<p>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&nbsp;&deg;C).</p>

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

<p>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.</p>

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
tronxy-x1
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.