Denstep board (NovaMill) shutting down after a few minutes

[Steve]

I have a customer in the USA with a problem with a NovaMill.

It has a DENSTEP control card

Is Running VR Milling 5.13.0.311

When it is first switched on it runs OK for 15 minutes or so then shuts down loosing communication.


I'm at the school with the mill issue -

I start the system and connect. The mill runs for maybe up to 10 minutes and the light on the denstep board goes out.

Attached are the messages and software version.

[Steve]

It sounds like it’s the regulator on the bottom card of the nextmove. I would try removing all the connectors other than the power in to the board.
The power is the connector to the left of the Z motor. Unplug all the other connectors including the motors.
Turn it on and wait. If it’s the regulator it will still trip out after a few mins.

As the card cools down it will reset and you will be able to run for a few minutes.
Can you check as below.
If it’s the regulator then you could try replacing it or we will have to change the whole base board.

From what you have described I would first ask the customer to:

1. Open up the control box and start the machine.
2. It sounds like the power is shutting down on the Control card so we need to know if the 7 segment display is still lit or if it goes out when the communications fail?
3. Is the fan on the control box running?
4. Is the fan filter clean?

I suspect the problem is heat related and the regulator mounted on the end of the Control card (next to the 3 stepper drive chips) is shutting down.

This could be:
1. Overheating due to failed cooling
2. Overheating due to lack of heatsink compound or not being screwed down tight to the heatsink
3. A failure of the regulator

[Steve]

The customer also had a MicroMill so the engineer tried switching Denstep cards.

I replaced the complete card system, denstep card and part it's mounted to. Mill ran 4 or 5 complete programs. Now it's shutting down again. I took the card (system) from the NovaMill and put it into the MicroMill and it's been running for a long time. Does not appear to be the card or card housing (?).

Now loosing power to card in seconds.

[Steve]

Did you try unplugging all the connectors?
If you unplug them one at a time you will then find which one allows the card to remain on. There must be something connected drawing more current than it should.

Steve
Sent from my BlackBerryR wireless device

Reply:

I did try unplugging all the connectors one at a time - it actually started working again when I had to leave. I was beginning to suspect the small connector on the bottom right side of the Denstep board. What does that connector do? The top connectors didn't seem to have any affect. It really is sporadic, sometimes turns off the board in seconds, other times I can run
4 or 5 programs. The door is open all the time on the controller.

I'll be there again next week.

[Steve]

The conector in the Bottom Right of the Denstep Card (to the Right of the power in) is the Z axis motor.

By changing out the board you seem to have isolated that part of the circuit. I do not see the motor connections causing the logic supply to shut down as the motors run off a completely different supply and there is a fuse on the card to protect them in case of overload.

I have had a few other thoughts. The control cards require a stable supply voltage Can you measure the 24V DC logic supply and the Motor power supply on the power input connector to the Denstep?

Also as you are running VR Milling 5 with the machine did you purchase just the VR Milling 5 software or did you update the top card on the Denstep? What colour is the 7 segment display.

If the Control card was upgraded and has a green display (not Red) then the card requires more power and you may have to upgrade the transformer or power supply.

Does anyone have any other suggestions before Bill revisits?