shorted the heatbed
-
Hi, i'm worried that i have broken my duet2wifi.
yesterday the flexible metal plate of the bed shifted mid print and cut into the cables of the bed heater (24V), shorting it. now, when i turn on the printer the bed start heating up and is not stopping. i tried disconnecting the bed and the printer seem to work fine, but if i connect it again the problem comes back. is the board fried? or can i just switch with another bed?this is the result of m122 with bed not connected:
M122.txt -
it sounds like the bed mosfet died
it can be replaced
https://duet3d.dozuki.com/Wiki/Connector_and_spare_part_numbers#Section_Bed_Heater -
is there a guide on how to replace it?
-
this is a terrrible way to do it but gives you an idea of whats involved https://www.youtube.com/watch?v=uFev4JbVG1U
I'd add either just snip of the legs and lift the chip off when the tab joint is liquid, or use hot air, or apply low temperature solder to all joint before starting to lift it off.
(or you could just get an external mosfet and use that instead)
-
@bearer said in shorted the heatbed:
this is a terrrible way to do it but gives you an idea of whats involved https://www.youtube.com/watch?v=uFev4JbVG1U
I'd add either just snip of the legs and lift the chip off when the tab joint is liquid, or use hot air, or apply low temperature solder to all joint before starting to lift it off.
(or you could just get an external mosfet and use that instead)
do you have any reccomandations? sorry about my lack of knowledge but for this printer i put the money and my friend did the techinical work
@Veti said in shorted the heatbed:
it sounds like the bed mosfet died
it can be replaced
https://duet3d.dozuki.com/Wiki/Connector_and_spare_part_numbers#Section_Bed_Heateri have removed the board, is there some visual clue if the mosfet is really dead?
https://imgur.com/a/yc0oRka -
Unless you have a hotplate and hot air equipment, the simplest solution is to use an external mosfet instead.
-
@creepercube said in shorted the heatbed:
do you have any reccomandations?
the part in question is in between other large parts and soldered to large ground plane and large tracks of 2oz copper, so if youre not somewhat skilled with soldering or have access to proper equipment then get some else to do it, or get a external mosfet and use that.
-
@bearer said in shorted the heatbed:
@creepercube said in shorted the heatbed:
do you have any reccomandations?
the part in question is in between other large parts and soldered to large ground plane and large tracks of 2oz copper, so if youre not somewhat skilled with soldering or have access to proper equipment then get some else to do it, or get a external mosfet and use that.
sorry, i war referring to the external mosfet, if you had any reccomandations for wich one to buy
-
@creepercube said in shorted the heatbed:
any reccomandations for wich one to buy
unfortunately not, but there have been a few threads about external mosfets so if you do some searching i think you'll find what others have used at leaast.
(edit: depending on location and (lack of) urgency this might be an option ) -
This post is deleted! -
@creepercube
try your local fab labs or maker spaces. if you bring the parts and a donation you can prob make an arangement with someone that can replace a mosfet.
or take a soldering course there and ask for help during the course to do this yourself. -
@bearer said in shorted the heatbed:
@creepercube said in shorted the heatbed:
any reccomandations for wich one to buy
unfortunately not, but there have been a few threads about external mosfets so if you do some searching i think you'll find what others have used at leaast.
(edit: depending on location and (lack of) urgency this might be an option )thanks, i'll try with an external mosfet, if that does not work i'll ask for the other option. i don't want to throw away a 200€ board
-
maybe it's not the mosfet.
i placed this
(https://www.amazon.it/gp/product/B07BSBB5RN/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1)
between the bed
(https://it.aliexpress.com/item/32959212466.html?spm=a2g0s.9042311.0.0.27424c4dSYbfpZ)
and the duet, but the temperature keep increasing the same as without the external mosfet -
@creepercube you'll need to use a different output, eg another heater or a fan output
-
This post is deleted! -
Or optionally solder a wire to the gate signal to retain the configuration and remaining features.
Maybe a feature request for future revisions could be to add a (unpopulated?) header for this both to facilitate psudo-repairs and allow easy non-inverting control of external mosfets got those who need larger current than the stock board can handle.
