January 18, 20251 yr Hello! I have an EASUN SV IV inverter and suddenly it stopped and started to smell like smoke. After disassembling it, I discovered several burned areas on the main board, I circled them in the image below. I discovered that the D54 (MUR460) diode is cracked and shorted. The transistor probably Q35 and the resistor R229 burned completely (since the entire area was burned, I was unable to read what the names of the components were). After removing the burnt parts, I started checking the board for other faulty components. Can you please help me with the name of the transistor and the value of the resistor?
January 20, 20251 yr On 2025/01/18 at 11:40 PM, CuriousMrDog said: Can you please help me with the name of the transistor and the value of the resistor? My guess is that the "transistor" is actually the 78M05 voltage regulator. If the resistor is in series with a small capacitor across a power diode, it's likely a 22Ω snubber resistor. I'd consider resoldering the pins of that power transformer (the large square one near the blackened components); there is a small chance that there is a cold solder joint, and that may have caused the problems. You could trace out a few components around the burned D-pak device to make sure it is the 5 V regulator: The component designators may be different, though a few seem to line up (e.g. Q36 diving the transformer). D54 is probably as above, though that's in the 12 V circuit, and the other burned components seem to be in the 5 V circuit. There is a lot of damage there; it's possible that this inverter isn't practically repairable. But good on you for trying.
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