Denford Software & Machines

Last week i some how managed to crash the x axis on my triac and break the timing belt .
Today iv repaired this and switched the machine on only to find the spindle comes on when i power up and it wont switch off .
Does anyone have any ideas as to where the fault could lay and if me crashing it could be related??
The machine homes in ok while the spindle is running but the spindle wont respond to M5 or the emergency stop button or even the reset button to that matter so im scratching my head as to what it can be.

is the spindle running fast or around 200rpm.

I would take a look at the spindle drive & maybee the motor.
What model of Triac is it?
If it, a Triac PC or Triac VMC then you should have a Sprint 1200 drive & a SEM spindle motor. If you remove wires 54 & 55 from terminals 4 & 5 (run contact) on the Sprint drive. If the spindle still runs on power it may be worth disconecting the motor armature & Tacho from the drive & use a meter to check if the drive is still outputting a DC voltage. It may be worth checking the Tacho for shorts or grounding.

Thanks for the relies so far guys.
I thinks its a 1986 model with fanuc omc system and has a lynx o8 drive card.
Its got to be something silly and simple because i had it powered up the other day and didnt have this problem so im thinking along the lines of a relay or something sticking but i could be wrong

I'd agree it's something silly like a wire come loose or broken.
Check the tacho wires and command input wires to the drive.
Although, it's strange how the drive would be enable as soon as you power up - the logic should only enable the spindle when it knows all is ok (and probably then only when M03 or M04 is programmed).

Could the thyristor cause this problem at all by any chance?

Problem found, the thyristor has gone again .
This is the second time so iv just ordered a sprint 3200i in 16 amp so i hope this works better