[Scrappy1]

Recently aquired a second hand 3020 mini cnc router that has no manual, and I had it running quite well until the spindle quit working. I think that I did something to the speed controller. I was doing some tests and I didn't shut down the speed control before I started it again, and it stopped working. Can someone give me some help with how to fix it?

[Scrappy1]

I am quite new to cnc and could really use some help. I have done several searches for answers, but none of the other threads have posted answers that fit my problem.
Does anyone have any ideas? Am I in the wrong forum, and if so can anyone direct me to the right one?
I got the spindle to run, and I am not sure why it ran, then it stopped again. It has been coming on and off for no apparent reason, perhaps a loose connection? The fuses are all good and I have continuity in the circuit, but it only runs sometimes?

~Grey~

[RussellK]

Without knowing exactly what machine you have, nor with any photos to go off, how can anyone possibly help?

[Scrappy1]

Thank you for your reply RussellK,

I don't know the make of this machine, it was purchased on Ebay, and the fellow that I got it from no longer has any documentation on it, and there is no identification on the machine whatsoever. Below are two photos, and as you can see, I have just swapped out the spindle for a Dremel type tool, it does work, however I would still like to get the original spindle to work.

It seems to have something to do with the potentiometer, however I can't be sure.
Any assistance would be appreciated.

Attachment 264350
Attachment 264352

Thank you,
~Grey~

[RussellK]

That's an improvement. You've got a 3020 machine with a DC spindle with manual activation and speed control. A photo showing how the wiring goes from the power supply board to the front panel would be handy - I can kind of guess, but it'd be good to know for sure.

In the second photo I'm guessing the bottom left connector goes to the potentiometer? You could unplug it and check you have the pot's resistance value across the red and black, and you got the correct range of readings between black and yellow (the wiper) and red and yellow.

If it's intermittent, it sound like it might be a physical issue, so poking or wiggling wires might be an approach, but be sure to use a non-conductive probe and keep well away from the mains.

[Scrappy1]

Thank you RussellK,

I am an artist, a craftsman, a cabinet maker, and I do CAD Design, however my electronics knowledge is still pretty primitive, so please bear with me.

If I am reading my meter correctly, it seems to be within the range that is acceptable. Across the Red and Black, I get 5.2K in the off, and 0 in the full turn mode, and respectfully, I have Blk to Yellow 0 off, and 5.2K on high, Red to Yellow reads 5.2K across the full range.

I have wiggled the wires as you suggest, and sometimes it comes on, and other times not. There doesn't seem to be a correlation for what makes it work. One time it just stopped mid cycle, and another time it stopped when I turned the pot past 3/4 of its travel, and sometimes it comes on when I do nothing.

Attachment 264472

Thank you again,

~Grey~

[RussellK]

From the sound of it, it's likely some kind of physical issue (broken wire or dodgy connection). Normally power supplies just blow up and stay that way, unless there's a heat issue where a regulator might shut down when it gets too hot, and comes on again when it cools - that's pretty special though - most will heat up until they fail.

All I can suggest is a process of elimination, as there's half a dozen points of failure. For example, you could jumper the spindle switch at the connector on the board (that eliminates the wiring to the switch and the switch itself). You could check the voltage on the spindle supply - at max speed I'm guessing it's probably 24V or something - if so you could wire 2 x 12V globes in series and connect that to the spindle connection on the board, and see if it stays lit, dims when you turn down the speed etc. That'd rule out the wiring from the board to the socket, and the plug and lead to the spindle.

[Scrappy1]

Thank you for your suggestions RussellK,
I will work on them and let you know what I find.

~Grey~