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Topic: Really universal soldering controller (Read 761902 times) previous topic - next topic

Re: Really universal soldering controller

Reply #3600
I mean he put a very little effort in debugging still and this should be an easy power thing. And you advised to spend $100 on top of already spent $80 or so and throw those $100 in the bin.

I would follow the power path, starting from AC voltage after the fuse. May be measure voltage drop around R9, check R47, R51 divider resistance. The problem with incorrect zeners was already discussed and solved here.

Thx for support. I did not see much of a benefit of moving parts to a new PCB either as the fault is within some components. I personally prefer to document this kind of issues and troubleshooting in this thread as this can help other people in the future. I done some more diagnostics but I stopped getting correct voltage on J3 and zener diodes voltage on ZD2 ZD1 is to low. I suspect faulty Q1 FZT605. I will give some more update once replaced. Once again thank you for support.


Re: Really universal soldering controller

Reply #3601
I suspect faulty Q1 FZT605.
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For experiments, I advise you to put any field operator N channel 60v 20a instead of the 605th, I have installed and have not passed for a long time since I have already replaced the 605x until I have achieved the result, but after replacing it with a field operator, everything works like a clock and no problems

Re: Really universal soldering controller

Reply #3602
Faulty Q1 won't lead to DC detection instead of AC. By all means, you have fault there, but you have also fault elsewhere. Unfortunately without oscilloscope it is extremely difficult to say where it is.

Basically, in order to detect AC, the voltage after rectifier diodes is directly fed to a voltage divider R43-R43, limited by ZD4, and filtered by C60. The voltage on C60, which is rectified sinusoid, limited to just above 3V, is fed directly to the MCU pin, where the MCU comparator reads it. For some unknown reason, you either have a DC voltage on C60 instead of rectified sinusoidal voltage, the valley voltage there is above the comparator's reference point, or the comparator itself is not functioning properly. This leads to a constant high level of the comparator and the MCU thinks that there is a DC voltage on the input power port.

Re: Really universal soldering controller

Reply #3603
I suspect faulty Q1 FZT605.

For experiments, I advise you to put any field worker on the channel 60v 20a instead of the 605th, I have installed and have not passed for a long time, since I have already replaced the 605x until I have achieved the result, but after replacing it with a field operator, everything works like a clock and no problems

FET transistor instead of Darlington for Q1 won't work properly. Q1 is is a preregulator. It is there in order to limit the voltage to the 3.3V SMPS chip. Another purpose of this transistor is to prepare input voltage for "AC valley circuit", comprised of D12, C13, R10,ZD1, ZD2, Q5, R9, C12, D11.

Another purpose is to prepare voltage for Q10 and Q11 gate driving chip.

PS: And you MUST definitely have C8, C11 and C22 in place. I don't see C22 at all, and I don't see C8 soldered in place on your back board.

Q1 is a voltage regulator. MOSFETs cannot do this! I will not be too surprised if you have increased noises here and there for example, different valley voltage,.

FZT605 has many possible substitutes, given the fact that DPAK /TO251 darlington can also be used there. It just needs to be a darlington.

Re: Really universal soldering controller

Reply #3604
Perhaps so, but it works for me at two different stations, although I don’t know how long it will last, but the fact that after replacing I did not feel anything except how the problem with replacing 605x was gone, and all of this is at the stations that are in semi-automatic mode for switching the instrument, one for two 115x,  tweezers and a soldering iron, the second has dr560, 245, 120 tweezers, 210 soldering iron

Re: Really universal soldering controller

Reply #3605
Faulty Q1 won't lead to DC detection instead of AC. By all means, you have fault there, but you have also fault elsewhere. Unfortunately without oscilloscope it is extremely difficult to say where it is.

Basically, in order to detect AC, the voltage after rectifier diodes is directly fed to a voltage divider R43-R43, limited by ZD4, and filtered by C60. The voltage on C60, which is rectified sinusoid, limited to just above 3V, is fed directly to the MCU pin, where the MCU comparator reads it. For some unknown reason, you either have a DC voltage on C60 instead of rectified sinusoidal voltage, the plateau voltage there is above the comparator's reference point, or the comparator itself is not functioning properly. This leads to a constant high level of the comparator and the MCU thinks that there is a DC voltage on the input power port.

I might be ale to put my hands on oscilloscope at my workplace so once I will fix J3 power issue I will give it a try.

Re: Really universal soldering controller

Reply #3606
The oscilloscope need to be isolated if you have connected the EARTH from the mains plug to anywhere. Did you?

And what problem do you have on J3? There should be 3.3V, -0.6V and GND there. Do you have these voltages there?

Make a detailed picture of your back board around U1 and Q1 please.

Re: Really universal soldering controller

Reply #3607
Perhaps so, but it works for me at two different stations, although I don’t know how long it will last, but the fact that after replacing I did not feel anything except how the problem with replacing 605x was gone, and all of this is at the stations that are in semi-automatic mode for switching the instrument, one for two 115x,  tweezers and a soldering iron, the second has dr560, 245, 120 tweezers, 210 soldering iron

You don't have anything limiting the Gate-Source voltage on this MOSFET, and you can have potentially more than 25V there. So I am not sure how long will it last, unless you install a 15V zener between gate and source. Fortunately at least you do have reverse gate-source diode there


Re: Really universal soldering controller

Reply #3609
FZT605 substitutes:

- MJD112
- MJD122
- MJD6039
- FZT600
- FZT603TA

Talkos, if you insist using your MOSFET, at least put a 15V zener instead of D5. Oriented the same way as D5 - cathode to gate, anode to source.

Re: Really universal soldering controller

Reply #3610
The oscilloscope need to be isolated if you have connected the EARTH from the mains plug to anywhere. Did you?

And what problem do you have on J3? There should be 3.3V, -0.6V and GND there. Do you have these voltages there?

Make a detailed picture of your back board around U1 and Q1 please.

Thank you for your support on troubleshooting this issue. On the very begin before I attached a front PCB I measured a voltage to ensure J3 pins gives correct voltage. Everything was fine until yesterday. From unknown reasons voltage is no longer there.
Q1 needs replacing as I do not like a slight crack in the middle of this component.  Picture of my U1 section below . Forgive me exposed mask but tracks are still fine. 


Re: Really universal soldering controller

Reply #3611
Q1 seems dead.

I keep wondering WHY this Q1 gives you (and two more people I know of) so much trouble. You may replace it with one of the proposed substitutes - MJD112/MJD112. These are in different package, but the back also supports DPAK/TO252 package anyway.

What display are you using? (I saw. It is not the display)

Where did you get FZT605 from?

PS: And just out of curiosity - is lead free solder used?

PPS: ZD3 is in wrong package!!! You should use a zener in SMB package. The one you used is too small and low power. I cannot be sure that the problem is there but it is in wrong package anyway.

PPPS: My FZT605 looks different. The designation is at the center of the package. Yours is closer to the left side. Where did you get it from?

Re: Really universal soldering controller

Reply #3612
Hello! My friend. Now feedback a question about your design for contact hibernation. After we drew the pcb and welded it, we set it to 180 degrees, we could sleep to 180 degrees, but when we reached the set temperature, we suddenly warmed up and then cooled down, repeatedly

Re: Really universal soldering controller

Reply #3613
3V diodes arrived and I just replaced them. Measured voltage between ZD1 ZD2 5.5 and still detected as DCF. Any more suggestions.
Can you try replacing the REF3030, maybe

it's possible to help you