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OK. Now problem is resolved PCB was bad.
I have build new PCB, all component are from my last PCB, and now Solder station work very good.

It start, when I click, example 200 C, from 62 to 200 (in my room is temperature about 30 C), then green led diode is on and red is off, solder iron have heat ...

Is this design of PCB OK?

Please, can anyone put here good PCB board?
PDF, Eagle or any other format.

Here is my version of PCB.

I do not know what happens.

Thermocouple is connected on pin 3.

Have anyone good PCB in PDF or any else format?

I will make new PCB.

mr_kot measure was on pin 1.

Vseryj On which pins must I put 470 nF? Must capacitors be electrolityc or normal ceramic?

Input voltage on LM358, when display show temperature:

on pins:

2 - 0,01 V
3 - 0,01 V
5 - 0,34 V
6 - 3,82 V

Input voltage is: 5V
VCC is: 5V
AREF is: 2,51V

I have one transformer with 17V (3A) and 6V (1A) on secundar, 2 Greatz, both of Greatz GND is connected on PCB together.

I have try 3 LM358, all are new, and all the same thing, solder iron is heating but numbers on display goes random, strange ...

Thank you for answer.
You think my LM358 is not OK?

On monday I buy new one and again try. Maybe this 2 is realy bad.

I have checked circuit arround LM358, and now when I put 200 C, on display start count but only from 0 to 6, after that, about 20 sec. on display show " Err".
Heating of my solder iron is OK.

I have try with 2 new LM358 and same.

Problem is still here.

Hello mr_kot,

Voltage is:

With power on, without solder iron connected: 3,69 V
With power on, with solder iron connected: 0,53 V
With power on, with solder iron connected, and 200 C start point: voltage go from 0,89 V to 1,89 V (random, strange behavior)

Now I have LM358 in my solder station project.
But, when I put temp 200 C or anything else, on my display I have strange behavior with numbers.

Without iron solder connected I have, when I click on " - ", immediately " Err ". With solder iron connected I have strange behavior with numbers.

What is ...

Martin76, thank you very much for info.
Tomorrow I buy LM358.

Today I have try with my solder iron.
Solder iron heating when I press " - ", but on display I only see number 0 and 1, red led diode is always on, and after about 30 sec. on display show "Err".

On Pin 21 on Atmega8 now I have 2.5 V, but on pin 23 voltage is 0V, also on Pin 1 of LM393 is 0V all the ...

Victor_P. you have right. Огромное спасибо.

Instead of R6 which must be 1 KOhm, by me was 5 KOhm, that was my big mistake. For now I have no more "Err". Now when I with " - " put 200 C, on my display go numbers 0 and 1 and red led diode is on, and after about 30 sec. then display show "Err ...

Anode is on GND, Catode and REF are together connected and have connect with Pin 21 on Atmega8.

I try found another TL431 and try with new one.

Thank you Victor_P. for answer.

On Pin 21 I have 0.14V and on pin 23 I have 0V.

Please, what is problem?

All components are like on schematic, only I have install LM393 and not LM358. Is that maybe problem?

Hello to all!

Please, can you help me.
I have build this project for soldering station, and I have problem:

When I power on my solder station, on displays write " OFF ", when I click on " - " then I have on display " Err ".
When I power on my solder station, on displays write " OFF ", when I ...