Denford Software & Machines

Hi guys. I hope you help. I have sold my dad's Orac which on the day of sale decided it wasn't going to work any more!
The spindle, x and z axis no longer move in any mode. The emergency stop button no longer puts the machine in manual mode (instead the axis L.S OVERIDE does)
The guy who has paid for it and transported it obviously wants it working or his money back so in hoping you can help.

I have repaired the power board by the drivers as there were faulty components (electrolytic and paper caps) The inputs to the motor are all reading 158v.
I've looked through all the schematics but I'm at a bit of a loss now.

Photos attached

Power board repaired

Are you holding in the axis limit override switch?

You need to manually drive it off the switch while holding in the button.

Hi, I have no movement at all. There is a reset button on the bottom right at the front. Next to that more in the middle is the axis L.S OVERIDE button. So should I be pressing this button whilst trying to move the axis? Any idea why the emergency stop doesn't put the machine into manual mode?

Sorry I'm probably being really dense but this was my dads machine not mine. I'm more into the electronics than the mechanics side of things. Do you think that it is on a limit switch which is stopping everything from working?

Hi Andy, make sure the EM stop is reset otherwise nothing will work, check you are in Manual mode and hold in the override switch on the underside, holding the switch in use the axis buttons to move the carriage off the limit switch/es.
To move off the limits move the Z towards tailstock, move X axis towards the operator.

You can see the Z axis limit switch on the top surface of the back shear of the bed, using an allen key loosen the M6 screw that holds the switch in place and slide away from the cross slide/carriage.
The X limit can be seen by removing the 2 screws holding the top back cross slide cover in place, you will be able to check if the switch is activated with the cover removed.

Have you changed the split 0.01uf capacitors ?

Marcus

Hi, thanks Marcus. I will need to check this all out when I get up to manchester again. Won't be for a couple of weeeks. I have replaced several caps not just the cracked ones.
The Z axis switch does not appear to be anywhere near being activated. I was looking for the X axis switch vbut couldnt find it. Do you happen to have any pictures?

Regards

Andy

As I have said the emergency stop does not do anything any more. It used to put the machine into Manual Mode but now the axis reset switch does this. I cannot move the x and z axis at all and I was wondering if it had anything to do with the emergency stop not working any more? could it be a relay stuck? If so which one?

Andy, re the X limit switch, read the last para in my last reply (remove the 2 screws holding the cross slide top cover to view
the X limit)

When you turn the machine power switch on you should hear a contactor close, control circuits are switched ON/OFF by the relay so if not closing you will have no controls working.

There is also an electronic overload built into the motor control board, this if tripped I believe also prevents axis movement.

Marcus

Thank you so much Marcus. You've been such a great help to a complete novice! I will check all of these things and get back to you. I hope it's something simple!
Which board is the motor control board?

When viewing the lathe from the back the motor control board is positioned on the extreme right side of the plate.

Marcus

Does anyone happen to know the location of the trip on the motor control board?

It's an electronic trip and should reset when the Em stop is activated.

Something I had previously was metal chips got into the machine light switch and shorted connections,
this prevented the axis operating in any way. Martin advised the cure for my problem.
Just pull the cover off and check all connections are clear of swarf/chips.

Marcus

That's the problem. Nothing happens when the RM1 switch is pressed. It used to go into manual mode but now it does not reset anything. The machine doesn't do anything when the switch is pressed. I'm checking the limit switch in 30 mins so hopefully I'll have it sorted!