Mazak QT20

Hello
I need a bit of help, i have an old mazak qt20 with a T1 control,
I have an error coming up on the screen saying F error excess-x,
To reset the error i have to power off the machine and when i power up it clears but the error comes back when i try to home it in x axis. if i leave the machine off for until the next day when i power up it will find home and i can maybe run 4 or 5 cycles before it stops again with same error.
I have read on some posts about a counter balance on the x axis but don't know what i am looking at.
I know the machine is old (1984) but i find it very useful when it worked.

Any help would be greatly appreciated

Thanks
Enda

I have found that the only solution is to replace X axis drive,take note of all the small pin connectors on the board and make sure the new board is the same, you will probably have to move some of them.

I buy them second hand. X & Z are the same.

You could try putting heater in cabinet ( 60 watt bulb) it may help.

Check the spring coupling between the encoder and ball screw. It is held in place with a small set screw that may slip and cause an F excess error. The spring itself may be cracked and cause the same problem.

Thanks for your replies. I checked the coupling and its fine.
I have swapped the x drive card with the z and i still get the error, and i noticed over the last few days that when the machine is powered on and not used it will error as soon i move the x axis. I also noticed that sometimes when i have the machine in hand wheel mode and move the x axis the x value on the screen is moving but the axis is not.
Could it be a wiring issue, i was going to send the x axis drive card to get checked out but when i still had error using the other drive card i guessed the drive is ok.
Is there any mazak technicians in Ireland.

Try swapping encoders with Z axis. I've seen plenty of them go bad.

You could try Seamus Maquire in England 00447976360209, I find him very helpful.
Or Ivan McCullough 00447710802399 or David McHugh 00447798924472 of Machine tool Maintenance, Belfast

I tried swapping encoders but still the same error.

Thanks for the numbers Murphyc1, i will phone and see how i get on. I will let you know if they find anything.

Enda

Enda,
Are you still in trouble with this machine?
Possible the x axis break is staying on. this will show an overload on the drive.
it can take a drive some hours to reset, explaining why it runs after a period of downtime.

support for this machine is through H.W. Machine Tools Co. Ltd in Ireland and if you call 01-4502755 or 086 2569396 I will discuss.

regards
Ken

The master PCB is bad LX53

where do i find the master PCB LX53
Can this be repaired ?

Hello

Are you still in trouble with this machine?"" And Did You do well?? What was it??
do You remember?? I have T1 machine and the same errror ...???

Hi,

please give some pictures of the monitor and axis controller, when you get the alarm.

best regards
mazak-user

Hello
I will try to describe the problem.
I turn on cnc and try to go on "home" and there is no problem going up (+x) left right (-z,+z) but if you move down (-x) it just will not go and there is an error F error excess-x,
I tried to move it by hand and there is no problem, its going down (-x) smoothly, easy. So I don't think it is mechanical problem.
I did some pictures of the machine but sorry I do not know how the axis controller look like. Maybe you can point me.
PS I am a noob in cnc ..just starting...

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We have the same problem with QT 20 , we changed x axis drive with one from scrap machine and it worked OK for a while. We then got errors in both axis, we slowed down rapids in parameters and it is working fine. On another machine we were getting same problem and found that drive shaft for encoder in end of X axis ballscrew was loose, fixed that and it was OK.