KX3 Spindle Problem

[Doddy]

Ugh. I wish I'd never asked, now. I'm throwing an awful, awful lot of guesswork into this that might be completely misleading.

Have you seen this link and does it look sensible and appropriate?

https://littlemachineshop.com/images...UpgradeKit.pdf

If only for the association with the board. I'm reading more, and this is hitting the territory I'm in with spindle speed control on a SX2.7. But, my interest lies if this is OEM or a modification to the KX3

EDIT: Though read somewhere that Sieg used these boards themselves for the CNC machines.

I'm out of ideas here - there's clearly two opto-couplers that are connected to the spindle-control board - these could be step/dir but that's guesswork. I would expect that these would be involved with the speed control given the nature of this board - if you had access to a scope it would fall into the "interesting" category of investigation, but you're looking at a fairly proprietary interface now between this and the BLDC controller in the Seig.

But you've convinced yourself that your analogue wiring to the board is correct?

EDIT 2: I'd check through that link and verify your wiring as a first port of call.

My experience of the BLDC board is that can be fragile (mine popped two IGBT and a fair bit of collateral circuitry early in its life - replaced under warranty), and you've suggested that you may have had similar problems and replaced the board yourself in the past. So there's a question that you have no spindle control (no rotation)... is it the BoB - you suggest not / this is replaced. Is it this board or the spindle board (BLDC controller) - and that can be a challenge to understand (sorry, that's not very helpful I know)