November 29, 20223 yr Hello I have a VMII plus 5,5kw. I have change some of the mos fet and when I do that, i saw a small transformer has got a brown colour. I did some measure a round it and it was a short circuit. I take it away from the board. The short circuit was gone. My problem is, I can't find a similar anywhere. It is marked "12.7.16030121 XR" The place for it on the board is marked "TX7" Please, if someone know where to find a new one or a similar one, or just what I can replaced it with, I would be very grateful. And please, excuse my bad English. Anders Johansson Sweden
November 29, 20223 yr Hey Anders, welcome! I have also had to replace transformers in these Axpert VMIIs and it can be quite a pain to get an exact replacement. I cannot remember where TX7 is, is it a part of the AC-Bus circuit or could you send a picture of where in circuit the transformer is?
November 29, 20223 yr Author Hello, and thank You for answer. I will try to post a picture....It is located in the upper left corner.
November 29, 20223 yr 1 hour ago, Grindstugan said: I did some measure a round it and it was a short circuit. I take it away from the board. The short circuit was gone. I assume you mean that it was short circuit winding to winding; each winding will appear to be a dead short at DC (e.g. when measuring with a multimeter). TX7 is the isolating gate drive transformer: So you should measure zero ohms pin 1-2, 4-5, 6-7, and 9-10, but not any other pairing. These transformers are all custom; you can't buy them off the shelf. So they have to be carefully repaired, if needed, or you cannibalise one inverter to repair another. The transformer in the photo doesn't appear burned, but perhaps it's just the angle.
November 29, 20223 yr Author Hello! You are right. Thank You! I have done the measures between the pins as You show me. No short circuit between the pins except for 1-2, 4-5, 6-7 and 9-10. Thank You again, I will now put it back and proceed with the other mos fet. Best regards, Anders Johansson
November 29, 20223 yr 3 hours ago, Grindstugan said: i saw a small transformer has got a brown colour Hi @Grindstugan is the brown color you see unusual, i.e.does it look like burn/heat marks? If so can you show close up of this.
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