L3m fan not working

[swolfp]

Hi, I have an L3m that I use as a monitor for my HD500x, the last couple of gigs I noticed it was unusually hot when I unplugged at the end of the night. I have not had any sound related issued and it was performing normally, but it was worryingly hot... I listened carefully with my ear to the fan vent and could not hear the fan running so got it home for a better look...

 

I opened the back and sure enough the fan wasn't spinning even when I let it get pretty hot again. I took the fan out and connected it to a variable power supply, and it operates as it should increasing in speed between around 5v up to 12v, so the problem is not the fan itself.

 

When I put a meter on the fan connection on the board, it measures between around 5v up to 12v depending on how hot the unit is getting, so that's also correct behaviour, however when I connect the fan to the board it straight away drops voltage at the fan to about 1.5v and the fan doesn't turn. So, it seems that the supply to the fan drops under load (no amps?). I'm no electronics engineer but I know just enough to get this far... 

 

Has anyone else experienced this or have any ideas? It's out of warranty so I've spoken to a local repair shop who have said that they would probably find a 12v source on the board and wire the fan into that so that it will be on full speed all the time... I'd obviously prefer it repaired properly so it's not always at full fan noise, but is this a reasonable solution?

 

Also I should mention that the front LED is on white, but also there is a red light on too which I assume has something to do with temperature. I know ehen the red light flashes it has something to with limiting, bu this is a steady red light together with the white light. As I said the performance of the unit has not been compromised .. I'm lucky it hasn't fried itself yet and that I noticed the problem in time!

 

Thanks for any ideas :)