Z axis faults and falls to table

[imaginemw]

My '89 Fadal 4020 decided to start acting up today by faulting out the axis' and then the head slowly falls to the table. I reset the e-stop fault, return to "home" and the problem eventually repeats itself. What may be causing the head to fall down to the table? I can understand the axis faulting out and sitting idle (which it's always done in the past) but now the head falls and e-stop does nothing to stop it! Thanks in advance for any advice.

[Dyad1]

imaginemw,
Will the head continue to go down if the main power switch is off?

[carbidecraters]

Typically this means a counterweight pin was left in after moving.

[imaginemw]

Yes, it has fallen with the power off.

[imaginemw]

......I found a relay loose, reset it, and so far the machine seems happier today. I'll keep you posted.

[carbidecraters]

Must be a TRM or EMC

[imaginemw]

Well the relay fix was too good to be true. The problem has reared it's ugly head once again. Any ideas?

[carbidecraters]

Which machine was it?

[imaginemw]

It's a '89 4020 Model 904-1. I've kept it powered up for last day or so and now today it's seems to be running fine. Do I possibly have caps going bad? Losing power after being powered down for a few days?

[gaswiz69]

Your gib straps are loose. Look in the maintenance manual for the procedure.

[imaginemw]

Will do. I'll keep you posted. Thanks.

[imaginemw]

Update....I adjusted the gibs (way loose!) and replaced a bad amp board. I'm and up and running again. Thanks for the help.