I have 2 complex of temperature contoller and sensors! I have problem with one of it’s: When connect to AC Power suply it shows on display “Fail” as should, bet if i push SELECT button it allow to set time and set others value, but show temperature: -50. This happen with not connected sensor. when connect sensor nothing change (sensor has DC power supply) So it doesn’t show temperature (no changes when connect temperature sensor which works perfect for other controller). Also after pushing SELECT one loop HI ALARM (LD4) stays on.
I have measured voltage on R8 and ground it is around 5 V, directions of diode D3 is correct. Read in forum before that C7 shoudn’t be installed (delete memory), so i disconnected one side of C7 from PCB (but before was connected).
What could be problem and solving of this??
Thanks in advance! Any suggestions are welcome…
The temperature controller can’t measure the temperature.
You must check the PWM output of the K6001, if this give a square signal (PWM output) the problem could be the optocoupler or a false contact between the 2 pcb’s on the K6002.
[quote=“VEL456”]The temperature controller can’t measure the temperature.
Yes i know it. I mention it just to point that it shows it without sensor, which is not correct and possible.
You must check the PWM output of the K6001, if this give a square signal (PWM output) the problem could be the optocoupler or a false contact between the 2 pcb’s on the K6002.[/quote]
I assume that K6001 is OK, because i use it in other temperature controller (K6002) and is working perfect.
I test optocoupler and it seems working good.(Put on input 12V, DC 15mA current and measured the voltage on IC2 25 pin, which changed from around 5 V (without input) to smaller around 1,2 V (can’t remember the number now) when put on input) So i assume it works as it should.
Have left just idea to check if circuit connected to first pin works.