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Hydraulics are great....til something simple fails.  Glad you found the problems.

I finished up my mill retrofit this week.  All was great and everything is perfect.  That is til one axis suddenly failed.  The brake would not release.  It was fine first day, boom then nothing.  Checked all wiring, power fine, jump switches to confirm.  Manufacture sent me overnight another servo motor.  I put it in and same problem.  WTH?  I rechecked power at plug.  Yup.  Tore my head apart......then I got to thinking.  I pull the factory plug off the harness to find they didn't snap the pin in tight and when I pushed the plug on it would slide the pin back and not make contact.  Ugh.  Always something simple.

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Seen that a lot when in the Navy. First thing to check on new and unproven parts what connect such as those do. Got to ensure the females receive the male pins correctly too sometimes. Seen them opened too far and don't crimp onto the male when it's inserted effectively. Bad deal to t/s and can really eat up the hours......

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I had checked the voltage at the plug using paper clips pushed into the holes(really tiny pins).   So for the life of me couldn't figure out why no power?   After the second motor failed I knew there had to be something awry and that is when I though about the plug itself.  The paperclip was getting down to the bottom and making contact but the socket was too deep for the pin on the motor.   Doh.  Lesson learned.

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Wait till you get into finding why you have voltage on a pin yet it will not carry any current. This is usually related to a defective termination or wiring land but it can be a SOB to find. I used to bring out the TDR, (time domain reflectometer) to send a signal down the line which was calibrated in travel time to inches or centimeters calculations. In radar you can have several hundred, to thousands of feet of lines to work with so this is a handy tool to have. 

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That was my thought....voltage but no current??  Didn't have my amp clamp handy to see if I could trace it somehow.  Lucky I found the bad plug.

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Yup. When you get a pushed pin in a connector or a compromised wire termination, the contact is so slight the voltage will readily show on a meter but the circuit won't pull any current. This is usually found when you ask the apparatus to operate and the monitoring meter immediately goes to zero, or close to it.

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6 hours ago, Rob said:

Wait till you get into finding why you have voltage on a pin yet it will not carry any current. This is usually related to a defective termination or wiring land but it can be a SOB to find. I used to bring out the TDR, (time domain reflectometer) to send a signal down the line which was calibrated in travel time to inches or centimeters calculations. In radar you can have several hundred, to thousands of feet of lines to work with so this is a handy tool to have. 

Sounds like something from Back to the Future.

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It's the kind of shit I got involved with during my working career. I got called in when maintaining technicians could go no further with, or locate a problem. Water intrusion into splices, terminations, connection points, etc. were problematic scenarios. New installs usually fall back onto contractors or installing entities but once the warranty period expires, the field engineers, (such as myself) get involved when something is out of service for a spell.

Could be both interesting, and maddening at the same time. 

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New valve cartridge arrived at the shop yesterday afternoon. I'll get it replaced shortly.  I noticed a high conductive resistance across the Cole-Hersee magnetic switch,  (solenoid) that powers the hydraulic motor so ordered a replacement. It may arrive today or tomorrow. This pumping unit is kind of hard to get to when installed so don't want to do the job twice.....

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Posted (edited)

I don't remember if I let you folks see this video or not but my ramp hydraulic pump is back together and working fine. The hydraulic cylinders showed up yesterday so once I figure what I'm doing with the trailer, I'll get them in use.

Here's another 3 minute or so waste of your time watching a video:

 

 

Edited by Rob

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Why a cylinder change?

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They both seep and the chrome rods are gouged in a couple of places. Cannot keep seals in them any longer. One rod is bent a little. I couldn't re rod them for the replacement cost.

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On 4/24/2018 at 8:15 AM, Rob said:

Here's another 3 minute or so waste of your time watching a video:

Something to do to pass the time at work..............LOL.

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1 hour ago, Freightrain said:

Something to do to pass the time at work..............LOL.

I thought that's what porn was for.  

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