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CharlesFoster

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Everything posted by CharlesFoster

  1. After replacing almost everything i got it working. This inverter works different than the other brands. soft start is purely switching one fet on, and then the rest for high current.You will see on the PCB one fet on the bank is driven by a separate IC. So in your case i would start with the bank (in my case with 2 heat sinks) check those fets and drivers. I saw the resistors burnt as well once those banks were off, so i replaced the drivers, the resistors and the fets. Mine is not 100% yet as it trips above 10% usage now, but seems to be a current sense circuit. I have to take it apart and check further.
  2. okay, sorry....big mistake. that is the SPS circuit i am busy with, not soft start. So starting over again.
  3. Another follow up. Seems Diode D1 as per image does not go to the 400V. Disconnecting it also made me fry the comms board. don;t use it, so no harm...yet. From the TX1 one side goes to R31 resistor, then D2 diode, into U15(79L12 regulator.) I have not tested output on regulator yet, but seems futile since it can not be my 400V then. So, it actually looks like this is not my soft start circuit then at all, but rather some small DC-DC psu. I am going to try and trace back from the caps and see if i can find the soft start.
  4. okay, so here is what i did and found. I measured frequency on drain of FET, found 250khz that seems very strange but okay, i left it there for now. I removed the IGBT's in order to separate the high current 400v from the soft start. Voltage on 400v caps still below 3v. I removed the 400v caps, tested them, they seem fine and within tolerance. 480uF and 510uF. The thing i can not find is the link between the diode and the caps. i find 2 little isolation transformers going to IGBT's but no direct link to the cap, on either positive or negative. so i assume there is something in between that i need to find first. schematic would really help about now. I in fact not 100% sure i have the right diode where i measure, although on the output of the transformer.
  5. hi, Thank you for the reply. I do not have a scope to measure the frequency, but tried with the DMM(i have a Toptronic / Brymen TBM805), i get 52khz stable. As for the voltages, vRef - 5V and iSense is 80mV. Yes, the yellow transformer bottom right hand is the one involved in soft start. From what i could deduce: The top part with large transformer(above heat-sink) is the main PSU / Inverter. Lets say high voltage side. Below heat-sink is the battery charger and DC-DC soft start. Heat-sink with encapsulated toroids seems to be the solar parts. The heatsink has all the IGBT, Diodes, bridge and FET's on. All tested(circuit / functional testing, not DMM) and working
  6. Starts off on 0 and climbs to 3.5v before E09. if i restart the process it climbs about another 2v. I have checked UC3845 supply, 15V is there. i get 1V on the FET gate, so i think it is not switching. i measured resistance on UC3845, pin 7-5 42K and 6-5 32K but still think it is blown. Diodes around the circuit tests fine. Also added picture of circuit in question.
  7. hi Guys So my inverter started giving error code 09. As per all the forums and advice i started first with the IGBT's. They are all fine. The mosfets are all fine, diodes all fine. caps are fine. I could not find a single part faulty yet. The schematic i have differs a bit from my unit, so difficult to follow all the places to check. Any body that has a better schematic or even advise were to check further? Axpert MKS 1-3KVA Service manual 20130611.pdf
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