I have a problem with my print head refusing to cool the hot end while printing. The fan does nothing. I’ve tried two different replacement fans and the fan itself is not the issue. Print cooling fan works fine and so does everything else. I am inexperienced in testing the board connections, can I get some advice on how to proceed?
I’ve tried gcode commands to heat up to 200 to trigger the fan and observed it while trying to print with the print head sides off, without success.
Hey!
Do you have a Multimeter at home?
I can get one, but I’ve never used one before. If you describe what I should do I can probably get help from a friend to execute it. We’re basically going to check the 2 pin connection on the board, right?
I would check the contacts of the cable after you unpluged it from the board. I noticed on my printhead that one cable was unplugged of the connector. Maybe you got the same issue…
Anyway, with a multimeter you could check if there is an electric circuit / flow.
I think you have some issues with the contacts.
If you need, I can send you some photos.
I currently have the entire hot end disassembled so there are just a bunch of lovely parts dangling from where the board is hanging above the print bed, so I can see what is and is not connected and check connections pretty easily. I can double check deeper inside the plastic connector to see if the tines are touching, if that’s what you’re suggesting. I’ll have an update tomorrow or Friday once I borrow the multimeter.
Yes, please check the contacts inside the plastic connector. With the multimeter is pretty easy to find out if there is a electric circuit or not.
I did this with the help of several different engineers of different disciplines. The issue relates to a repair I did on the print-head several months ago-- apparently the JST connectors used by the stock fans that come with the snapmaker have their polarity inverted-- the red and black wires for the fans are the reverse of whatever the global standard is. I, not knowing that, plugged in an otherwise identical hot end fan when mine gave out earlier in summer and failed to notice if it wasn’t working.
The oddity here is I was able to make a lot of successful prints since between then and when I noticed the fan wasn’t spinning, but it seems impossible that it could have been working before as the fix was to take the red and black wires out of the JST connector and reverse them to match the snapmaker original fans.
Why would they design it this way? A room full of very well educated people could not think of a reason other than to frustrate customers.
Where are you from? I heard about that Americans also had some electrical things which are the opposite to Europe.
I’m from the US. I bought my A350 from a Micro Center (fantastic big box retailer) in Ohio from the first batch of A350s sold in stores. I have 20+ different fans of various sizes and voltages for electronics in my workshop and I’ve never seen this kind of two pin connector with the polarity reversed on the board and the connected fans.
Are you saying this only happens on some models?
@TheIvoryDisaster
No I don’t want to say that some machines are wired different to other ones. But I think there is an different electric standard between the rest of the world and America 
I don’t know why… it seems it is something like inch and meter, liter and gallon 