Accidentally shorted FAN0 :( no 5V/3.3V
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Do you see any visible marks or damage?
Does anything get hot to the touch after being powered up for only a few minutes? -
@lei261 Just a thought - but be very careful - can you connect a separate, external 5V supply and see if that powers it up? Maybe just the 5V, in the first instance, rather than a full data USB cable from your computer?
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@phaedrux Thanks for the input.
I looked around, I didn't really see any burn marks. There's only this buck converter that has something on it, a dent or scratch. I'm not sure if this qualifies for a visible damage.
After 5-10min of powering via 24V, I didn't feel anything hot with my finger, even the buck converter. I wish I had some of that "spray" thing that could immediately show you what gets hot...
I only have some 75% alcohol with me, and I'm not sure it's a good idea to spray that on the board. I've ordered some 91% IPA online, but will take some time to arrive.
I did some further measuring; if I connect the USB cable, I can measure 5V on the output side of the inductor. Since this IC doesn't have enable signal and most of the pins are connected to gnd, I'm suspecting it's the problem.
Edit: I just realized there's a DISABLE PIN, after setting Int5V jumper, I measured 0V on the Disable PIN.
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@nightowl999
Hi nightowl, Thank you for the input.
I haven't thought of a good way of doing this at the moment due to limited wiring and soldering capabilities at this moment. Had to get ride of some stuff after I moved
Really not trying to disregard your input, can you pls explain the rationale?
I was able to measure 5V on the rail after I connected USB, on the output side of the inductor after the buck converter. I mean, if I solder a 5V PSU onto the 5V rail, I think I would get the same/similiar behavior as the USB, right? -
@phaedrux
Was able to find some parts and wired up 5V and GND like below.
I was able to see 5V and 3.3V leds and the blue wifi led was also blinking. Is this how far I'd test it? Or should I do a print test with this setup? A little hesitant to do a print test because I have a "very temporary" setup. -
@lei261
My rationale was simply this: When I configured my Duet3 (MB6HC), this was done by connecting the board directly to my computer before connecting all the stepper motors, limit switches, 24V PSU, etc.There is also the ability on my board to provide a separate 5V supply, if I remove a jumper, and I think I can run two supplies (12/24V and 5V) into the same board - except nobody's really answered that question, yet. The existing Resurrect process doesn't really take account of the needs of the CNC, i.e.not saving spindle speed information. In trying to resolve that with a nested macro, there wasn't power for long enough to complete that process. I was thinking of using a second mains socket to power a powerbank, which in turn supplies the 5V to the board, but it has to be powerful enough to supply all the 3.3/5V circuitry and accessoories (whew, that was a long story, sorry).
That made me think of your situation. where if the stepdown from 12/24V is shot, you might be able to supply the 5V from a separate source, but you will need to remove the jumper so the supplies don't conflict.
Just be aware of my signature line below, before you blame me for anything, though
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@lei261 said in Accidentally shorted FAN0
no 5V/3.3V:Was able to find some parts and wired up 5V and GND like below.
Hm, kinda freestyle
This here is the recommended way:
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Yes it looks like U3 has suffered some damage and would explain the lack of 5v.
You may be able to power the board from USB connection, or from the external 5v in and still function normally. Or if you have the means, you may be able to replace U3.
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@nightowl999
Haha, and yes, after seeing ur signature, I dug really deep in my junk box and did some quick testing xD. The statement itself has some truth in it, so i will shut up and listen
I'm going to try printing with 24V and 5V USB again, maybe the error was just onetime bad luck. But in an ideal world I'd like to fix the problem. I'm currently hesitant to solder an Ext5V onto the board, as I don't have a schematic. Not sure where to solder is the best way to go for a more permanent setup....
But you raised an interesting point regarding CNC, cuz I've been thinking about building a desktop CNC for a couple years. Current plan is to do it next year
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@lei261 said in Accidentally shorted FAN0
no 5V/3.3V:I'm currently hesitant to solder an Ext5V onto the board
So would I be! Can't you use the miniUSB port (if there is one on your board)?
Having said that, if it's broken, it's broken!
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@phaedrux @nightowl999
I initially had some errors reporting with 24V and 5V USB, that's why I wanted to look deeper and fix the problem.
Now I think about it, maybe I had some other loose wires, I will reconnect everything and try again.
Thank you again for the prompt reply! -
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This post is deleted! -
Been using USB as 5V source, and printer has been printing for >20hrs without any issues. Thanks again for the advice.
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@lei261
A lucky break!Don't short anything else, you might not be so lucky next time
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@lei261 you are vary lucky not to have damaged anything. Typically, excess voltage applied to the 5V rail damages the 3.3V regulator and quite often the microcontroller and network module too. In your case the A4988 chip appears to have shorted out the 5V rail before more damage was done.
BTW Duet 3 boards (except for the Tool Board) are protected against this type of short, however other devices connected to 5V such as PanelDue are not protected and would still be likely to suffer damage.
