all duex heaters shorted...
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All of a sudden all heaters on the duex5 are shorted and they blow full power as soon as I turn on the printer. I gather some 5V digital switch died... If that is the case, what else am I missing apart from the heaters? Any easy fix?
This is very frustrating...
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Has anything changed recently?
Possibly:
blown 74HCT02 chip, typically caused by over-voltage on the 5V or 3.3V rail
a failed ground connection between the Duet and DueX VIN blocks might also cause that chip to fail -
@phaedrux I had to connect via USB because wifi was acting weird. I might have done that with the main power on, could that be it? But after that I believe I printed something
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Are you saying you may have created a USB ground loop?
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@phaedrux yes, even though I was connected from a laptop
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Was the laptop on battery or wall power?
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@phaedrux battery, but that's the only thing that I did before the problem started (even though not right away).
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Well if you were on battery on the laptop there would be no path to ground through USB, so probably not a ground loop.
Can you post some photos of the board in case we can spot any burnt components?
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@phaedrux sure, thanks!
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sorry for bumping this, I would just like to understand given the symptoms if there could be anything else dead on the board apart from the heaters... should I bin the duex?
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@matt3o way too early to bin the board and if you don't find out what is going on you don't learn anything.
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@jens55 thanks
but I don't think I have the equipment (or the skill) to desolder and solder that kind of SMD components. I can do a diode, resistor, capacitor, mosfet...If it's really the 74HCT02 I don't think I can really make it
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@matt3o, there are people on here who offer 'best effort' repair services for people in your exact position. I am hoping that one of these people will pop up and offer to help.
Did you indicate your approximate location? It is only feasible if shipping costs are reasonable. -
well let's see if someone can help find the problem, visually the 74HCT02 seems totally fine and the USB connection actually works... so could be something else. I'm located in Italy, btw
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I can't see anything in the photos, but they are a tad dim. There may not be any visible damage either.
You might inquire here if you don't know of anyone local that can do SMD repair.
https://forum.duet3d.com/topic/13875/community-repairs
If you disconnect everything from the Duex except VIN do the heaters still enable immediately?
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@phaedrux said in all duex heaters shorted...:
If you disconnect everything from the Duex except VIN do the heaters still enable immediately?
damn! that was a good idea, unfortunately the heaters are still enabled (just to be clear, only the heater that is configured in the config is enabled... the LED turns on immediately)
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@matt3o, hold on a minute .... the only thing that you have going to the board is Vin and presumably ground and the only heater that powers up is the one configured in the config file ???? Something is fishy in Italy ....
This is without the ribbon cable connected between the Duet and the Duex? It should not care what is in the config file! If any heater port powers up with only Vin and ground connected then there is a hardware fault with that heater port. If only one powers up than that would seem to suggest only one defective heater output and not all of them. You should be able to configure a different (free) heater port and be off to the races ..... -
@jens55 I disconnected everything except the ribbon and power.
any heater I configure goes full throttle as soon as I give power
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Based on that, I would say that the issue is firmware related and not hardware related. I am not very good with config files but you could post your config.g and somebody who knows their stuff might be able to see something that isn't right.
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Is it all heaters or only the configured heater?
What happens when the ribbon is disconnected as well? If it's a heater mosfet that has failed closed circuit it would enable the heaters automatically.
If it's only your configured heater than perhaps the configuration is not correct. Perhaps the pin has been inverted so that it's on by default.
Please post your config.
