Variations between Hakko T12 DIY kit stations

[crystallattice]

Hi,

Has anyone done any comparisons between the various Hakko T12 DIY kits to explore their strengths or weaknesses or functionality?

I recently bought the DSK T12-D variant. I took it apart and it seems pretty decent, with a "proper" PSU not a salvaged Apple unit and also proper grounding. Haven't done much more testing other than trying out the sleep function which switches the iron off after 15min and claims to shut down the unit after 30min.

Unfortunately, shaking the iron wakes it up (ball type vibration switch) even in "shutdown mode" I was expecting that only the encoder button should be able to do it once in shutdown. I wanted to change the sleep time to say 5min and replace the vibration switch with the more sensitive spring type but this will not work due to the improper shutdown function. Pressing the encoder button puts it back in sleep though.

Another disadvantage is that it does not enable any parameters to be changed. The controller is based on some 8051 chip not the more popular STC chips.

Maybe there is some other firmwares available but I have not managed to find them.

At the moment the unit is very usable and still worth the money but at some point I would like to change the sleep/shutdown function.

I'm also looking at another handle for a spare and it seems cheaper to buy another handle + display kit than to buy the parts individually, this gives me the opportunity to solve the sleep/shutdown issue and has led me to a few STC variants but mainly these two:

One with adjustable opamp offset/gain(x2? - P04 and P11) and PID parameters, but only with a shutdown function (no sleep?):

P01 ADC reference voltage (obtained by measuring the TL431)
P02 NTC correction (by setting the temperature to the lowest reading on the digital observation)
P03 op amp input offset voltage correction value
P04 thermocouple amplifier gain
P05 PID parameters pGain
P06 PID parameters iGain
P07 PID parameters dGain
P08 automatic shutdown time setting 3-50 minutes
P09 restore factory settings
Stepping P10 temperature settings
P11 thermocouple amplifier gain

And the other with opamp offset/gain adjustments but with sleep and shutdown (no PID):

P00: restore the default parameters (0 or 1, the default value of 0,0 for not recovering, 1 for the recovery)

P01: Operational amplifier gain (200 to 350 times, step 1, default 230)

P02: Operational amplifier offset voltage (0 ~ 250mV, step 2, the default value of 100, refers to the tip to keep the room temperature operational amplifier inherent output voltage, according to my measurement this voltage varies greatly with temperature, different magnification Not the same, the higher the magnification, if you do not measure, please keep the default value)

P03: thermocouple ? / mV data (30 ~ 50, step 1, the default value of 41, refers to the thermocouple need to temperature how much voltage was increased by 1mV, according to the type of thermocouple self-calculation, if you do not understand, please keep Defaults)

P04: temperature adjustment step (0,1,2,5,10 degrees optional, 0 can lock the soldering iron temperature)

P05: sleep time (how long don’t not move into sleep) (0 ~ 60 minutes, step 1, 0 is to forbidden the sleep function)

P06: Shutdown time (0 ~ 180 minutes, 0 ~ 30 step 1,30 ~ 180 step 10, 0 is forbidden shutdown function)

P07: temperature correction (+20 degrees, step 1) (due to NTC resistance in the chassis, the soldering station heat will lead to the detection of NTC temperature higher than room temperature, resulting in high temperature compensation of the thermocouple, soldering iron temperature is not accurate,or other causes the temperature is not accurate.If you set the other parameters are correct value but the temperature is still high or low, you can use this parameter correction.For example, to detect the displayed soldering iron temperature is 20 degrees higher than the actual value of this parameter Set to 20)

P08: wake mode (0,1, 0 in the shutdown mode can be rotated the encoder and also can shake the handle to wake up, 1 can only rotate the encoder wake up (Note: press the encoder can not wake up, can only rotate) )

P09: temperature increase mode to increase the temperature to adjustable (20 degrees to 100 degrees adjustable, adjust the pace of 10 degrees)

P10: temperature to increase the duration to adjustable (adjustment range of 10 seconds to 250 seconds, adjust the step 5 seconds)

P11: Parameter setting mode Auto save parameter and return to heating mode Function to active time adjustable (range 4 seconds to 60 seconds)
 
Can anyone with these two variants comment on the sleep/shutdown functions and also the temp stability/accuracy?

Or alternatively point to the source code for one of these so one can make custom changes?

[Decoman]

Btw, I am currently interested in maybe getting a T12 like digital soldering station, and I was surprised to see in a video, that the DIY kit assembled by a youtuber, did not have grounding wires for grounding the chassis, which the reviewer stressed as being critical for safety. This made me wonder if maybe the T12 units solds assembled, also don't come with proper grounding.

It should be pointed out that I am by far not familiar with electronics, but somehow I think grounding issues, or the lack of it, would be imperative for maintaining a minimum level of safety.

This was the video I was watching, in case anyone was wondering:


Grounding issues discussed from the 4:50 & 9:30 time marker.  Presumably this guy knows what he is talking about, but what do I know.

Edit: Hmm, ah hold on. This is now a little confusing. I just noticed that a photo of a T12 like product has the "ESD Safe" text on the front side of its panel, but that seems to be similar to the linked video that discusses the lack of grounding.  Eh, so apparently, it is important to ground the soldering iron itself, and also the chassis. Some other video seem to claim that a continuity test for the soldering iron part was grounded on that particular unit, but he guy seemed unsure and explicitly said he was unsure when doing the continuity test with his multimeter.

[thm_w]

My assembled T12 unit had a proper power supply, and the tip was grounded to earth. However, the case was not grounded, so I added a screw and wire for that.

https://www.aliexpress.com/item/2017-STC-T12-Digital-Soldering-Iron-Station-Temperature-Controller-EU-Plug-Temperature-180-450-Degrees-T12/32803295956.html

[sn4k3]

I recommend a good DIY kit, that way you do the connections as you like. I advice to direct solder everything, get rid of connectors