Wrong fan, damaged printerboard

[radiorental]

I connected a 5V fan, it failed the smoke test (o;
I got wise and connected a 40mm 12V fan. It spins but wont switch off, it will vary speed a little but not much.

Reading elsewhere on this forum it seems I blew the FET that drives the fan. I'd like to replace it.

Before I go disassemble my LC to properly diagnose the part etc. Does anyone know off hand what the part number is, where the component is on the PCB?

Thanks!

[lwalkera]

Q3, Digikey PN: IRLML2060TRPBFCT-ND

[radiorental]

nice! thanks!

[linFox]

Hi there.

I feel I've done a similar thing with my fan controller on my brand new Pbot Jr. The fan I was mounting was working perfectly, but I managed to short the fan leads (doh) and now it will only run full speed.
Thing is, to ship that 44c FET from Digikey to Australia costs $34! Ouch.

Would anybody know of an alternate source for these that aren't so pricey? Thanks.

[DonaldJ]

I connected a 5V fan, it failed the smoke test (o;
I got wise and connected a 40mm 12V fan. It spins but wont switch off, it will vary speed a little but not much.

I was going to install a pair of 5v fans, wired in series, figuring that the 10v load might be close enough.

Would this pass the smoke test?

[RetireeJay]

Why would you do that? 12V fans aren't very expensive. If you want two fans, you could connect them in parallel. The 40mm fans don't draw but a fraction of the available output from the board, so two of them would still be fine.

[DonaldJ]

Why would you do that? 12V fans aren't very expensive.

It isn't the expense, it's the size.

The 5v fans are about 25mm; I was thinking about mounting one on each side of the Ubis, nice and close to the print surface.

And these little guys were actually *more* expensive than the larger fan I recently acquired. These impulse purchases at American Science & Surplus are killing me.

[hugerobots]

Don't mean to hijack this sticky, but I have a very similar issue.

My fan does still have some control over the speed when controlled in Repetier host's slider panel, but it doesn't ever turn off completely. Is this a blown FET chip as well?

(started a discussion a bit more specific here viewtopic.php?f=15&t=2847&p=19345#p19345 )

[Richy_T]

Hi there.

I feel I've done a similar thing with my fan controller on my brand new Pbot Jr. The fan I was mounting was working perfectly, but I managed to short the fan leads (doh) and now it will only run full speed.
Thing is, to ship that 44c FET from Digikey to Australia costs $34! Ouch.

Would anybody know of an alternate source for these that aren't so pricey? Thanks.

I don't know much about FETs but there's plenty on ebay in the $1-$2 range. I'd imagine that many of them would do, you just need something of a similar or better spec. Anyone know a good option? If I get time, I'll do a little research myself but it may be a while until I can get to it.

[AlexC]

If it helps anyone,. iv been running this fan on an v2 LC for a few weeks now,.. and no blown FET

P7290031_web.jpg

It moves allot of air, at about 20-25% its = to the stock PB fan and seems to work perfectly with the PB PWM for speed controlling.

100% is very strong, to strong for some bridging situations.

It is however a 40mm fan so some easy modification is required for it to attach well.

However as every bots a little different your mileage may vary,. (i don't know if older/different models had/have weaker fan FETs or not)

[FuelCell250]

I moved my fan from the side of my printer to the carriage today. I read this thread yesterday, and was being SUPER SUPER SUPER paranoid about not letting the wires short. When i was all done, somehow, somehow, one strand of wire poked through a layer of heat-shrink tubing and shorted the circuit, and it looks like it blew the FET. My ATX PSU quit instantly, and I saw smoke from the bot. I was being so paranoid about shorting it, that i willed it into existence in the form of a freak accident.

Here's a picture of the burn:

2013-09-22 21.12.30.jpg

Can anyone confirm that replacing the FET fixes the problem? Looks like it's going to cost me about $6 to replace it, and I should be able to find a friend at my hackerspace that can help me with the soldering.

[RetireeJay]

You can get a MOSFET for much less than $6 from DigiKey (although shipping may make it $6 when all is said and done). I've attached the Printrboard Bill of Materials.

[FuelCell250]

You can get a MOSFET for much less than $6 from DigiKey (although shipping may make it $6 when all is said and done). I've attached the Printrboard Bill of Materials.

Thanks! I placed the order for a new one, and this morning, I showed it to our hardware developer at work. He's pretty confident that as long as the pads didn't get burned up, he can solder the new FET on for me.

I also unplugged the fan last night and verified that everything else works. Steppers, endstops, heaters, and thermistors all checked out. I didn't mess with the fan circuit.

I'll let you all know how it works out, I'll probably check back in a week from today with results!

[chiclothe]

Would this pass the smoke test?

[Sigmoid]

Lol this is so bad! The Rev G board should feature a polyfuse on the fan wire. :/

edit: lol I found out that there IS a fuse, haha. Though apparently the MOSFET blows faster than the fuse. At least the board didn't burn. I wonder if the circuit could be easily improved to soak the excess current while the polyswitch blows, protecting the FET.

Anyway, one more FET blown. I'm browsing Mouser for a better specced alternative.

I managed to kill mine by trying the measure the voltage with a multimeter, and accidentally shorting it out. The reason for trying to measure the voltage was that after connecting a larger fan, I noticed that when the heated bed is turned on, the fan rpm drops... Now that obviously means something is underspecced for either the bed, or the fan.

When voltage starts sagging, I always start being afraid whether something on the board has found a new purpose in life as a space heater. So I wanted to compare the voltage curve on the fan pins, and on the ATX supply itself - if it's the ATX that sags, I think I can live with it, those are robust as hell.

BTW, those with shipping issues, stop trying to source the FET from the US. Find a local, Australian dealer, and get it from there. I was under the impression Digikey has a local facility in Australia, but if it doesn't, there should be some alternative. You can print out the datasheet of the FET, and take it to a brick and mortar electronics shop in your town, and ask them to give you an alternative with the same form factor and similar specs.

[Sigmoid]

By the way, the 2-pin connector on most PC fans looks nothing like the 2-pin connectors the PBot uses... The keying on the Pbot connectors is a central strut on the socket, and two vertical ridges on the connector... While on PC fan connectors, there is a little arrow-like shape.

Could someone tell me if they have names? I'd like to replace either the socket or the plug so I don't have to force the plug.

[Sigmoid]

I finally had time and managed to mod the PrintrBoard so it reliably works with a huge-ass .6A high-flow high-pressure fan. My prints improved a great lot.

http://www.printrbottalk.com/forum/viewtopic.php?f=21&t=8630

[freddy]

hello greetings from Venezuela , something similar happened to me last night , and the MOSFET under the pin the fan was burned , immediately turn off the bot, but it all works hotend is live and grow. I found these 3 types of MOSFETs in the market for Venezuela , I wonder if anyone is compatible

1) Lr024n Irfr024n Mosfet 17 Ampere 55v Smd


2) Ap4511gh


3) D3n50 500v To0252

4)BC857B


I want to know if any of these can solve the problem of burning the piece under the pin fan, exactly as shown in this post , thank you very much hope you can help me solve this situation

[RetireeJay]

Perhaps you can dig into the specifications yourself, since you found those part numbers.

Here are the things to look for electrically:
1) N-channel MOSFET
2) Current-carrying capacity of 1 amp or greater
3) Voltage (Drain to Source) withstand of 12V or greater (in practice, you will often see much higher ratings, like 60V; that's fine)
3) Switch ON with gate voltage of 2.5V or less.

Then you need to look at the physical form factor: how big it is and whether you can figure out a way to mount it and make the right connections.

[Armatus]

Will the FET from Digikey in the first reply on this topic work for new Rev-F boards? I need to replace mine.

[Mooselake]

I want to know if any of these can solve the problem of burning the piece under the pin fan, exactly as shown in this post , thank you very much hope you can help me solve this situation

You should be able to find cross reference information that will let you decide which available device will work.

Kirk