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  1. #21
    I'd tread carefully here with blindly replacing boards - the problem is not (as I understand it) known to be with that card at this time. That is what OP is asking about and unfortunately I don't know enough about that card to understand the protocol between itself and the (modified) spindle control card in the mill (the same kit, even if OEM with SIEG, requires a modified micro controller on the spindle control card).

    This link provides a really interesting bit of reverse engineering which explains a bit about the protocol used on the "LMS" board (aka Sieg board).


    I'm about to head to my SX2.7 and see if this is similar to the touch-panel interface (nothing is ever that easy! and I fear the LMS interface will be different)

  2. #22
    Here's an update to the no spindle rotation problem. Yes I've seen the Little Machine Shop's upgrade and now realised that this is an alternate board used by Seig to enable the speed to be altered by the BOB output. I have been in contact with Arturo at CNC4PC and he suggested that I check the wiring of the actuation circuit as everything else checked out OK. This consists of the mains feed passing through a small transformer on the AP2 board and is switched by the relay on the BOB. On investigation I found that I was not getting any mains voltage at the input to the relay in any position. Mains was found at one of the pins going to the transformer. Checking the primary of the transformer for continuity through the transformer I found that it fails( No Continuity) Followed the tracks to the transformer and when tested these were OK to the pins. The secondary circuit tested OK. That's my problem - burnt out primary winding on the transformer. The relay was unable to make a circuit and hence activate the board. So I have to get a new AP2 board from Arceuro when things free up again.I've been round the houses with this problem but at least the machine has go a complete facelift as regards electronic boards. The machine was bought new by myself maybe 10yrs ago now and it has served me well doing the bits and pieces that I come accross. Hopefully for many more years when I get this board replaced. Thanks for the pointers everyone.


  3. #23

    So, one experience I read (amongst many) was someone modifying the AP2 board to remove the transformer as they could feed a local 12V DC straight into the onboard regulator on the AP2 PCB. They removed the transformer and inserted 2 pieces solid-strand wire from the two primary terminals to the two secondary terminals, then removed the 110VAC (this was an American site) input to the board and sourced 12V from "elsewhere". That fed into the local bridge and onto the local 7805 regulator. That could be a very easy fix for you if you want to avoid the cost of a new AP2.

    Chances are its an embedded thermal fuse in the primary that's gone.

    Very useful information and follow-up. Thanks.

  4. #24
    If it's definitely 12v I think I will try and source a new transformer. RS is still online. Desolder and drop the new one in. Nothing beats a try! Could always fall back on the 12v direct supply as plan B.


  5. #25
    See the link in post #21 - it's part-way down that page that describes the removal of the PSU. You sound like you know what you're talking about so you be able to eyeball the rectifier / smoothing / regulation in establishing a suitable transformer replacement.

  6. #26


  7. #27
    Hi Folks
    Final update on the goose chase. It wasn't the BOB, it wasn't the main motor board, nor was it the AP2 board. It was a circular magnet that had fell off the bottom end of the motor spindle which must send some signals via sensors back to the motor board. Discovered when I went to investigate the last area possible, the motor and the leads from the motor board. The magnet shaped like a polo mint was lying inside the plastic cover when removed. Machine is well enough dismantled now all I have to do is reassemble. Secured the magnet back on to it's register on the main shaft with some Superglue. Motor back into life. What a chase. For anyone experiencing the same problem I would recommend lifting the motor out and checking it would save alot of time and head scratching. Thanks all for the feedback and encouragement. Soon get swarf flying out the door!

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