Reverse Engineering the Gema Powder Coating Gun Main PCB (Part 2)
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- čas přidán 10. 11. 2023
- This is the follow-up video of reverse engineering a commercial powder coating gun main power supply PCB to know how they work. In this video I power up the board and test each functional blocks. Link to video part 1 below:
• Reverse Engineering th... - Jak na to + styl
Google transl. Could you please clarify the supply voltage for IC1? If from 5 volts, then IC1 will not be able to control the Q6 base. Maybe the power comes from 18 volts?
Hi. After I read your comment, I run the circuit in LTSpice simulation once more and it does work. The supply volage of IC1 is indeed 5 volts. Take note that IC1 is a Voltage Comparator IC, not a regular op-amp. The output stage of a comparator IC is an open collector, grounded emitter NPN transistor. So, the output of IC1 toggle between "open" and 0V. During the "open" state, the voltage at the output of IC1 is same as output of the LM2596 (12 volts in the video example) because of resistor R30 and R31 that act as pull-up resistor. During the 0V output of IC1, R30 and R31 forms the bias volage for Q6 in which the voltage at the base is less than the voltage at the emitter and so it turns ON and so forth. I demonstrated this at 6:58 in the video. You can check out the data sheet of LM397 which is a common comparator IC for reference.
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I just ordered the TCL-3 pcb which is similar to this one but they only sent a cascade with 2 wires, therefore I don’t think the current limit will work will it?
Hi. I found the same board in Aliexpress with the cascade having only 2 wires. I contacted the seller just by curiosity and they replied to just leave terminal 5 disconnected. So yes you are correct, in this case the current limit does not work. Actually, the current limit only works if you sent the uA low enough. If the uA is set to high or the kV is set to low, then the current limit will usually not kick in.
Just to add that some models only have 2 wires and the current limit is set to the power supply itself. So it really depends in the circuit design.
Are you powering with just 18v dc? I assume it normally takes 18v ac but because it’s rectified anyway then 18v dc is ok?
Also do you know which transformer it would typically use?
@@MrBrettStar Yes, I simply connect it to my bench power supply. The photo I saw uses a toroid step-down transformer. In my upcoming video I put this board in an enclosure and uses a switching mode power supply instead of a transformer. 18V is the info I found online but exact value is not very important because you will turn down the voltage anyway to adjust the kV.
Hello! Tell me, what is the budget for this build? Will the diagrams be freely available, or can you make it to order?))
Hi. Just look at Part 1 of this video and all the circuit diagrams are already there. Depending on your location, it may be cheaper to order the ready-made kit from Ebay or AliExpress. These Chinese-made products are cheap. Link to Part 1 below:
czcams.com/video/OCLsUD94baU/video.html
Brilliant job as usual Phil. I look forward to seeing the final outcome with the project
Dear brother good project
Pcb garbar file link
Hi bro. I reverse engineer and redraw the circuit diagram only but did not go through pcb layout.
Can you do like this pcb without limiting curent circuit
Yes. I found the same main board in AliExpress sold as a kit with the powder coating gun and hv cascade. However, the HV cascade only have 2 wires so there is no 3rd wire to sense the current. I contacted the seller and the say just leave terminal 5 open of the current limiter open. So in that case, the power supply works without the current limiter.
I tried your oscillator in multisim but not worked
@@amineaissat2485 I run the simulation in LTSpice. I used 0.001H as the inductor load. It will only work with inductor load. The output waveform have very high negative peak (because of being ideal components in simulation). I only guess the values of capacitors because the surface mount capacitors has no markings.
I have all values of component
Give me your gmail and i will give you my schématique