Dirty power killed my Harman P43 - most likely parts to be broken?

[caff3in3]

So, I have an older generator and really should have been using a pure sine inverter but, I didn’t and now I have to pay for it.

I was wondering what the most likely parts to have been fried would be. I didn’t see any black marks on the PCB board but I don’t know what other parts may have blown.

When I plugged it in this morning there was a pop sound and then a bit of burning smell. I would like to confirm the culprit before buying parts to replace so I hope some of the friendly folks here can help me out.

I’ve attached a picture of the circuit board for reference

Appreciate any assistance!

 

[Mt Bob]

Did the fuse blow?

 

[gfreek]

Also fuse? I can't really see much on the board thats fried..but ...

 

[caff3in3]

Found the culprit, new board it is, the red (capacitor?) blew, sadly not just a fuse

 

[kchace]

The red part is not a cap but a MOV which is there to help stop spikes from the power line. Unfortunately if it blew like that AND the board no longer works it probably means a very large spike came in - far too large for the MOV to deal with. It’s hard to say what on the board may be blown. Certainly a part can be damaged without a “burn mark” so other that starting to replace parts it’s hard to say which one(s) are bad.

Ken

 

[kchace]

The red part is not a cap but a MOV which is there to help stop spikes from the power line. Unfortunately if it blew like that AND the board no longer works it probably means a very large spike came in - far too large for the MOV to deal with. It’s hard to say what on the board may be blown. Certainly a part can be damaged without a “burn mark” so other that starting to replace parts it’s hard to say which one(s) are bad.

Ken

You can try cutting out the blown MOV and replacing the fuse and see if it works. The MOV is not needed for the board to function. Hopefully the MOV blew and took out the fuse thereby saving the rest.

 

[Mt Bob]

Did the fuse blow? (asking again)

 

[Mt Bob]

I see you didn't reply,but will throw this out there. The MOV, in this case is a secondary board protector. If your fuse was blown, the MOV probably "blew" because the sine wave of your generator was so poor, and when it self destructed, it blew the fuse. You may be able to cut the MOV off the board, install a new fuse, and use the control board until your new one comes in.

 

[gfreek]

MOV: Metal Oxide Varistor
What is a MOV used for?
A Metal Oxide Varistor (MOV) is a protection component used in power supply circuits that is powered directly from AC mains. It is used to protect the circuit from high voltage spikes by varying its resistance

Metal Oxide Varistor (MOV)

Metal Oxide Varistor (MOV)

components101.com

 

[peakbagger]

MOVs have a fixed life, every surge takes away some capacity until they no longer conduct power.

 

[Mt Bob]

Yes,we could argue about things like voltage spikes,dirty voltage, rfi and sine wave transients, all which can affect a MOV, but generally all make it run hot,and can be like a hammer chipping away at it.
And from what I have learned, when they fail from thermal meltdown,they generally short. Which is why there is a good chance his board will still work. And the MOV could be replaced very cheaply. But, on the other hand, Harman boards really do not cost much,new.