FAN0 and FAN2 not working

pipersw

I have a Duet 2 Wifi 1.04 since few month. I have a blower fan on FAN0 and a extruder fan on FAN1 and at the begining all work good.
A time ago I remove and replug the fans, but the two are inverted. So I reverse the plug.
I have replace the faulty fuse fan blade, and now the extruder fan work on FAN1 and Always On plug, but don't work on FAN0 and FAN2 (with M106 P0 H-1 S255 for FAN0).
The blower fan don't work on any fan plug.

I have to change the two MOSFET for FAN0 and FAN 2 ?
I have a hot air station.

pipersw

A wire on blower fan disconnected. After resoldering the fan work on fan1, but not on fan0 and fan1. I wait for new mosfet

dc42

I'm glad you found the problem.

When removing the old mosfets, you need to either shield the white plastic parts of the fan connectors from the hot air, or remove them temporarily. Otherwise the hot air will burn them. I heat them to 170C using hot air and then pull them off using pliers. After replacing and testing the mosfets, I heat the pins to 170C again and put the plastic parts back on.

pipersw

I could put a PMV20XNE 7A for mosfet. It could be more stronger.

dc42

@pipersw said in FAN0 and FAN2 not working:

I could put a PMV20XNE 7A for mosfet. It could be more stronger.

A quick glance of the datasheet suggests to me that PMV20XNE would indeed be a suitable replacement, with a higher maximum drain current.

pipersw

Do you know why the mosfet for the fan are more subject to fail ? Current spike with inductance ?

dc42

In typical use the fan mosfets are reliable. However, if a fan output is shorted, or the fan is connected the wrong way round, then a high current flows and the mosfet typically fails before the 1A fan fuse blows. Also, if a DC motor is connected to a fan output, then the starting current of the DC motor is typically higher than the 3.5A current rating of the mosfet. The mosfet may last for a while, but eventually fails.

Brushless fans don't generate current spikes, and in any case revision 1.02 and later Duets have flyback diodes on board.

pipersw

@dc42 said in FAN0 and FAN2 not working:

PMV20XNE

after change mosfet for the 3 fans with PMV20XNE, all work now !!

dc42

@pipersw, I'm glad you got it working. We're looking at changing the fan mosfet type to AO3400A or PMV20NXER in future production runs.

mitch

@dc42

Well, I messed up and I think I need to replace some MOSFETS for Fans1 and 2.

I was trying to connect a 3 wire part cooling fan and I accidently shorted the GND of the 3 wire fan to the PWM GND of Fan1 and I saw a little smoke come out of the new 3 wire fan.

To try to determine what exactly I broke. I tested the fan fuse and it is fine.
I took a known good fan and connected it one at a time to
Fan0, used the M106 P0 S1 command and it turned on
Fan1, used the M106 P1 S1 command and it wouldn't turn on
Fan2, used the M106 P2 S1 command and it wouldn't turn on

I saw this post where you indicated that the MOSFET most likely went out.

Am I correct to assume that means that I need to replace MOSFETs for both Fan1 and Fan2 with PMV20XNE?

I have a hot air station but I wouldn't say I am great at it. I could use some recommendations on temps for removing the existing part and putting the new one on.

Thanks in advance.