Duet2 Wifi fan runs constantly

Phaedrux

I fear that you may have fried a mosfet or something with the previous wiring setup so that Fan1 is failed in the on position.

Connect a fan to the Fan1 port
Send M950 F1 C"fan1" followed by M106 P1 S1 and M106 P1 S0

is it able to control the fan?

cdthomas9

No joy on that, I also tried this for fan2 as well, no control for any fan PWM channel it seems. I haven't had this board long at all either.

fcwilt

@cdthomas9 said in Duet2 Wifi fan runs constantly:

No joy on that, I also tried this for fan2 as well, no control for any fan PWM channel it seems. I haven't had this board long at all either.

Well if you had both convertors connected and applied power you may have fried both fan mosfets.

Frederick

cdthomas9

Why would that happen? Do they draw too much current? Just operating a fan?

cdthomas9

And if that's what happened how can I fix it?

fcwilt

@cdthomas9 said in Duet2 Wifi fan runs constantly:

Why would that happen? Do they draw too much current? Just operating a fan?

I don't know that specifics of your convertor so I cannot be sure.

I once connected a small incandescent bulb to a fan output. It's rated current was well within the capabilities of the fan output.

What I didn't account for was the large inrush current that is a characteristic of a cold incandescent bulbs. That inrush was enough to instantly destroy the MOSFET driving the fan output.

Perhaps your convertor also has a large inrush current.

Frederick

cdthomas9

Ah, yeah that makes sense. I wasn't thinking about that, that's probably exactly what happened, thanks.

Phaedrux

@cdthomas9 said in Duet2 Wifi fan runs constantly:

Why would that happen? Do they draw too much current? Just operating a fan?

I'm not savvy enough to answer that either. But at least it failed ON and instead of OFF. Could be used as the hotend heatsink fan at least.

The mosfets can be replaced if you have the tools and skills.

https://duet3d.dozuki.com/Wiki/Connector_and_spare_part_numbers#Section_Fan_mosfet

cdthomas9

Thanks, I'm going to order a new board, and the parts to try to fix this one. I have the tools needed but I've never done any SMD work so this will be a learning experience

Phaedrux

Good luck! If you do a search in the forum you can probably find some good threads for tips.

Veti

@cdthomas9 said in Duet2 Wifi fan runs constantly:

Thanks, I'm going to order a new board,

if you are ordering a new board. consider the mini 5 or duet 3

cdthomas9

I had already ordered a replacement Duet2. The 3 seems overkill for this little printer, and I hadn't even considered the Mini 5, I actually had never read anything about that board at all. I would go for it but no one sells it.