Duet maestro not connecting to DWC or being recognised by PC
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alright, ill supply 3,3v from an MCU on the output pin of the ic, is that a good idea?
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@NEVER-LUCKY said in Duet maestro not connecting to DWC or being recognised by PC:
alright, ill supply 3,3v from an MCU on the output pin of the ic, is that a good idea?
from an MCU? you can use the 3.3v from say an arduino or ftdi usb cable and connect it to a 3.3v pin on the meaestro to test - but you need to get the voltage from a power rail, not a MCU as such; and feed it to the power rail on the duet after removing or otherwise disconnecting the faulty regulator.
(and of course connect the grounds together othwerise no current will flow)
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so is it safe to connect the 3,3 and gnd form an ftdi to the gnd and 3,3 pins on the duet regulator ?
oh you said after removing the regulator
sry
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so what im thinking of doing is: i cut the IC pins all of them, and then solder the 3,3 and gnd from the ftdi on the board. is that fine ?
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The safe method is to use a current limited power supply; but yeah, I'd use an ftdi in a pinch - after - snipping off the 3.3v leg of the regulator (a flush side cutter, flush side down to the pcb so any forces isn't acting to pull up on one pad, but spread the load across all the others - but its not without risk
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@NEVER-LUCKY said in Duet maestro not connecting to DWC or being recognised by PC:
so what im thinking of doing is: i cut the IC pins all of them, and then solder the 3,3 and gnd from the ftdi on the board. is that fine ?
I'd start by just the 3.3v pin, if the it no longer gets hot the others can be left to reduce risk of damage to the board.
and yes, it'd be fine under the assumption there is no other damage to the cpu, wifi or sd card among other things.
Edit: Although you can simply use wires to connect to any pin labled ground and 3.3v on the wiring diagram to see if it works.
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Also if you have a meter, use it to measure the resistance between ground and 3.3v after taking the defective 3.3v regulator out of the equation. If there is still a short, then you'll need some serious repairs.
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wow, 3,3 and gnd seem to be connected, i did a continuity test
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3,3 supply doesnt work... instead it just gets shorted.
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I'm sorry to hear of your misfortune. I think you have a short between one of the heater wires and the hot end metalwork, possibly inside the heater cartridge. Sadly this has caused VIN to be connected to +3.3V when your +3.3V wire touched the metalwork, which has caused components powered from +3.3V to fail.
Shorts between heater wires and the hot end metalwork are not uncommon, that's why we protect the thermistor connections against shorts to VIN.
If you are unlucky, multiple components will have failed and the board will be beyond repair. If you are lucky, only one or two components will have failed. The most likely to have failed are the SD card and the W5500 Ethernet chip. So remove the SD card, then apply USB power and see if the green 3.3V LED lights up. If it doesn't, check whether the W5500 or main processor or any other chips are getting hot.
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i removed the sd card and the green led doesnt light up.
no other component gets hot.
the 3,3v regulator U2, i have cut the 3,3v pin to solder an external power source but when i measured between gnd and the pin, it was shorted and my external source got super hot, so i removed that. -
as soon as the vcc crimp of the sensor hit the hotend, the printer disconected.
the crimp didnt stay on the hotend, it just made contact for less a second and fell away from it. -
is there anything else i can try?
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you pulled the sd card and no 3.3v light
you isolated the 3.3v regulator and supplied exeternal 3.3v and no 3.3v lightthat means you have a short in one of the other chips that need 3.3v; next step is to identify which ones get hot when you feed it 3.3v and remove one by one and when no more chips are getting hot and you get a 3.3v light start putting in new chips which requires smd rework tools to both remove and install.
which as i laid out before probably means you had a short to +12/24v and that causes more damage (than a short to ground; and you really want to find and isolate that short before repairing or replacing the Duet)
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no other component gets hot... it was only the regulator, if the others dont get hot then how am i supposed to know which one i must remove?
I have no experience troubleshooting or fixing these boards nor do i have any smd rework tools.
can i send them to duet for repair?
because im not comfortable with removing and adding components, im afraid i might cause more damage than there is. -
@NEVER-LUCKY said in Duet maestro not connecting to DWC or being recognised by PC:
no other component gets hot... i
and you don't get a green 3.3v light if you apply externa 3.3v? its possible, but unlikely the led itself is damaged.
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there is a short between 3,3 and gnd, the green led doesnt light up, when i apply voltage from usb and no other component gets hot.
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If you have a short between 3.3v and ground, it would, unless using a current limtied supply, get warm when external power is applied.
And as i pointed out yesterday if you still have a short between 3.3v and ground after taking the 3.3v regulator out of the equation then at least some of the other parts will need replacing. The only reason to see which one gets warm would be to get an idea of the parts needed.
I'd take a look if anyone in this thread is near your location, or otherwise find someone with the skills and tools to assist you. there isn't much we can do online at this point.
https://forum.duet3d.com/topic/13875/community-repairs/ -
I will consider sending it to someone for repairs.
does duet themselves not repair boards? dont they have a repair service?
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dc42 has said they do*, but as he implied it could quickly be beyond (economical) repair if the fault was caused by shorting 3.3v to Vin and that does sound like the most likely cause at this point.
the reason I started the other alternative is to avoid the boards to become landfill material as the largest cost is the labour and not the parts. doesn't matter to me if I spend an hour helping you on a forum or an hour repairing a board, if I have the time I'm happy to help the community either way.
*) with covid restrictions they might not be in office to such things for a while as well.
