Author Topic: Sieg Micro mill problem.  (Read 738 times)

Offline DavidA

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Sieg Micro mill problem.
« on: September 02, 2019, 04:36:15 PM »
Hi all,

Haven't been around much recently, but as the winter is approaching it is time to go in the shed, turn up the heat and make progress with the Fowler 4f loco.

So, I was machining a small block of aluminium on the Sieg. Switched it off, but it wouldn't re start.

It has been doing this on a number of occasions. It is running ok. Turn off the motor with the speed control, and when I try to start it again, nothing happens.

The green light is on.

I have checked the brushes, ok.

Looked inside the electronics box. no sign of any loose connections or burning etc.

I have had the machine for about five years, but it is very low mileage. Probably hasn't run for more than twenty/twenty five hours total. All very light work.

(I did notice that the motor pinion is an absolutely abysmal fit on the shaft. I'll have to do something about that)

Does anyone know what may be causing this problem ?  Is it a 'stock' fault with these machines ?

Hope someone can help here.

Dave.

Offline Barabas

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Re: Sieg Micro mill problem.
« Reply #1 on: September 02, 2019, 06:16:34 PM »
I'd guess the switch on the speed control is duff.  That's what happened to mine - sometimes a light tap with a small hammer on the knob would make it work for a while.  A new pot from arceuro fixed it - not too difficult if you're handy with a soldering iron...

Offline DavidA

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Re: Sieg Micro mill problem.
« Reply #2 on: September 02, 2019, 07:39:22 PM »
Thanks for that.

I'll try pulling out the pot and maybe I can effect a temporary fix. If that works then I can get a new one.

Dave.

Offline RodW

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Re: Sieg Micro mill problem.
« Reply #3 on: September 03, 2019, 07:57:27 AM »
Try removing all connectors, spray with Inox and wipe clean then reassemble. Worked a treat on my Seig SX3
RodW
Brisbane, Australia

Offline John Rudd

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Re: Sieg Micro mill problem.
« Reply #4 on: September 03, 2019, 08:34:20 AM »
Before you dive in pulling things apart and condemning parts, try this first!

Disconnect the motor wires where they connect either to the main pcb or the fwd/rev switch. Now take a domestic light bulb in a holder with a pair of wires attached...Connect in place of the motor.
Now set the mill going as you would, the bulb should glow from dim to full brightness as the speed pot is operated.If it does then suspect the motor, if it doesnt behave like this then the fault is with the electronics...
Report back your findings and we will take it from there....
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Offline DavidA

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Re: Sieg Micro mill problem.
« Reply #5 on: September 03, 2019, 05:25:39 PM »
 thanks.

There does appear to be a problem with the pot.Rather the switch on the pot, the pot checks out ok.

I was just looking at the Arceuro Trading page on the parts.

It seems there are two different switches. depending upon the board.

One switch has open contacts when it is turned to the 'off' position i.e fully anti-clockwise.

The other has closed contacts in this situation.

My switch has open contacts in both 'on' and 'off' positions.

I noticed that the wires from the switch go directly to the lower two pins on the green connector strip (z1 and z2) if I remember correctly).

So I linked these two terminal to simulate a closed switch.

And what happened was I got the yellow 'Unnormal' operation light. Plus the green power light.

So, tomorrow, before removing the board (the ID appears to be on the bottom side) I'll just try it with the link disconnected. If it fires up then I know which version it is.

I don't suppose anyone knows if the switch is a dead short when the contacts are closed, or is there some resistance. i.e built in resistor inside the riveted shut switch body ?

I'll get back tomorrow with an update.

Dave.

Offline John Rudd

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Re: Sieg Micro mill problem.
« Reply #6 on: September 04, 2019, 01:51:21 PM »
A better clue to which switch is needed, is the number from the speed control board..an XM number perhaps?

Ordinarily, the speed control pot has the contacts arranged such that at minimum speed the control switch is open and then goes closed when advanced...as described by your comment it would appear that the inverse causes the fault light to come on....
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Offline DavidA

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Re: Sieg Micro mill problem.
« Reply #7 on: September 04, 2019, 04:19:18 PM »
 John,

I ordered a new pot/switch today. The board is an XMT-2315.

So In a couple of days (hopefully) I will be able to see if it is that or a new board.

I was surprised, to put it mildly, at how badly the motor pinion is mounted. Not surprised that people finish up with wrecked gears.

Dave.

Offline DavidA

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Re: Sieg Micro mill problem.
« Reply #8 on: September 06, 2019, 04:39:48 PM »
 The switch arrived this afternoon.

Half an hour later the machine was running again.

Thanks for all the advice on this problem.

Dave. :thumbup:

Offline John Rudd

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Re: Sieg Micro mill problem.
« Reply #9 on: September 07, 2019, 05:27:43 AM »
Good to hear you got it sorted and working again
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr