Failed (overheated?) X2 Mini Mill

I replace the with better one try Amazon or eBay.
Even fix the broad you have it still a week

Dave
Hi all,

I screwed this thing up the other day and thought I fixed it, but evidently haven't. It's the Harbor Freight version (44991) with the regular cylindrical black motor.

I tried to hog too much steel a couple days ago, which caused what I thought was some sort of overheating protection. The machine was dead, but still getting power (good fuse, power light and exhaust fan active). I tried to let it cool a while, which didn't help, so I pulled the PCB from the rear box to check it (not quite as easy as it sounds). Nothing showed any obvious failure or signs of heat, and the solder joints looked OK. There was a forum post where someone had the main bridge rectifier fail, so I checked that and was getting no continuity (in circuit) on diode checks. I put in a beefier heatsinked one, but somehow the original read OK after I got it out (possibly poor probe contact when I checked it -my fault).

Anyway, all was well. It powered back up and I figured maybe that was it. I did a couple light tasks on it afterward, and went back to my steel dovetails tonight. After a couple decent cuts, it dies again. I wait a while and it still won't start. I give it a light Fonzarelli bump on the side of the control box and it starts, so I'm figuring maybe there's a bad connection I can look for later. I now think that brief rebirth was just coincidence, as it died again during the next couple cuts. No tapping in, or outside the two boxes changed anything, and the connections look solid. Unfortunately, I even pushed the new rectifier's heatsink into the nearby inductor and popped some sparks, so I'm hoping I didn't break anything new.

Any idea what this might be? The stalls and shutoff are clearly happening on strain, and seems likely to have started after that initial overload cut. It also has reached a point where nothing is even warm anymore, and I've popped the top off the motor and looked around, and don't see signs or smells of burning. During the brief times that it was running again, it seemed fine.

Sorry for all the text and any help is appreciated.

Thanks!

PS- I'm guessing that small red LED on the power board is supposed to be lit?
0
 
Hey Mark,

I probably won't know for (hopefully) a couple days when the parts show up. It's a prime suspect though as it was definitely burned through when I got it out. It's back on there now (minus a couple pieces of a millihenry :chunky: ). Wish I could have put something a little heavier on there knowing that the original is barely up for the task.
 
Dave,

Do you mean with a better board or better version of that choke? I was thinking a little while ago how nice it would be if some generous nerd amongst us redesigned a nicer board and had the files up for DIY.
 
I suspect that the loose choke wire was the culprit and that your board probably works now. I would STRONGLY suggest that you put the new parts aside as spares unless you really have a compelling reason to change them all out. You can only make things more complicated for yourself.
The operating phrase here is "do the minimum to get it back on the air"
Mark
 
Mark,

I would repopulate the board, but with all the warnings I saw about how fragile a couple of them were, I'd feel like they were compromised parts. The opto's in particular were a pain to desolder and were said to be highly susceptible to overheating. I was careful to protect the board and surrounding parts during removal, but didn't care much about anything I figured was getting replaced.

Take Care
 
Dave,

Do you mean with a better board or better version of that choke? I was thinking a little while ago how nice it would be if some generous nerd amongst us redesigned a nicer board and had the files up for DIY.
A new controller that is heave duty so does not go out

Dave

Sent from my SAMSUNG-SM-J320A using Tapatalk
 
It's back!!

Looks to be doing fine with the new stuff (knock on wood). I have no idea what that torque trimmer was at before, so I'll be going to look up info on how to set it later. I don't think I messed with the speed one, but I've got a cheap handheld tachometer, so I may try to calibrate the machine to my belt drive pulleys while I'm in there.

Lesson to anybody that burns one of these up- Look up under that coil before you extract anything else (wish I had). For what it's worth, the coil measured as 14mH after unrolling one winding for repair. The pins are about 16mm spacing, and the wire is 0.8mm or something in diameter (maybe 20ga). Not sure what the original specs are, as the schematics I saw simply label it as "L" with no value. This is the FC350BJ/110V board with the integrated digital circuit.

Take Care
 
Congratulations on getting it fixed!
 
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