Hi,
I have a faulty Multiplus that the repair centre was unable to fix as they don’t do board level repairs.
I have located two damaged resistors, but can’t ID them completely. They are R27 and R28 on the back of the contact board. They appear to be 5 band, 1/8W, Band colours - Yellow, missing, missing, missing, Brown. So either 470 ohm or 4k7 ohm, probably.
Anyone perhaps know off hand or have a board they could check for me please.
Photos attached.
Thanks.
@oneoke
Knowing what inverter exactly)HQ number- board number or HW revision) may narrow down who can help you.
Some stuff is in the photos. But not quite enough to evaluate if i have the same one.
@oneoke edited with the picture i was trying to take 
Absolute legend, exactly what I was looking for. Hopefully that’s all that needs replacing to save the board. Much appreciated.
Good luck in repairing it.
Still, it doesn’t hurt to wonder why those resistor burned…
They usually don’t, especially such low power resistors.
Are those the supply resistors for the SMPS IC above?
I also wondered. They dont usually just burn out.
The joys of electronics are about to be discovered…
Agreed, unusual for resistors don’t burn up unless there’s a short near by. Was all working fine until I turned off the inverter and battery, as it was running low due to a power outage. Once the solar had charged up the battery again, I tried turning it back on, but it would not turn on at all, no pass through, no charger only, no leds, nothing. So off it went to a victron repair centre, only for the repair to cost nearly double what a new unit does. I’m going to give it a go, before it becomes scrap.
Before powering it up, please verify all actives in that power source.
Diodes, transistors, etc, especially the power one on HS2, probably T1, as T2 and T3 are the small ones.
The other bit of info I got from the technician is that the board wasn’t powering up via AC or DC. The inverter worked fine when they swopped out the board for their test board. I was thinking of pulling T1 off and replacing it as it right next to those two resistors, otherwise no visible damage. Thanks for the advice.
Usually that type of SMPS has an IC that is powered at startup from the AC side through a big value resistor.
It just needs a small energy in order to “fire-up” a few pulses through the HF transformer with the use of T1.
Then a small winding on the HF transformer will auto/self-power it further, through a rectifying diode and a small value resistor.
This is why I’ve asked about those resistors if they are the power supply ones.
It may well be that the IC itself is malfunctioning (having a short inside) and it’s burning up its own supply resistors…
I removed T1 and tested it, it’s completely shorted out.
Usually when SMPSes goes up in smoke, the drive FETs are shorted. 
This is why I’ve suggested verifying it specifically.
Finger crossed for the IC… 
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