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seig SX3 dead???

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daz nosworthy30/12/2014 19:59:56
17 forum posts
Hi All, as title my seig x3 has died, came out to use as usual and nothing? Green power light is on, fuse not blown, its the electronic speed control version, no blue light on speed control, weird cos the mc was off at the estop. Blew the house trip, not the mc or plug or main plug???
Took the back off only got power on line L1 from the emi filter not N1 took the board out Abd can only see min burn mark at the 10 pin plug for the speed reader input

Totally baffled?? Any ideas?? Arc euro have new PCB but dont know where to start

Cheers, Daz
Les Jones 130/12/2014 20:37:34
2225 forum posts
153 photos

Hi Daz,
Can you confirm it is an X3 and not an SX3. The reason I ask is my X3 have a 10 pin plug on the speed control board.


daz nosworthy30/12/2014 20:57:40
17 forum posts
Hi Les, its a super X3, bought in around 07, been great generally, just built a home workshop, so its in the shed now, was thinking maybe the damp got to it, but can't fathom what's happened, how on earth can it trip the main house breaker and yet the 13amp fuse/ 10 amp mc fuse and PCB fuse be OK?? Arc says the boards can fry in sheds in the winter, but theres nothing bar the green power light
daz nosworthy30/12/2014 21:08:36
17 forum posts
Just to add, the mill was plugged in, but off at the estop at the time?? Was working on the lathe when all power went out, reset the house trip, and later went to use the mill and nothing?
Les Jones 130/12/2014 21:10:19
2225 forum posts
153 photos

Hi Daz,
I have no information on the SX3 so I can't help. I suspect the schematic for the SX3 speed control board will not be available as I had to trace the schematic fot my X3.


Nick_G30/12/2014 21:16:47
1808 forum posts
744 photos
Posted by daz nosworthy on 30/12/2014 20:57:40:
how on earth can it trip the main house breaker and yet the 13amp fuse/ 10 amp mc fuse and PCB fuse be OK??

Is the main house breaker an RCD.?

If so it will indicate that the fault lies 'probably' with some form of leakage to earth. - Most house RCD's trip around 30 mA. i.e. long before a fuse or a circuit breaker will trip.

They are designed to protect humans not delicate electronic components.


daz nosworthy30/12/2014 21:39:57
17 forum posts
Yeah RCD, but if the mill was off at the estop how could it blow thru the estop? are we thinking something shorted thru earth on the mill? Maybe blew thru the 12vand 5v boards? via earth
Took the speed control board off and no burns/melting or the speed readout the only damage on board is via the last black wire into the 10 pin connector from the speed control to the main PCB board
Nick_G30/12/2014 21:52:54
1808 forum posts
744 photos
Posted by daz nosworthy on 30/12/2014 21:39:57:
how could it blow thru the estop?

And RCD is also capable of tripping with an neutral - earth fault.

It also would matter where in the circuit the emergency stop was located. i.e. it may not simply be a mains isolator.


daz nosworthy30/12/2014 22:11:07
17 forum posts
Hi. Main power comes in via the main isolator. Then to the in line 500v 10a fuse, thru the emi filter two power wires then enter the main pcb board via the 6 way conn block L1 N1 FG U V W
L1 is showing as live now, N1 and all others dead
Looking at the connectors on the estop it looks like a low volt item to me uses 2.8 spades on the back 2 connections
Without schematics its abit of a task
Hoping Arc will have some experience of this, need to get it running again
daz nosworthy30/12/2014 22:17:29
17 forum posts
Also I swapped the board for another which was first faulty one was workin g bar a cutting out prob and nothing, so thinking all the boards may be shot..

Edited By daz nosworthy on 30/12/2014 22:17:49

daz nosworthy30/12/2014 23:48:46
17 forum posts
Just checked the estop is 250v 5a spec is on the arc site under spares
Ketan Swali31/12/2014 15:33:52
1354 forum posts
119 photos
Posted by daz nosworthy on 30/12/2014 20:57:40:
Arc says the boards can fry in sheds in the winter, but theres nothing bar the green power light

With the greatest of respect, Arc would not say this. I believe that you are mistaken

The SX3 boards for the brushless motors are far more reliable then any boards used with brushed motors.

What we could have said is that if there is a fault on a motor - especially on an X3 BRUSHED motor, it can blow a control board. We do not offer a board repair service. It is a matter of replacing the board for a new board, which could also blow if the motor has developed a fault.

I would kindly request that comments are made with some clarity, before wrong impressions and conclusions are formed.

You can call ARC on or after 5th of January to discuss the matter. A testing service is available at a cost, which you can discuss with Ian, should you wish to go down this route.

Ketan at ARC.

daz nosworthy31/12/2014 17:26:47
17 forum posts

Hi Ketan, yeah ok, I will speak to a tech and go from there..

abit of clarity..

the mc was not an Arc item, it was ordered from Axminster, the first board was replaced only a matter of months later, it was used in a dry heated workshop along with my CNC, a replacement was ordered..

that board still not working properly motor cuts out sometimes under higher loads ( 2mm+ cuts in ally) and sometimes the direction reverses, been good tho of late

so overall very unimpressed with the mill, BUT as said this was an Axminster mill not yours, Axminster have said I can buy another board to try as it now seven years old even tho its been used a handful of times...

I have now come out of my unit and just want the mill for myself to keep my hand in, as I knew of a possible issue I spoke to your guys and was told you keep the boards and that they are generally reliable ( this is an SX3..) BUT the damp can get in and cause problems in unheated sheds and was told you have a testing option for the motor as you stated, and that this would be advisable before another board, as this is already the second board

this could well be a motor fault TBH I have no idea, just wondered if any other users could advise if have suffered a similar issue, or advise if i did miss something obvious, it failed without it being on..not during use

I tried to call but you are on holiday so will try monday

regards, Daz

daz nosworthy31/12/2014 17:36:06
17 forum posts

in case you are wondering I wont deal with Axminster again, as tho its there mc the customer service was abysmal, had a hard enough job getting another board TBH, they did eventually send another board to try..BUT as with yourself was told they are 99% reliable, they could only offer to try a replacement motor if it failed again, but I would have to buy both items

maybe mine was a dud..don't know, just know it don't work

just wish I bought a good ol belt one now..

MalcB31/12/2014 18:54:15
257 forum posts
31 photos

Reading with interest, as currently looking for a milling machine and the Sieg X3 Super was high on my list until another recent price increase which now takes it to £1450 delivered.

The gaps now too close so looks as though will be opting for a belt driven VMC albeit the jury is still out on this.

As I read it, if an X3 motor develops a fault then there is a strong risk of blowing a board as well. This sounds rather an expensive occurance.

Why is there no protection between the motor and the board to stop this happening? Am I missing something here?

daz nosworthy01/01/2015 02:20:49
17 forum posts
Hi Malc, can't say they are all like mine, maybe I have been unlucky with mine, I got so fed up I bought a small prototrak mill as well, which was faultless after 6 years constant use
The SX3 is still great value if it works well and a good base for an upgrade
Again don't take my opinion on the mill or the business involved research it yourself and make your own mind up
I am speaking as a miller of over 20 years on all sorts from basic bridgeports, interacts, mazaks, multi axis and twin pallet mc's and the prototraks so I know what a good mill is, each mc has its use, I still really like the sx3 design but as you say can't understand why it's so sensitive as with mine I could be looking at ?5-600 to put it right on top of the ?1250 purchase, belts are not as easy or good looking as this but simlplicity is sometimes a blessing

Edited By daz nosworthy on 01/01/2015 02:21:33

Les Jones 101/01/2015 09:21:31
2225 forum posts
153 photos

Hi Malc & others,
The motor and controller are totaly different between the X3 and SX3. The X3 uses a permanent magnet brush motor with the speed controller using phase angle control via SCR's to control the speed of the motor. I have traced the schematic of this controller and the information is on my website More information about a motor failure on my mill is in the file section of the "Yahoo X_Series_Mills" forum. (You may have to join the forum to get to the file section.) The SX3 uses brushless DC motor which does not have a commutator. The speed controller board will be totally different for this type of motor. I have not seen one of these boards or a schematic so I can only guess at the design. I SUSPECT that the basic DC supply is derived directly from rectified mains. This means that a short or leakage to earth on any part of this board or on the motor will cause the RCD to trip.


Ketan Swali01/01/2015 09:33:43
1354 forum posts
119 photos

An X3 is a 600w DC brushed motor machine with a belt and gear combination drive.

A Super X3 - SX3 in short is 1000w brushless motor machine with a belt drive.


The brushed motor on the X3 hangs on the outside of the machine. If you have a cold and/or damp workshop, the early models of the X3 used to get effected, especially if machines were left un-used. This problem is not unique to this machine. I am no electronics expert. All I know is that warmer workshops, combined with starting the machine at slow speed for such motors, to warm them up, before use in a cold workshop, or if the machine has not been used for a long time, could help in avoiding damaging circuit boards. After the first two/three years of manufacture of X3, the newer brushed motors on the X3 have proved to be more stable if machines were not used. However, the principal as stated still applies to almost ALL hobby class brushed DC motor based machines from China. Concept: ‘Use them or lose them’.


Why a fault in the motor could take out component on a circuit board, again i have no idea. Perhaps Les can comment on this. He is one of the people on this forum who does have extensive knowledge of the original X3 board.


Now, coming onto the SX3. This has a 1000w brushless motor, which is a totally different animal. It is enclosed inside the head. In the early days, this machine had issues with torque due to the incorrect programming on the related control board. ARC only started selling the SX3 after the torque issue was addressed. All of this is well documents across forums. It is quiet because of the belt drive, and in terms of torque, in ARCs opinion, it is capable of successfully taking on any machine in this size/capacity.


When comparing, you need to compare with other hobby machines in this size, gear or belt drive. In terms of torque, the 1000w brushless SX3 will challenge a 1200w to 1300w brushed DC machine in this class - with or without belt drive, and ARC is happy to make this non-bullcrap statement. I don’t know if it can take on the three phase motor with inverter new offerings on the market by a competitor, but in terms of torque across the speed range - low through to high, I am quietly confidant that it will, and it is at a cheaper price.


Why Daz has been unlucky on two occasions with his Axminster SX3 - I don’t know. I stand by my statement that the brushless motor with related control board is very much a robust system. When we first started selling the machine, SIEG told me that it is suitable for light industrial use, in other words - semi-continous use. Visitors to our website, as well as industrial users who have bought this machine from us over the years, are very well aware that we only sold this machine for hobby use, until middle of last year - 2014. Also, when we sold the SX3 to industrial/business users, we sold it without warranty or guarantee - totally within the law before anyone decides to challenge this comment - as it was sold for hobby use only. We only revised our statement for this machine to hobby and light-industrial use later last year, after observing the performance of the machine through sales and service/electrical compost low failure over nearly four years.


We have not changed the statement from hobby to light-industrial for any other machine which we sell. The key reason is, industrial users buy the hobby machines as a cheap solution. Some of them understand the limitations, and some don’t. Many of them have years of experience and they also have bridgeports on their asset register, but they don’t compare an SX3 to a Bridgeport. I am not having a go at Daz here, so Daz please don’t feel offended


As I said earlier, I don’t know why Daz has been unlucky with his Axminster SX3. It is generally not so sensitive. In fact, this system is far more superior in terms of electronics then most in this size. Daz can call and discuss with me on Monday if he wants to.




Happy New Year


Edited By JasonB on 01/01/2015 13:09:03

Ketan Swali01/01/2015 09:37:25
1354 forum posts
119 photos

Continued from post above. (JasonB)


Malc., in terms of price, it looks like you missed out on several offers during 2014. If you are still interested in 2015, and if you can wait, perhaps you might be able to take advantage of the offers this year as and when they come about, that is if you are still looking to purchase an SX3 at the time. Otherwise, there is plenty to choose from out there, including VMC which is far more metal/heavy duty, and/or good/bad ol iron ….Every machine has its place, size, price and a workshop home in life.



Thank you, it looks like you beat me to it with a response.

Ketan at ARC

Edited By JasonB on 01/01/2015 13:10:48

Les Jones 101/01/2015 10:54:22
2225 forum posts
153 photos

Hi Ketan,
I suspected your original comments to Daz had been based on you being told that the problem was with an X3 as it was described in Daz's original post rather than the SX3. The reason that motor failures can damage or destroy controller boards is that fuses between the controller and the motor would not be fast enough to protect the semiconducter power devices on the controller board.
I have now put the information about the motor failure on my X3 in 2008 on my "Weebly website" as I have run out of space on my "Tiscali website."


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