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I have two Tronxy 2.0 V5 Marlin boards that reboot whenever heat is applied to the bed. The bed has been swapped (because I thought that was the problem) for a new shiny one. The thermistors, too, of course. The same boards (both) work when the beds remain unheated (setpoint = 0 °C).

Any ideas what might be causing this, or what I might do to figure it out?

Note: I really have no idea which Tronxy board this is; the "2.0" is stenciled on the board, so that's all I can figure out. I shamefully admit I tagged it with Tronxy x1 to see if I could generate any interest, and because a "Tronxy" tag is not available.

Greenonline
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Peltier Cooler
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    What's the resistance of the bed and thermosensor? What is the resistance of the old bed and thermosensor? If they differ, you need to fix your firmware. – Trish May 30 '19 at 09:27
  • It might have something to do with the coefficient set in the firmware, or, similarly, the setting of the thermocouple/thermistor/thermosensor in the firmware. I vaguely recall a similar question asked in the past about the settings (but not necessarily for a Tronxy board, nor did it reset). Could you edit your question and paste in the firmware settings related to the thermocouple/thermistor? [This might help you find the related settings](https://3dprinting.stackexchange.com/questions/6849/ultimaker-original-temperature-sensor-replacement/6851#6851), but it probably doesn't fix your issue. – Greenonline May 30 '19 at 10:44
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    Can you confirm that you have a Tronxy X1? We just need the confirmation about the Tronxy X1, because if that is the case, then Mick's answer is definitely correct. I wonder if the [trony-x1] tag was only selected as it was the closest thing to what you have. There doesn't seem to be a basic [tronxy] tag. So, I'm trying to both clarify whether the tags are sufficiently diverse and whether Mick's answer is the right one (which it would seem to be). – Greenonline May 30 '19 at 12:28
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    A Tronxy X1 does not have a heated bed in stock... Also, the stock firmware does not even have heated bed enabled for the X1. Sure you have an X1 and not an x3? Voting to close **unclear** till it is cleared up. – Trish May 30 '19 at 14:44
  • @Trish, I haven't measured the thermosensors (didn't think of it), but the beds are the same and they are 12V. However, a 24V bed gives the same result: reboot. So that's three different beds. I like Mick 's idea that the PS is not up to the task; I will look into that tonight. – Peltier Cooler May 30 '19 at 17:59
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    **What kind of Printer do you use?** reboot is usually a result of too little power. – Trish May 30 '19 at 19:05
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    Can you post a photo of the printer. It should be easy enough to work it out from the photo. A [Tronxy X1](https://img.staticbg.com/thumb/large/oaupload/banggood/images/31/42/f5397ed4-41d8-4b95-a8ad-34827c93e118.jpg) has only one upright bar, the [X3 has two](https://i1.wp.com/total3dprinting.org/wp-content/uploads/2018/12/Tronxy-X3-3D-Printer-Review.png?fit=665%2C499&ssl=1). Unless, you have re-used Tronxy boards for a different printer that you have built or modded yourself - Is that the case? If so, what did the donor printer look like? Also, any serial numbers, etc. Thanks. – Greenonline May 30 '19 at 20:32
  • I'm going to go with all 12V parts (including the PSU) and see what happens. I will post results and we shall see what we see. Thanks to all for help and suggestions. – Peltier Cooler Jun 03 '19 at 21:16
  • All righty then: a 12V power supply fixes everything. Even having a 24V hot end and it still works. Thanks to everyone for helping the ignorant cope with slow learning. – Peltier Cooler Jun 05 '19 at 17:41

2 Answers2

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It sounds like a power-related problem. Always use an external MOSFET to drive a heated bed, and consider investing in a decent power supply. Inevitably, the Tronxy PSU will be barely adequate.

Edit: I've just noticed the tag. Be aware that the stock (60 Watt) PSU for the Tronxy X1 cannot power a heated bed (the printer does not have one). Trying to do so will overload the PSU and cause an immediate reset.

Greenonline
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Mick
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  • The PS is 24V 13.5A = 324 W, bit more than required, right? This is NOT Tronxy X1; there is no tag for the Tomb of the Unknown Tronxy. – Peltier Cooler May 31 '19 at 00:34
  • All righty then: a 12V power supply fixes everything. Even having a 24V hot end and it still works. Thanks to everyone for helping the ignorant cope with slow learning. – Peltier Cooler Jun 05 '19 at 15:00
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First, check the power supply. Although it may be specified to deliver the required power, it is possible that the power supply has failed in a way that it can not deliver the rated power. At lower load, the voltage may be correct, but under higher load, it either droops or cuts out completely.

To check this, use a voltmeter on the power as it enters the CPU board, not where it leaves the power supply. This accomplishes one additional check. If the voltage droops rather than cuts off, it may be that the connections have corroded and have a higher resistance.

If you have any kind of oscilloscope, I would recommend it over a simple voltmeter, because the power interruption or droop time may be very short. When the CPU resets it will switch off the load that causes the problem, and the power may quickly resume the correct value.

Second, check that there is not a short in the bed wiring. You might detect that with an ohm meter. You have used two different CPU boards, to it is unlikely to be a common fault on both boards, but you might be using the same wiring.

Third, check the routing of the bed heater wires to see that they are not near other wires which connect with the CPU, including thermistor wires and wires to the UI. High-current switching in the bed wires could be coupling into other wires and conducting a RESET signal to the CPU. Ideally, the heater wires will be twisted together with about 3 (or more) twists per inch, and not twisted together with other wires.

cmm
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  • I'm going to replace this one with a 12V PSU, and see where that takes me. I'm not really sure how I ended up with a 24V unit (a lot has happened in the last few months, and my memory is a shambles). – Peltier Cooler Jun 03 '19 at 21:14
  • Is the bed spec'ed for 12V or 24V? If 12V, then using 24V would result in the bed drawing 4 times as much power [computed as (24/12)^2] – cmm Jun 03 '19 at 21:18
  • All righty then: a 12V power supply fixes everything. Even having a 24V hot end and it still works. Thanks to everyone for helping the ignorant cope with slow learning. I'm not really sure who should get the Green Check, though. – Peltier Cooler Jun 05 '19 at 15:02
  • Great! You may be dissatisfied with the hot-end performance with a 24v heater. Did you determine if the bed rated for 12V or 24V? – cmm Jun 05 '19 at 15:17
  • The one I'm using is 12V...currently (see watt I did there?). – Peltier Cooler Jun 05 '19 at 17:40