Power inverter repair question

Thread Starter

imaan

Joined Jul 24, 2014
17
Hi guys
I had a 300w Chinese power inverter which due to curiosity I connected it directly to my own build 160w solar panel.
But it stopped working after a while and now two red and green lights go on together .
They had used 4pcs of IRF830 MOSFETs which I replaced them
But there are 2 other MOSFETs on the other side that the place of their code has been scratched !
So can't see what number those are
Any idea how to sort it out?
Or which number is suitable for those two MOSFETs ?

Regards
 

GopherT

Joined Nov 23, 2012
8,009
Hi guys
I had a 300w Chinese power inverter which due to curiosity I connected it directly to my own build 160w solar panel.
But it stopped working after a while and now two red and green lights go on together .
They had used 4pcs of IRF830 MOSFETs which I replaced them
But there are 2 other MOSFETs on the other side that the place of their code has been scratched !
So can't see what number those are
Any idea how to sort it out?
Or which number is suitable for those two MOSFETs ?

Regards
Are they MOSFETS or double high-current diodes?
 

Thread Starter

imaan

Joined Jul 24, 2014
17
I think out of 6 MOSFET shape pcs there, 4 of them must be MOSFETs and maybe 2 others diodes
No idea , since the info of those 2 have been faded by the factory !
 

ian field

Joined Oct 27, 2012
6,536
I think out of 6 MOSFET shape pcs there, 4 of them must be MOSFETs and maybe 2 others diodes
No idea , since the info of those 2 have been faded by the factory !
There's usually 2 MOSFETs in a half-bridge configuration. In most cases anything else in TO220 or bigger is diodes, although some older PC-AT PSUs for example had one or two 3-terminal regulators on the secondary side.

You have to watch out with the rectifiers - they're very often Shottky-barrier type. When testing them, some reverse leakage is normal on the SB variety. A DMM on diode test should easily distinguish between leaky and shorted, fast silicon rectifiers shouldn't show any leakage at all.

Another thing to watch with SB rectifiers is reverse voltage rating. In AT & ATX PC PSUs, about 45V is fairly typical. Sometimes you might find them rated at 60V, but higher than that they get expensive.

If it were a flyback type PSU; SB rectifiers on the secondary side would be less likely - but not impossible.
 

#12

Joined Nov 30, 2010
18,224
Standard stuff: Please post photos and any information about brand name, model number, Users Manual, etc.
 

debe

Joined Sep 21, 2010
1,389
The 4 x IRF830 are 500v 4.5A MOSFETS, these would be in a H bridge to give the output voltage of the inverter (120V or 240V ). The other 2 IGTBs would be the LV part of the inverter (12v or 24V DC). From personal experience if you hook these inverters just to a solar panel with out a battery to stabilise the voltage. You will destroy the switching MOSFETs/IGTBs.
 
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Thread Starter

imaan

Joined Jul 24, 2014
17
Thanks for your replies
Well here is the pic of the board
I was doubtful about one of the capacitors which will change but still donno which number is suitable for those 2 diodes /mosfets
Info of the photo:
On top 4 MOSFETs irf830
Down is another one and one next to it that I've removed
Both info is being faded
 

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