 Your concerns may be genuine if a little misplaced. Regardless of whether they were genuine or not, I thank you for giving me the opportunity to laud both the vices and the virtues of KSGER's cheap T12 soldering station. There are plenty here who see more of the virtue than the vice to go beyond mere remedial work and into the realm of applying hardware modifications to improve on KSGER's own efforts. I think your concerns may have fallen on deaf ears in this thread since I appear to be the only one so far, foolish enough to go where Angels fear to tread and make a reply.

[1] I'd seen an "illuminating" video on Youtube recently which demonstrated the 'glowing red hot' T12 tip but this was the result of mis-wiring a replacement temperature control module inside one of those combined spot welder/soldering station controller units. It was "illuminating" in that it showed just how close to the end of the tip the heating element was (extending just under 20mm from behind where the tip proper starts - impressively compact and right up against the tip itself).

[Edit] It seems I'd slightly misremembered that youtube video demonstration as you can see here:

https://youtu.be/E9eZTspkV0I?t=241

 Nevertheless, it was literally illuminating, demonstrating just how compact and close to the business end of the tip the actual heating element is. I noticed he was careful to use the most commonly supplied K tip which so many reviewers tend to disparage out of hand. Close inspection shows that the heat is somehow being concentrated over the last 8mm or so of the heating element section which may or may not be typical for the K type tips.

 Since the K tip originally supplied with the soldering station appears to have become unstable and I'm now using the one from the pack of ten assorted tips I'd included in my initial order, I might sacrifice the original to a similar test run, seeing as I now finally have a Longwei 30v 10A bench supply to hand (after more than a month's wait for Banggood's "Priority Airmail"  to belatedly fulfil its promise).

 This might actually cure it of its instability (or, more likely, kill it). At the moment it's like Schrödinger's cat, neither dead or alive so I'd prefer to force the issue one way or another and this seems a more fruitful way to resolve it (kill or cure - either is good, as in "All's Well that Ends", there's no need for it to end "Well", just as long as it ends). :)

JBG
« Last Edit: November 07, 2019, 02:54:57 pm by Johnny B Good »
 


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