Electronic board faulty?!?

[Romano]

Hi everyone, I have a snow machine (snow falling effect, basically bubbles) that has a problem.
The machine was left on and run dry of fluid. The protection fuse gone but when I replaced it I also discovered that the fluid pump didn't work anymore.
I replaced the pump with exactly the same model (identical characteristics) and the pump works. But now I have a different problem: in theory when I switch on the snow machine, it should go on stand-by telling me "ready to snow" on the display. Then I push a button and the fan and the pump came alive and the machine starts to produce snow.
What is actually happening is that as soon as I switch on the machine everything goes on stand-by except for the pump which starts immediately to pump out the fluid. But without the other components alive (the fan) I just have fluid sprayed from the nozzle. But if I push the button activating the fan the machine produce snow. Then I push "stop" and everything should go back to stand-by, but the pump doesn't stop from pumping.
In few words as soon as I switch on the power, the pump start to work and never stops until I stop the power. Is this a board problem? Some component not telling the pump what to do? Thank you

 

[Diver300]

On a machine like that, there will be some electronics that decides when each item will run. That electronics then activates some driving device that powers the pump when required.

That driving device may be a relay or a power semiconductor of some sort.

It sounds like the driving device has failed in a way that leaves the pump running all the time. That is quite a common failure mode in power semiconductors, and is possible with relays. This is likely to have been caused by the pump seizing when it ran out of fluid.

Can you post photos of the electronics and any other devices?

 

[Romano]

Thank you very much, attached picture of the machine and the board.

How can I fixed? Bring it to someone who fix electronic boards?

 

[Diver300]

The white box is a relay. The black item screwed onto an aluminium heatsink is a semiconductor switch of some sort. I guess that one of those runs the pump and one runs the fan, but I don't know which.

To repair the board, someone will have to work out which of those feeds the pump and then try to test the semiconductor or relay to see if it has failed, and then unsolder it and fit a new one. If you have someone locally who can fix electronic boards, that would be a plan.

 

[danadak]

A well focused pic of both top and bottom of board, wires position so they do
not block view on top, pic posted as .bmp (.jpeg is compressed, eg. =
loss of some resolution).