Posts by latelesley

TBH it could be your soldering iron too - if its old, it might not be getting hot enough. All these lead-free solders have higher melting points, and need heated for longer to melt If you're gonna be soldering frequently, I need to...

yeah, lead free solder can be a pain - infact any soldering can be a pain on premade boards - what I do if i have trouble melting the solder, is to Add some solder as I heat it, the fresh solder helps melt the existing stuff.

oh! and polarity for a coil doesn't matter its a coil no matter what way you hook it up. its Caps, Diodes, FETs/transistors, IC's you have to watch, thats when it gets important.

well, if you got the same reading, it'll be ok still! And what I was trying to say, was even if that damaged one was dead, you could have used the inductor from the dead phase, and put it on the working one. those 3 components are the...

well its kinda hard to tell with the pic's, but I think they are the inductors each one will be labelled L-something (I think the one that's off was labelled L22? ) If you measure the resistance with a multimeter on either end of each...

no, because it doesn't quite work like you think....each phase would do the powering out of step with each other, they don't all switch at the same time. in each cycle, each phase is taking a turn a 3rd of the time. so your PWM is really...

well The FETs are your main drivers (should be two per phase) and then the choke (one per phase) and then smoothing caps after the chokes. now the FETs that hook up to the phase next to U503 (on the other side of the board) I think were...

Damn! the chokes are on the other side of the board by the looks of it, as are the main drivers. The back side there, only has the PWM controller (U501), and the FET driver chips for each phase (U503, U504, U505). C565 C566 C567 may be...

They ARE in parallel - remember we worked out it was only one dead phase (I think it was the top one?) Put the two chokes back on, and take off the other one, and see if it fires up. PS Can you put up a better pic of the VRM, so i can...

well, even at 12V, the current draw is 1.62A (I took the rating of the high performance fans - it will be less for the quiet ones ) As you have the 7V resistor in place, it will draw even less, as you are adding resistance into the...