AMC servo amplifiers are junk.

they may also just be using rejected junk pile parts instead of trying to obscure the original parts.

AMC is kind of pricey isn't it? If you just want some expensive stuff I have the Rand cards that came out of the Hurco on a shelf.
I think they all work, but who knows.
I am running the Hurco with GeckoDrive 320X step direction input servo drives. They work ok, but I do wish I had gone with the Viper 200s instead sometimes.

I have one of these amps on the shelf because nobody repairs them for less than you can buy a replacement from a different maker. And they are TOTAL ASSHOLES for grinding off the tops of the devices inside so you can't trouble shoot them. I showed mine to an electronics engineer friend and he has seen the grinding business before on other products. He told me that the grinding often shortens the life of the device because of the vibrations from the grinding. He has nothing but disdain for companies that act that way. So I totally agree with you, AMC can eat shit and die as far as I'm concerned. Eric

I don't condone companies grinding off component part numbers, but I work at a plant, some 60+ acres under roof, producing over a million tires per month, they have AMC drives on some production equipment that runs 24/7. In the years I have worked there, I have never replaced an AMC drive. I have replaced my failed Gentek drives with AMC drives, properly sized, no problems. Replacement Gentek drives, $800, AMC Drives $335, 10+ years later, no problems, outperform original drives.
Other possibilities is that the designers didn't know how to size or apply a drive properly. Any product with a design factor too low will have a high failure rate.
RogerN

Who sells 20A, 140V drives for less than $335?
RogerN

It was OEM equippment.
I've got three of those gecko servo drives that I still havent gotten around to integrating into an intended project but these AMC drives are in the Fadal Machining centers which uses analog +/- 10v servo input, and I'm certainly not interested in doing a complete retrofit on those.
I've gradually switched the other Fadal's to use the Glentek 4568 for XYZ, along with a smaller servo dynamics unit for the rotary table and so this is the last one that is still using AMC drives...I thought I had a spare in a box downstairs and I was definitely taken aback when it became apparent that inside the box were 1/2 dozen broken AMC drives.
So I robbed the AMC drive that WAS being used on one of the machines for rotary table and used it to fix the other machine, eventually I'll have to put an amp back into it but fortunately I have a brand new servo dynamic one in inventory so no problemo, mostly I just lost some time doing the repairs today is all.

Viper 200 - 170Volts, 20 Amps One each price is $239

I should add that's 20 amps continuous.

That would probably be great for replacing steppers with servos, such as a Mach 3 application. My own application is replacing the servo drives on my Anilam CNC Bridgeport mill. It uses +/-10VDC control signal, plus tachometer feedback, and the loop is closed by the Anilam linear scale feedback going to the controller. To use the Viper drive, I'd need to convert the controls +/-10V signal to step and direction signals and convert the tach voltage to encoder pulses/ or add a tach to the motor. The AMC drives I used are controlled by +/-10V signal, use tach feedback, and are a great replacement for the original Glentek drives.
One potential problem with the AMC drive, IIRC, their current rating is the peak current rating. If an OEM replaces a 20A continuous drive with an AMC 20A peak current drive, there could be a high failure rate unless the design only needs 10A (or less) continuous.
RogerN

One potential problem is that, IIRC, AMC rates their amplifiers for peak current, not continuous current. So if the OEM replaced, for instance, a 30A continuous drive, with an AMC 30A peak drive, it's probably going to have a high failure rate. If you order any new AMC drives, I would recommend ordering a higher current drive, approximately 2X what you use now.
I've never needed to call AMC for service or support so I don't know if they are helpful.
RogerN

I suspected they wouldn't really be a suitable direct replacement. The Vipers and the Geckos both close loop to themselves directly to an encoder. All they do is give an error output back to the controller.
That would be an issue.

If the servo motors had encoders on them it should be a suitable replacement. If the linear scales went to a LinuxCNC controller (and maybe Mach3), it could give step and direction until the table was in the programmed position. The drive would handle actual motor encoder steps and the controller would keep it stepping to get to the linear encoder position.
RogerN

"We're sorry for your bad experiences with ADVANCED Motion Controls. We remove the identifying marks on key components for the simple reason of self preservation. Our drives are designed and manufactured in the United States, not China, but we have seen many attempts at trying to copy us. Our survival depends on constant innovation as well as the preservation of established product lines. By removing identifying marks we don't make it impossible to copy us but we do make it more difficult. The manufacturing base in the United States has rapidly dwindled over the last 30 years but AMC has hung in there because we vigorously protect our Intellectual Property. As for quality we feel we are a world class leader when it comes to on-time delivery and reliability. This can be seen in the numerous military and medical applications that we are on. There have been many occasions where we were told that we are the most reliable piece on someone's machine. Yes we have seen our share of failures but if you think about it, even the most reliable companies in the world have had their problems. For example Apple had issues with cracked screens on their iphones, Toyota has had major recalls and Boeing has had issues with lithium batteries. We are proud to say we have learned from the past and our products are more reliable than ever and we expect our products to continue to improve into the future."
Chat Conversation End
Few things irritate me more than industrial electronics manufacturing companies that produce unreliable products, who don't publish their schematics and/or those who grind off or otherwise intentionally obscure component part identification numbers.
And so, to Advanced Motion Controls of Camarillo, Ca, my congratulations!
-you've certainly hit a tricecta as far as I'm in concerned, and I even have a box full of your god damned garbage to prove it.

Outside of the meaningless marketing speak garbage answer, did they offer any sort of solution or repair service/trade in/up for your faulted controllers?

I've been a communication contractor for over 20 years and I can't count the number of times my dissatisfaction level and interaction with a company has been elevated up to the highest level of incompetence because of failure after failure in service or performance or both only to be told, "We pride ourselves on our customer service." Why say that to somebody who obviously has a problem with your service. Its just a slap in the face instead of an address to their problems. In my case it often results in my looking for another vendor. I've had companies who I've spent hundreds of thousands of dollars with lose business my because of that sentence. Well, that sentence was the straw that broke the camel's back anyway.
Seriously. Clearly you aren't happy with their service or you would never have gotten that far. Morons.
If you really need to deal with them I think I might have replied, "Ok fine. Show me. I don't care how wonderful you are to somebody else. Show me how you are going to take care of me."

And that statement about them having seen many examples of people trying to copy their drives is suspect. If a Chinese company wanted to reverse engineer one of their drives they would have and would be selling them now. In fact, if anybody in the USA wanted to do the same they already would have. Grinding off the device markings only makes it hard to have the drives serviced when they break. So you either need to send it to AMC for service or buy another one from AMC or another maker. Which is what I did. Since there is no competition for repairing the AMC drives, but there is competition for buying new drives, I buy Glentek drives. They can be repaired by many outfits and even by a friend of mine who is an electrical engineer. What AMC does by removing the identification of the devices in their drives is just plain petty and greedy because it makes them the only company who can repair them. Eric

Nope.
Since I now have 4 of them in a box, (a couple of others were returned for 'core charge' quite some time ago) Im probably going to investigate further.
Specifically, the typical failure mode is that the red/ green ready indicator led simply does not come on, to me this indicates a failure in the logic power supply section...shouldn't be too difficult to at least try a couple of easy tests, specifically, I'm going to look for leakage at the electrolytic filter caps that reside just downstream from the DC input, of which there's three, and I have a sneaking hunch...

always check the power supply is a good first move. Hell, I had a bad bench power supply that was caused by a bad power supply inside the power supply. It sadly took longer to diagnose than it should have.

I noted when I opened up a Chinese auto darkening welding helmet filter that the device markings had been ground off and thought it odd but maybe the Chinese didn't want their compatriots copying their work.