[the_louie]

Hi!

I bought one of the nice colored tan CNEST machines with PRT-E1500W controller. After configuring it according to helpful threads in this forum I started a test run, and after a minute or two I smelled something burnt and the spindle stopped.

After opening the machine I saw what I think is a resistor that seems to be blown.


I have contacted the seller, but in the mean time I thought to see if someone else have had this problem (couldn't find anything with google search). And possible if someone have the same controller they could measure the resistor so i can replace it.

[the_louie]

I failed to include the images in the previous post. Including them here.

[joeavaerage]

Hi,
from the location on the board I would guess that is the pre-charge resistor.

When you first connect the power the power supply capacitors are discharged and there is a HUGE in-rush of current to charge them up, the
in-rush is that much it usually pops the fuse. To overcome this a resistor of commonly several hundred Ohms is inserted in the capacitor circuit
and that resistor will limit the charge current such that the fuse does not blow. After a second or so the capacitors are charged and so the resistor can be by-passed
without risk to the power supply fuse. If the pre-charge relay (or IGBT or MOSFET or SCR or whatever...) does not close after the pre-charge interval
then the drive load current will have to pass via the pre-charge resistor with the result that it burns up.

You need top establish if it is the pre-charge resistor, as I suspect and second, what device or mechanism is used to bypass the resistor....because if that
device has failed then your new resistor will last no longer than the original.

Craig