Skip to main content
Topic: Simple DIY JBC soldering station (Read 53856 times) previous topic - next topic

Simple DIY JBC soldering station

My learning project based on several great information sources:
HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron driver
My HAKKO classic and T12/T15 soldering controller
eSol - DIY digital soldering station for 80 Watts Weller iron WP80
Thanks guys!

Current status: transformer inside old PSU housing as temporary solution. I don't want to mess with mains on my desk.
For now battery powered (3.2V LiFePO4) logic part. Opamp, Atmega328p, three buttons, LCD (waiting for b&w OLED instead of this one for better contrast and faster refresh rate).
Next stage: logic level triac driver (or two MOSFETS), first tests, PID controller.

(UPDATE) Other sources:
JBC soldering iron stand wiring
EEVblog #472 - JBC CD-2BB Soldering Iron Teardown
JBC T245 Handle disassembly
JBC Industrias S.A. - EP1086772 A2 - Electric soldering iron patent

Re: Simple DIY JBC soldering station

Reply #2
Beautiful breadboarding!
Got a question? Please ask in the forum for the fastest answers.

Re: Simple DIY JBC soldering station

Reply #3
Some initial tests posted on YouTube:
1. thermocouple reading test
2. power control test
3. solder melting

There is problem with ADC reading, I need to ensure tip is not powered while TC reading.

-Investigate MOSFET driver instead of logic level triac. IRFZ44N looks like good candidate.
-Simple PC app for temperature and power logging over serial line.
-PID controller.

Re: Simple DIY JBC soldering station

Reply #4
any links for the handle on ebay or the like?

I really like the quick replacement of cartridges ;D

Re: Simple DIY JBC soldering station

Reply #5
Unfortunately no, T245 purchased from
They have also AD623 and other components I'm using for reasonable prices.

Re: Simple DIY JBC soldering station

Reply #6
I just found Kst real-time data viewer. Fast, clean, it just works - very nice open source project!

First C245-903 log:

Re: Simple DIY JBC soldering station

Reply #7
Use PMOS to control it with rectified and non-filtered voltage from transformer. It is easily done this way.

LM258 are no good for thermocouple. It has HUGE offset.

The best way to read the thermocouple is with differential (instrumentation) opamp, connected to outer shell as a minus and to the last terminal (the thinnest one) as a plus. This way the inductive peaks from heater resistance will not mess with the measurements. It is a bit harder to do it this way (you may need opamp with positive and negative power supply), but I think it is the right way to do it.

Use MCU with hardware multiplier (I am not familiar with ATmega-s) - you will have more freedom with PID implementation.

Re: Simple DIY JBC soldering station

Reply #8
Sparky, thank you for feedback, I really appreciate it.

Regarding opamp: I'm testing AD623 connected as you described and it behaves strange. There is a lot of noise on AD623 output:


I'm also getting only 1.2V output max, regardless of VS+ (testing on 3V - 5V) and gain resistor value. I did test standalone AD623, just power supply, gain resistor and voltage divider with potentiometer instead of thermocouple. Output seems to be VERY nonlinear, no chance to get output over 1.2V with JBC thermocouple voltage on input. I don't get it, maybe I should look at another opamp when I see arhi's TC reading noise level.

I have power supply inputs decoupled on both MCU and AD623 according to specs.

Here is noise level on AD623 output:
I'm reading AD623 output in the same phase (zero crossing), but it still seems noisy to me. 60mV of noise on 0 to 1200mV scale I can get from AD623 output.

Re: Simple DIY JBC soldering station

Reply #9
As I said, you will need bi-polar power supply for the opamp if it is connected this way.

For example, in the latest version of my controller (I will publish it after I have a working prototype), I have +3.3V and -0.6V. Tha gain of the input buffers is low - around 2-3. This way it has more than  +/-100mV input voltage and can be connected in any way. Then, after the buffers, i have a third amplifier where the big gain is. This way, havng only -0.6V negative supply, the amplifier is able to have +/-100mV input voltage. I am using buck DC-DC for the +3.3V supply, and it becomes +3.3 / -0.6V with very simple and cheap modification with additional 4-5 components.

...and, I am using self zeroing amplifiers for this. 3 of them, in order to be able to control the gain of the input stage, and the second stage. If you use instrumentational amplifier you don't have control on this, and you may need +/-3.3V for example, otherwise the input stage will not be able to handle negative input common mode voltages.

Re: Simple DIY JBC soldering station

Reply #11
I'm busy with my job, but I will continue soon. I'm sorry for delay.

Re: Simple DIY JBC soldering station

Reply #12
[quote author="jry"]I'm busy with my job, but I will continue soon. I'm sorry for delay.[/quote]
Very cool project !
I'm waiting to see it finished, cause i want to built one too :)

Re: Simple DIY JBC soldering station

Reply #13
I'm very excited to see the outcome of this project. I wish you great success and to our fellow geekers who will be replicating your great work.

Re: Simple DIY JBC soldering station

Reply #14
Yeah me too ! It's one of the best DIY SID :)