Hi Brett,
Can you post a picture of the control panel of your mill? I have a SX1LP (from ArcEuro Trade) and your description does not match mine. Mine has a brushless DC motor with feedback which won’t run when connected to a DC supply like a car battery.
Maybe yours is an earlier version.
If you are anywhere near Cambridge I’d be happy to come and have a look at it. I’m an electrinics engineer.
If there is a circuit in you manual can you post a copy of that too?

Robert.

Hi Brett,

I don’t see in the description above that you have checked the fuse – in the circuit Robert found the power light will still come on even if the fuse has blown.

Keith

Does it have any micro switches on it anywhere? Like on the safety guard?

I agree that the reversing switch is a likely suspect, but, in the event swapping it doesn’t fix the problem, we can try a methodical analysis.

Though it can be done without a multimeter, I recommend buying one. A cheap digital meter will do, this example from Amazon, other meters and vendors available.   A meter is aafer and less error prone than messing about with light-bulbs and car-batteries!

On the subject of safety, some tests are done on live equipment so be careful not to put self in contact with anything.   In the diagram terminals marked in GREEN are low-voltage safe; and those in RED are high-voltage dangerous.   Box C is AMBER because I don’t know!  Probably low, might be high, so approach with caution.

I’ve annotated Robert’s diagram to show where to test:

Before starting, confirm the board is wired as per diagram.  Mistakes, loose wires etc will stop it working: everything has to be right.   (Within reason, substituting a 4k7 pot for 5k is OK!)  Don’t assume things are OK just because they look right – do the electrical test.

With the mill unplugged from the mains.

1. Set multimeter to ohms and test terminals K3 and K4 really are connected together by the strap shown in Green Box A.  The meter should read zero ohms.
2. Set multimeter to read ohms about 5k.  Connect probes between terminals P1 and P2 (Green box B).   Then turn the speed control pot: the ohms reading should vary between zero and 5000 ohms.
3. Now connect probes between terminals P2 and P3 (Green box B).   Again turn the speed control pot: the ohms reading should vary between zero and 5000 ohms.
4. Still on ohms, move probes to terminals K1 and K2 (Amber Box C)   Turn the speed control pot so that it’s ON/OFF switch operates.   The meter should read zero ohms when switched ON and infinity (1) when OFF

The controller will not work unless all the tests above pass:

• K3/K4 are for the emergency stop.  Although this particular mill doesn’t have any e-stops, the terminals must be closed by a strap.
• The pot controls speed by applying a varying voltage to terminal P2.  The controller won’t work unless the pot is working and correctly connected.
• K1 and K2 turn the motor ON/OFF.  No power is output to the motor unless the pot switch is working and properly connected.

With the mill plugged in and turned ON.  (CAUTION: shock hazard!)

1. Set meter to an AC volts range suitable for measuring 240Vac.   Probe terminals Line 1 and Line 2 (RED ellipse D) to confirm power is reaching the board.    If not check fuse with ohms range and wiring.
2. Set meter to a DC range suitable for measuring 200Vdc.   Set the pot to mid-range and probe terminals DC+ and DC- (RED box E).  This should confirm the board is supplying power.
3. Next set the Forward/Off/Reverse switch to Forward and DC probe the motor (RED box  F) to confirm that power is reaching the motor.   May be difficult to probe the motor, might be easier to connect to the output tags on the F/O/R switch.   Operate the switch to confirm it goes OFF and then reverses.

Mechanically minded chaps like to believe that electronics are less reliable than mechanical objects.  Not so!  The main cause of electronic failures are mechanical:  worn switch contacts, corrosion, cracked tracks, loose connections, frayed insulation, dry solder joints etc.  Unfortunately, mechanical failures can stress the electronics to destruction – they’re only reliable within their design operating range.   F/O/R switches are quite complicated and may be too cheaply made! If one goes wrong, mains may not get to the board, and/or DC may not get to the motor.   A meter is the best way of testing it, but they’re cheap enough to replace on suspicion.

Dave

Don’t feel too bad.
Something blew the fuse. Likely the control board and possibly the motor failed first and damaged that.

Robert.