Repairing a Pure Sine wave inverter 1200 - 2400W (Moonraker Brand)

Thread Starter

Matt Dyzio

Joined May 24, 2017
8
Hi Guys, I am new on here trying to find some help and guidance. Got this inverter for £50 but its more then fuses thats wrong with it.

I opened it up and i saw all the fuses (Labeled 2 on photo) they were all soldered together ie shorted. So i cleaned it up a bit and removed all the fuses. for now i just put a bit of wire there. Also a track was broken and I saw someone already butchered or tried fixing it (3 on photo).

Also the whole board looks smothered with something tacky, maybe its flux ????

Also (Labelled 1 ) the transformer core (the metal square bit on top) is loose, i can move it from side to side about a 1-2 mm.

I would also like to warn all the users that I am a bit of a electronic engineering idiot. I try to do a lot and learn it but compare to most of you guys, I know nothing.

I have most tools and access to an oscilloscope.


I would be really grateful if someone took some time and maybe gave me some hints, it would really be appreciated and I thank you in advance for doing so my friend.

When I was buying this I thought it was just the matter of changing the fuses and off i went but, it appears someone shorted the fuses and pushed the poor little sucker too far. And now something bigger went.

Also i probed around it with multi meter when plugged in to a 12v SLA. I saw some 460V and I have no idea what I am doing.

AGAIN THANKS FOR READING.

Im hoping to document most steps undertaken while fixing this.
 

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Thread Starter

Matt Dyzio

Joined May 24, 2017
8
Also i think i fried it even more, poking around with meter in diode mode. I tested a pin coming from the "PIC IC PCB" with a mosfet and it wend spark and started going beep beep the alarm on the inverter did anyway. I am slapping myself against the head, feel like such an idiot. now the fans are on constantly, but dont think i am getting any 480 V DC anymore :(
 

dendad

Joined Feb 20, 2016
4,503
You are playing with a potentially lethal box of tricks there so please be very careful.
What is it's type/model number and do you have a circuit for it?
It does sound like you may have killed it. It the PIC is dead, you may have a paper weight there.

The transistor??? near the orange capacitor in picture 1408 looks odd. Is it just covered with stuff or burnt?

You MAY be able to grow something like this in..
http://www.ebay.com.au/itm/DC-AC-Pu...536970?hash=item465a4a6a0a:g:X80AAOSwcUBYS8EY

Often these inverters have a DC to DC step up from battery Volts to a DC voltage that will be the peak volts of the required AC volts.
Then the DC is fed to a "H" bridge to generate the AC.
I would have thought the 480V should have been more like 340V. That is the peak of 240VAC.
Maybe the regulation on that DC to DC converter stage was dead and caused over voltage to pop the H bridge and therefor the fuses?
First off, with NO POWER ON!!! measure the resistance across the FETs in the H bridge to ensure there are no shorts.
There will be a reason for the popping :0
You need to find that first. If you can get it going again, try running it without a load, with a headlight lamp (of the battery voltage) in place of the battery fuses. This will protect the circuit and usually still let it run enough for debugging, but not at power.
NEVER replace fuses with wire! Then all that happens is something else pops instead of the fuse!
 
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Thread Starter

Matt Dyzio

Joined May 24, 2017
8
Thanks for your reply dendad

I know its dangerous, I am very careful. Thank you for your concern. The pic might not be dead, i might of just broke something on it. I say this because, when I was first trying to test it the fan marked (1) in this pic IMG_1479e.jpg, turned itself on for a brief second and then turned off. But after the "incident", the alarm now just beeps, and the fan marked (2) is on constantly. So i might have destroyed the driver board but optimistically thinking i might have just broke something else and now the board is giving me an alarm due to something else. If we find the schematic I might be able to wire a replacement driver board into this thing, if that's whats wrong with it and get it going. If not I would love to know how to build them from scratch. Using the components here and maybe some replacement parts.


Is this what you are referring to?IMG_1480w.jpg That is just flux like stuff that's all over everything.

As far as the fuses. When it arrived i opened it up and noticed where the fuses were, the space between the two legs underneath the circuit board, where the current passed from one big pad through the fuse to the one next to it, It was all soldered together with even some copper cable in between.
I reckon the fuses where blowing and someone did that trick. And consequently blew something else on the board. So instead of fuses i just put a bit of wire there, only one thin wire. If you think i should replace it with one of the 5x 30Amp fuses that where there instead? or try to stick all 5 in there, couple of them no longer viable (would need to order some). OR HEADLAMP?


here is a pic of what i have done and the 2 of 5 fuses that i fished out of the bin.IMG_1499[1].jpg


I measured some fets.

the h bridge has 2 of these (http://pdf.datasheetcatalog.com/datasheet/fairchild/IRFP460.pdf)

and 2 of these other ones i cannot find the data sheet for. here is a picIMG_1500[1].jpg <=- These two are shorted. I tested for shorts and all these legs are 0 Ω resistance


IMG_1501[1].jpg
here is what one side looks like the red dots are shorts.

On the other side looks like this IMG_1504[1].jpg

ALL RED DOTS ARE SHORTS.

Again thanks for your feedback and thank you for your time.

I gotta admit yesterday I lost my cool with this thing and almost listed it back on ebay. I felt so stressed out due to not being educated in these things.

But I am not giving up. <=--- PERSEVERANCE IS THE KEY TO SUCCESS

I reckon with the support from you guys and your guidance, I will get somewhere. Again I want to know how these things work and would love to get some guidance, i am doing a bit of reading but so busy working.

Thanks again dendad

:)
 

dendad

Joined Feb 20, 2016
4,503
That does seem to be a lot of fuses.
Anyhow, the headlight lamp , just put it in the 12V power line externally, just for testing. It will limit the current to a safe value and usually will pass enough to have the unit run as long as there is no load on the inverter. The standby current of an amp or so would keep the lamp cold so it will be low resistance and not drop to many volts. But if the current increases too muh, the lamp heats up and it's resistance will go up and drop more volts. It is an old trick and a very handy one. In fact, I have a 24V test power supply that has a 24V headlight lamp,with a buzzer across it for good measure, set up for fixing dead equipment, and many times it has lit up with a beep to save me from smoking things further.
Is this the other part?
http://www.st.com/content/ccc/resou...df/jcr:content/translations/en.CD00077683.pdf

It is worth pulling all the FETs/transistors out and measuring for shorts. And check all the diodes too.
As an exercise, you could also have a go at tracing the circuit out. That often helps understand hoe things work.
 

Thread Starter

Matt Dyzio

Joined May 24, 2017
8
Thanks a lot. I got a go out tonight and probably be a bit hung over tomorrow. But might get them out this weekend and measure them.

As far as sketching out the circuit diagram, any good software out there, that maybe lays it out for you automatically.

Have good weekend everyone!!!
 

Thread Starter

Matt Dyzio

Joined May 24, 2017
8

MrAl

Joined Jun 17, 2014
11,708
Hi,

Here's an idea: buy a new one :)

Seriously though, you are daring a dinner with death here. Converters can be dangerous, more than you might think because there are many ways in which they can cause severe injury. I'll try to mention a few here.

For one, there are dangerous voltages, which you probably already know, but that's not the end of it by any means.
When some parts blow they cause other parts to blow due to some parameter going too high, and that can easily cause the part to actually explode like a bomb. Note i said bomb, not fire cracker.

Transistors can blow hot metal and plastic in all directions.
Electrolytic caps can explode in various directions depending on how they are made.

I've seen things like this explode and it's not pretty.

Now a look on the practical side...

Very often when these things blow out they take out parts that are hard to replace. If you get lucky you can replace some parts and get it working again, but if any of those parts can not be replaced then you cant fix it anyway.

It's up to you of course if you want to continue, but caution is the main word here. Eye protection, even body protection, is a good idea at the very least, as well as care when making measurements.

Good luck with it :)
 

Thread Starter

Matt Dyzio

Joined May 24, 2017
8
Thanks, I can Replace all parts if not just rebuild it using the components. Buy a pcb from china! and build! But its all Good thanks for the concern yet again.
I have a hot air station and i can pop parts out easily!!

Just need guidance, I am careful. I just probe with meter, caps don't hold anything at the moment because there are shorts somewhere eating the power.

Thanks Guys I will follow up with some stuff once i get somewhere
 
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