@marco: Go to calibration mode (without instrument attached) and measure the current between SENSEA and VOut1-. It is microamps, so set your multimeter accordingly. When CURRENT: 0 128 is shown on the displey, the current must be around (1.225(current source voltage reference = 1.225V)/1600(current sources shunt resistance = 1500+100=1600 ohm)/256(current source digtital pot steps)*128(what the display is showing) = 382.8125uA.
You can now measure the current between SENSEA and GND
The result was the same for both VOut1- & GND = 381.9 UA. Shall I remove the mosfets or no need ?
Thanks for trying to solve my issue but my board is at the workshop so I will check it tommorrow. I am a bit confused since did not understand everything I hope my friend have better understanding then me. Shall I remove the Mosfets(Q2,Q10) or do the microamp test do these lead to same test?
If you give up I am ready to buy your board €60 Thanks for offering money for non working board but by give up I mean spend more money and replace everything I really need this unisolder to work. Re Flux We can confirm that not all chips had flux after remove so we are seriously thinking this board already had previous repair attempts disappointed but at least I have you guys with awesome support.
We have replaced U2 and U3, on bootup without Tip I notice a problem heater open flickering with Sensor open very fast. After I connected the iron tip the 511c came back I am very frustrated now and have no clue how we can do further testing. We are not electronics guys but we build battery packs for hobby. Is there any way we can test Q2 and Q10, €27 already gone so I am thinking of giving up. Thanks
Iron > mosfet Q8,9,10,11 > driver U2 > Nor gates U3 > CMOS SPDT Switches U16 > PIC U5 (HEATER) Sensor > MOSFET Q19 & Q22 > Op Amps U12 > Digital Potentiometer U10 (SENSOR A & B)
Thanks for your time, My friend have removed U16 , U12 , U10 one by one, The problem still persist 511 still on display. He Removed U2 and problem was gone, we are not sure if it is U2 or U3, I went to buy both but they are not in stock they should send within 24 hours express. So you was correct the problem might be on the BACK I will put an update. Regarding Shorts to GND we checked all components all seems fine.
Let me explain what is happening when I connect no iron it work as it should, I can change temp to any value. I can enter in menu with no issue. When I connect the iron it remain COLD, on screen it will appear 511C and rapid switch to sensor open and goes back to 511 C at fast rate (200MS) in a LOOP. I still believe the issue is on the front pcb but honestly we did nothing for this to occur in the first place and we also have no clue what to buy and remove next without replace everything. The iron is set to 340c but it get override with 511c not sure if that is the MAX set in code. It can read my Iron when connected using T12.
carefully check connections CNTR, J4 CNTR, J2 IRON. These connector look fine and without iron connected the screen work fine NO Instrument.
Could it be that your friend did this new fault while replacing the U8? My friend had access to the front board only and he did a quick swap using heatgun. Could it be that other chip on the front do this symptoms ? I do not wish to touch also the back board unless someone is sure what to replace.
My friend said that the amount of Flux there is can cause corrosion on PCB assemblies. U11 was not replaced, I just bought it to make sure I can replace it if need, I can guarantee for myself that the pcb was installed in a wooden mdf box and was never used out of that box and the issue happened while it was working in the box. My iron still work fine with the orignal T12 station.
Anyone can put me on the correct track please 511c / Sensor open ---- flickering and iron not working.
Thanks guys I bought New U8 and New U11, at the end it was U8 dead, My friend notice that the board was not cleaned the amount of flux that exit from under the chip is not acceptable he said that may lead to other issues by time and it will fail again with the amount of flux there was I notice another problem on boot up it come 511c / Sensor open ---- flickering and iron not working. I have no clue what happened to this pcb but I am starting thinking to replace all chips, I checked with Conrad and they almost have all parts which is 30 mins drive from where I live my friend is willing to replace all for €15 which will include cleaning. Your suggestion is welcome guys.
May I know which chip please is that and why it went dead I bought this back in December and use it 7 times inside a wooden case I do not have the tools to touch this pcb, I bought this to make battery packs wires but I can ask my friend to help. Thanks
I need help with a pcb 5.2 I bought from tindie. For the past days have been trying to contact lovediy but I get no reply back. The pcb was installed and was working but couple day ago it is giving me 45 on the screen and nothing else, tried to remove all cables but have same issue persisting. I have to say this was a mistake since I am not happy with the work on the pcb,
I am using 60w powersupply dc with T12 iron, any help please maybe I am doing something wrong and it is something I missed but it was working?
I notice another problem on boot up it come 511c / Sensor open ---- flickering and iron not working. I have no clue what happened to this pcb but I am starting thinking to replace all chips, I checked with Conrad and they almost have all parts which is 30 mins drive from where I live my friend is willing to replace all for €15 which will include cleaning.