Y encoder motor error on Sabre 408

[Jeff28]

Hey everyone, our Sabre 408 router went and died on us today. When we try and turn it on it beeps, then does a long tone and an error message comes up on the keyboard saying Y Encoder Motor error. There is also a light in the electrical box that says AMP FAULT that is on.

Little back story on our situation, we recently replaced the entire motor with a spare after the cables underneath were ripped out during use. The router seemed to work fine after this. A few days ago we had a power outage while the router was running, it worked fine after this too. After running about 5 more sheets the router stopped working. We were just jogging the carriage back to the front of the machine (not running a file), it started moving way faster than normal for about a half second then it stopped working.

So far ive come up with a few things this could be based on the user manual and asking around: a limit switch, an connection issue, or a computer component. I dont think its a limit switch based on how it failed. Just by visual inspection all the connections in qustion look good but there could be issues internally. With the power outage and seeming power surge wghile jogging the carriage i suspect a computer component has fried.

What ive done so far to fix my problem is take spare cables for the Y encoder and motor from another router and replaced the ones on our current router, Ive physically moved the carriage away from the y limit switches and tried to restart the machine.

 

[Ian Stewart-Koster]

Can you borrow a servo with encoder, from another machine - just plug it in, not connected to the drive belts - and see if the initialising etc seems to work

 

[Jeff28]

Can you borrow a servo with encoder, from another machine - just plug it in, not connected to the drive belts - and see if the initialising etc seems to work

we do have a spare router to get parts from but im not sure what part youre talking about

 

[fdarling]

Hey everyone, our Sabre 408 router went and died on us today. When we try and turn it on it beeps, then does a long tone and an error message comes up on the keyboard saying Y Encoder Motor error. There is also a light in the electrical box that says AMP FAULT that is on.

Little back story on our situation, we recently replaced the entire motor with a spare after the cables underneath were ripped out during use. The router seemed to work fine after this. A few days ago we had a power outage while the router was running, it worked fine after this too. After running about 5 more sheets the router stopped working. We were just jogging the carriage back to the front of the machine (not running a file), it started moving way faster than normal for about a half second then it stopped working.

So far ive come up with a few things this could be based on the user manual and asking around: a limit switch, an connection issue, or a computer component. I dont think its a limit switch based on how it failed. Just by visual inspection all the connections in qustion look good but there could be issues internally. With the power outage and seeming power surge wghile jogging the carriage i suspect a computer component has fried.

What ive done so far to fix my problem is take spare cables for the Y encoder and motor from another router and replaced the ones on our current router, Ive physically moved the carriage away from the y limit switches and tried to restart the machine.

I recently helped someone diagnose a similar issue, it was ultimately a faulty limit switch connector that was making the system thing it was on the Y+ limit. The significant of this is that the limit switches not only go to the "brains", but go to the servo amplifier ribbon cable so that they inhibit motion in the direction of the limit switch. This will effectively raise an "amplifier fault" because it really means "amplifier inhibited" which is due to one of three reasons:

1) The amplifier is disabled (via its inhibit pin on the ribbon cable)
2) The amplifier is disabled *in a direction* via its clockwise and counter-clockwise inhibit pins (meant to hook to limit switches)
3) The amplifier is enabled, but experiencing a short-circuit on the motor (or other internal issue), and is "inhibited" as a measure to protect itself

When the Gerber system starts up, it by default has the servo amplifiers disabled. It's only when it tries to enable them, but doesn't see the "inhibited" signal go away, that it gives this error. You must determine why it's being inhibited. This is most reliably done by using a USB logic analyzer and some grabber probes, and grabbing the legs of various ICs involved in propagating the limit switch / inhibit / inhibited signals.

Here is such a logic analyzer:

$12.69 -- HiLetgo USB Logic Analyzer Device With EMI Ferrite Ring USB Cable 24MHz 8CH 24MHz 8 Channel UART IIC SPI Debug
https://www.amazon.com/HiLetgo-Analyzer-Ferrite-Channel-Arduino/dp/B077LSG5P2/

And the grabbers:

$20.99 -- Goupchn 10PCS SMD IC Test Hook Clips with Silicone Jumper Wires Test Leads Kit for Logic Analyzer 5 Colors
https://www.amazon.com/10PCS-Grabber-Jumper-Analyzer-Colors/dp/B083PRVPCR/

And finally the USB logic analyzer software:

Logic 1.x Download | Saleae Support

Logic 1.x Download | Saleae Support

support.saleae.com

Also, you'll want to verify that the Y encoder is being "seen" by the brains, which you can do by checking some pins on J125 header that hooks via a ribbon cable to the CPU board. If it cannot see the encoder signal, than it will conclude that the motor isn't moving when it's told to (even though it is), and get angry about it. However, in this case of you having an amplifier fault, that means you don't need to look at the encoder quite yet.

I offer phone support to help you use the logic analyzer to hunt down the problem. Once you figure out which signals aren't looking like you'd expect, then we can figure out what the root cause is (faulty amplifier, faulty wiring, burned out IC, etc.) If anyone needs this kind of support, please direct message me.