Novamill not homing

[Clive]

Fuse is OK.

This machine spends its life in my damp and cold garage and so I have given it some serious attention with a 1kw fan heater all day but to no avail.

I then donned my second best truss and shifted it into the house and parked it by a radiator.

Will let you know if this is effective.

Failing that, I guess it's a conversion to Mach3!

[Denford Admin]

From those photos it looks as though the stepper drive section on the bottom board is OK.
I guess that the issue is related to the corrosion on the top board...maybe the enable signal is not getting through to the bottom board, or the e.stop signal is not being seen by the top board. I'd pull the top board off (two screws on pillars on the left hand side then gently prise it off the two connectors)

[Clive]

I have removed the top board and there are a couple of places near the battery that don't look too good.

Pictures here:
https://www.planet-venom.co.uk/Novapics/IMG_1778.JPG
https://www.planet-venom.co.uk/Novapics/IMG_1779.JPG
https://www.planet-venom.co.uk/Novapics/IMG_1780.JPG
https://www.planet-venom.co.uk/Novapics/IMG_1781.JPG
https://www.planet-venom.co.uk/Novapics/IMG_1784.JPG
https://www.planet-venom.co.uk/Novapics/IMG_1785.JPG

They look even worse when I zoom in. (1778 and 1780)

[Denford Admin]

It does look pretty bad but I'd expect your issue to be related to the pins or circuits on the other side of the board.
The end which is corroded is all to do with RS232 communications, which I presume is working ok ? (at the moment)

All you can do is clean/repair and double check what you can (tracks, pins, connections and fuses) and if the drives still won't power up, start replacing stuff.
I think forum member AngelTech will have some spare top boards of that vintage, we probably have some bottom boards.

[Clive]

With the front board removed the back board looks in quite pristine condition, although I have noticed now that diode D25 appears to have desoldered itself at its top end.
Pictures here:
https://www.planet-venom.co.uk/Novapics/IMG_1786.JPG
https://www.planet-venom.co.uk/Novapics/IMG_1789.JPG
https://www.planet-venom.co.uk/Novapics/IMG_1790.JPG

Do I need to look at the back of the back board?

[Denford Admin]

Do I need to look at the back of the back board?

Definately get the board out and resolder that (and any others joints that look dry or cracked)

[Clive]

Definately get the board out and resolder that (and any others joints that look dry or cracked)

Well the board is off and the back looks fine.

Perhaps someone could advise how I will know when the joint has been remade correctly. From what I can see, the diode is connected to a little square patch of board at one end and a little round patch at the other. The same is true of the back, so I guess that the actual connection is made on an intermediate layer(s) that I cannot see?

Also, on the front of the board, most of the copper has vanished from the little square patch, so what is likely to happen when I apply heat and solder and do I do that at the front, the back or both?

Sorry for the idiot questions but I'm only a poor mechanical type and way out of my depth!

[Denford Admin]

It looks like a double sided board.
If you have an electrical continuity tester then just test whether the diode leg has a good 0 ohm connection to the solder pad underneath. Then check the continuity from the top leg to the next solder pad underneath,ie follow the bottom copper track to it's next destination.
I'd probably reheat the pad underneath anyway...I've seen barely visible hairline cracks around soldered pins in the past which had no connection whatsoever.
Repair of the board would be quite expensive from Baldor (in the £100's) and we have no old units we could exchange unfortunately.
If you can't get it working yourself then try a local electronic repair shop or maybe someone on here has a spare unit they would be willing to sell (try angeltech)

[Clive]

It looks like a double sided board.
................ Then check the continuity from the top leg to the next solder pad underneath,ie follow the bottom copper track to it's next destination.

That's just it. There isn't a track leading to or from either leg of the diode on either side!

Any idea what it should be connected to?

Cheers

[Denford Admin]

Sorry I don't know - we don't have access to any circuit diagrams for that board.
I can tell you that a working board here has 40ohms between that diode pin and the leftmost power input connector (the power input, orange connector below the fuse)

[Clive]

Sorry I don't know - we don't have access to any circuit diagrams for that board.
I can tell you that a working board here has 40ohms between that diode pin and the leftmost power input connector (the power input, orange connector below the fuse)

That's open circuit at the minute.

[Clive]

Just to close out this thread, sorry for the delay, I did manage to reconnect the diode by making a flat bottomed counterbore from the back of the board to a depth where an intermediate layer of copper was visible. Then I soldered a pin in the hole and soldered the diode to it.

This did nothing for the functioning of the machine.

Thanks to Angel-tech, it is now converted to Mach3, using the original servo board, after a number of faults were corrected, including a connection fault on one of the ICs.

Running well (touch wood) and nice parts being produced.

Thanks to all for your assistance.