all duex heaters shorted...
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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.
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@phaedrux said in all duex heaters shorted...:
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.
I checked with a multimeter and all heaters are shorted (at the same time). I thought it was just the one configured because it's the only one that lights the LED. I tried all the heaters anyway and they all behave the same except the 2 on the duet
I'm pretty sure it's not the config because as soon as I set the heater to one on the duet2 (not the duex) everything works and the only thing that changes is the heater name. I'll try to disconnect the ribbon and also post the config just in case
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@matt3o, I am not sure if I am looking at the right schematic but what I am seeing is that the LED is connected directly to the output pin. If the output is switched low then the LED will light up. That seems at odds with the report of only one light lighting up.
Could you explain how you measure the fact that the output is shorted? -
this is all very weird and erratic.
so first time it happened I checked the heaters with a multimeter and all of them were shorted (I just check resistance @jens55 ).
I tried to disconnect the ribbon cable as @Phaedrux suggested and everything's fine, of course the duet doesn't com with the duex but the heaters are all open (off).
I reconnected the ribbon (with printer off of course) and now the heaters are all open (off) except for the one that is configured that goes in full blast as soon as I give power. In fact the heater LED turns on right away.
If I set the heater to any one on the duet2 everything works as expected.
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@matt3o, I don't know what else to suggest. From my end it sounds as if the board is fine and the issue is in the config file but as you say, it works if configured to run the heaters on the Duet.
Sorry .... -
@jens55 thanks for your help anyway, really appreciated it. I'll do some more testing but I'm out of ideas
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@matt3o what happens if you take the sd card out of the Duet, then power it all up? That way you know the config is not doing anything.
Are the outputs shorted when you don't power on the Duet & Duex? I wonder if the resistance measurement is interfering with things...
Also, what happens if you actually connect a heater to each of the outputs? Do they get hot or does the board blow fuse? Guessing it will already be blowing the fuse if it's actually shorted on the board. -
Please post your config.
